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TRANSPORT and ROAD RESEARCH LABORATORY
Department of the Environment Department of Transport
SUPPLEMENTARY REPORT 682
THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M 180 (SANDTOFT TO TRENT SECTION)
by
J M Gregory FIHE
Any views expressed in this Report are not necessarily those of the Department of the Environment or of the Department of Transport
Construction and Maintenance Division Highways Department
Transport and Road Research Laboratory Crowthorne, Berkshire
1981 ISSN 0305-1315
Ownership of the Transport Research Laboratory was transferred from the Department of Transport to a subsidiary of the Transport Research Foundation on 1 st April 1996.
This report has been reproduced by permission of the Controller of HMSO. Extracts from the text may be reproduced, except for commercial purposes, provided the source is acknowledged.
Abstract
1.
2.
.
CONTENTS
Introduction
Construction
2.1 Earthworks
2.2 Sub-base
2.3 Separation membrane
2.4 Carriageway paving
2.4.1 Concrete
2.4.1.1 Mixing and transport
2.4.1.2 Control
2.4.2 Reinforcement
2.4.2.1 Laps
2.4.3 Joints
2.4.3.1 Expansion joints
2.4.3.2 Contraction joints
2.4.3.3 Wide-flange beam joints
2.4.3.4 Construction joints in CRCP
2.4.3.5 Longitudinal joints
2.4.3.6 Joints between concrete and flexible construction
2.4.4 Surface texture
2.5 Hardshoulder
2.5.1 Transverse joints
Testing and control
3.1 Sub-base
3.1.1 Granular sub-base material Type 1
3.1.2 Cement-bound granular material
Page
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5.
.
7.
8.
9.
3.2 Concrete carriageway slabs
3.2.1 Plastic concrete
3.2.2 Hardened concrete
3.2.2.1 Cores
3.2.3 Surface characteristics
3.2.3.1 Surface regularity
3.2.3.2 Surface texture
3.3 Concrete slabs in hardshoulders
3.3.1 Plastic concrete
3.3.2 Hardened concrete
3.3.3 Surface characteristics
3.3.3.1 Surface regularity
3.3.3.2 Surface texture
Remedial actions
Comments on construction
5.1 Tolerances
5.1.1
5.1.2
5.1.3
5.1.4
Slab thickness
Reinforcement position
Reinforcement ripple
Omission of separation membrane
Costs
Performance
Acknowledgements
References
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(C} CROWN COPYRIGHT 1981 Extracts from the text may be reproduced, except for
commercial purposes, provided the source is acknowledged
THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION)
ABSTRACT
This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of this experiment has been reported in SR 653.
Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output of 502m was achieved. The hardshoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.
The results of tests on the plastic and the hardened concrete are reported, together with summaries of the results of tests on the finished surfaces.
1. INTRODUCTION
The major purpose of the experiment is the investigation of the design, construction, cost and performance of
continuously reinforced concrete pavements (CRCP). Variables for other purposes are also included in the experi-
mental carriageways; the design of the experiment has been described in Supplementary Report 6531. The layout
of the experiment is shown in Figure 1.
2. CONSTRUCTION
The contractor for all the works connected with the contract was Sir Alfred McAlpine and Son (Northern) Limited;
work on the 24 month contract commenced in November 1976. The contract length was extended by four months;
the majority of the extension granted was as a result of exceptionally adverse weather conditions early in the
contract period.
2.1 Earthworks
Nearly all the earthworks consisted of shallow embankments; these were constructed of imported marl fill
from nearby disused brickworks.
Settlements of up to one metre are predicted to occur at the eastern end of the section (east o f chainage
10157+00), where there is underlying peat up to 6m thick. The CRCP over this area have been strengthened by
additional transverse reinforcement (16 mm diameter bars of deformed steel, placed at 500 m m centres). Settle-
ments are being frequently monitored and the performance of the CRCP over this length will be watched with
particular interest.
2.2 Sub-base
The sub-base under all sections of jointed pavement, including transition bays, was 180 mm thick granular
material Type 1 ; it complied with the requirements of the Department of the Environment Specification for road
and bridge works 2. The crushed limestone aggregate used was spread by graders and compacted by vibratory
rollers.
Under the CRCP sections the sub-base consisted of 150 mm of cement-bound granular material laid on a
similar Type 1 granular sub-base material of such thickness that the total construction depth was 460 mm. The
cement-bound granular material was mostly made with a 37.5 mm maximum size slag aggregate with cement
contents varying from 4 to 7 per cent. It was mixed in the 7.5 m 3 capacity tilting drum mixer used to produce the
pavement quality concrete.and laid, by a rubber-tyred bituminous-materials paver, in widths up to 5.3m; compaction
was by a combination of vibratory and smooth-wheeled rollers. Small areas were infdled with cement-bound
granular material using the crushed limestone granular Type 1 material as aggregate. After rolling, the sub-base
was cured with a bituminous emulsion spray.
2.3 Separation membrane
A separation membrane, used beneath all the sections except the CRCP and the transition sections and half
the length of unreinforced pavement with narrow unsealed joint grooves, consisted of a 65 pan thick polythene
sheering laid on the sub-base.
2.4 Carriageway paving
The construction o f each 11.2m concrete carriageway was carried out in one operation using the Guntert
and Zimmerman slip-form paver shown in Hate 1. Control wires, positioned on either side of the paver outside its
crawler tracks were used for level control; one of these wires was also used for control of alignment. The guide
wires were supported on steel pins spaced 6m apar t . Following the paver were a transverse joint groove-forming
machine, a transverse joint finisher, and a combined brush-texturing and curing spray machine all mounted on
rubber-tyred wheels and guided f rom the control wires. Box-outs for road studs were inserted by hand after the
transverse joint finisher had passed and were removed after the curing spray was applied.
On both carriageways paving commenced at the western end of the site. On the Westbound carriageway,
a 6m long transition slab at the western end o f the 210 m m thick CRCP section with fabric reinforcement was
omit ted in order to permit access for lorries transporting the concrete from the mixing plant; this slab was
subsequently hand laid. Paving started on 21 June 1978 with the laying of the trial lengths (in unreinforced
construction) on the Westbound carriageway. This carriageway was completed on 13 July 1978. On the Eastbound
carriageway, paving commenced on 17 July 1978 and was completed on 5 August 1978. The maximum length
laid in one day was 1132m and the average daily output was 502m.
2.4.1 Concrete: Three different concrete mixes were used during the construction of the carriageways; details
are given in Table 1.
TABLE 1
Concrete mix proportions
Material
Cement
Sand
Coarse Aggregate
Water
Air-entraining agent
Type
Ordinary Portland
Quartzitic (Zone 3)
Limestone 1 0 - 5 mm
Limestone 2 0 - 1 0 mm
Weight (kg) per m 3
Mix l Mix2
280 280
704 710
370 379
776 794
154 154
Mix 3
315
760
363
688
173
Varied between 80 and 120 cc per 50 kg of cement
Mix 1 was used for the period 21 June to 2 July 1978. Mix 2 was used for the period 3 July to 15 September 1978. Mix 3 was a pumped mix.
The pumped mix was used only at two locations on each carriageway where, because of the central bridge
piers, it was not possible to take the side-feeder through the bridges while attached to the slip-form paver.
Accelerated wear testing, as required by Clause 1001 of the Specification 2, showed that the limestone
aggregate proposed by the contractor was acceptable. The cement content used was the minimum allowed in the
Specification (280 kg/m3), a trend that has been observed on most concrete paving contracts where the indirect
tensile strength test has been used as the acceptance criterion.
2.4.1.1 Mixing and transport: Concrete mixing was carried out at a central batching and mixing plant set up
near the western end of the contract; the mixer was of the tilting-drum type with a capacity of 7.5m 3. The mixed
concrete was transported in 4-axle non-tipping ejector trucks with a 7.5m 3 capacity to match the batch size;
most loads were 7m 3. The trucks were fitted with hydraulically operated bulkheads and tailgates which enabled
rapid controlled discharge into the side-feeder attached to the slip-form paver. The concrete was only covered
during transit from the mixer to the paving site when weather conditions warranted this.
2.4.1.2 Control: Workability was controlled by means of the Slump Test carried out by the contractor at the
mixing plant and by the client at the laying site; the contractor also used a wat tmeter on the mixer as a control aid.
Similarly, air content measurements were made at both mixing and laying sites. For compliance with the indirect
tensile strength requirements, cylinders 150 mm in diameter by 150 mm and 300 m m long were made and tested
at 7 and 28 days. The results of all the control tests are summarised and discussed in Section 3.
2.4.2 Reinforcement: In the CRCP sections with bar mat reinforcement the longitudinal steel consisted of hot-
rolled deformed ribbed bars (Type 2); the transverse steel was of indented steel except in the 230 mm thick section
with mid-depth reinforcement where Type 2 ribbed bars were used. The longitudinal and transverse reinforcement
in the 210 mm thick section with the fabric reinforcement consisted of indented wire.
3
The reinforcement mats were placed with the longitudinal steel on top, except on the Eastbound carriageway
between chainages 10157+00 and 10165+65. There the mats were inverted with the transverse wires on top,
including the additional bars, to maintain adequate depth of longitudinal joint groove. On the Westbound carriageway,
over this length, the mats were not inverted but the same additional transverse steel was placed on top of the
longitudinal steel.
The methods of fabrication and of positioning the steel reinforcement were deliberately made the
responsibility of the contractor so that he was free to suggest any suitable method by which the reinforcement
would be positioned at the specified level.
All the bar mats and mesh fabric reinforcement for the CRCP sections were prefabricated in 12m lengths,
approximately 2.2m wide; the standard mesh fabric for the conventional jointed reinforcement sections was in
mats 6.4m long by 1.8m wide. The contractor elected to use free-standing reinforcement. The original proposal
was to weld bent steel o f the appropriate height to the mats in the factory. Difficulties were experienced at a very
early stage in this process, both in obtaining the necessary height tolerances and in packaging for transport to the
site. A system using 'ring spacers' shown in Plate 2, was evolved and, after trials for stability and accuracy of position,
this method was adopted for both the CRCP and the conventional reinforced sections. The ring spacers consisted
of two steel wires with spacer bars o f the appropriate height welded to them at fight angles. The spacers were
delivered flat on site in 6m lengths and then bent into roughly circular or elliptical shapes prior to positioning
the reinforcement mats by crane (Plate 2). The reinforcement was secured to the spacers by wire ties and the
completed steelwork was very stable.
2.4.2.1 Laps: No laps were required in the transverse direction for either the continuous or the conventional
reinforcement. However, in the longitudinal direction an adequate length of lap is vital to obtain good performance.
For the conventional jointed reinforced pavement the minimum lap length was 450 nun with the first transverse
wire o f one mat lying within the last complete mesh of the previous mat. For the CRCP sections the laps in the
longitudinal steel were specified to be at least 35 times the bar diameter and to be so arranged that not more than
one-third occurred in any transverse section. The use of skewed laps was permitted but the contractor opted to use
right-angled laps; a typical layout o f the steel in a CRCP section is shown in Figure 2.
2.4.3 Joints: The following five types of joint were constructed in the carriageways:-
i) expansion
ii) contraction a) with normal width grooves
b) with narrow grooves
iii) wide flange beam
iv) construction (in CRCP)
v) longitudinal
2.4.3.1 Expansion joints: These joints only occurred between transition slabs and at the ends of CRCP where
anchorages were used. The expansion joints contained 32 m m diameter mild steel dowel bars, 750 mm long at
300 m m centres; the dowels were supported by prefabricated mesh cradles on either side of a 25 mm thick •ler
board o f Parana pine capped after concreting with a sandwich board of stiff hardboard enclosing expanded
4
polystyrene. One half of each dowel bar was debonded using a polyvinyl sheath with 25 mm expansion space at
the end. The joint assembly was fixed to the sub-base with long nails, to prevent movement during the passage of
the slip-form paver. After the concrete had hardened, the capping above the filler board was removed leaving a
30 mm wide sealing groove that was subsequently fiUed with caulking and a cold-poured seahng compound, a
two-part polysulphide-based material.
2.4.3.2 Contraction joints: All joints of this type contained 25 mm diameter mild steel dowel bars, 400 mm long,
spaced at 300 mm centres. They were debonded over half their length with polyvinyl sheaths and were supported
on prefabricated assemblies fixed to the sub-base with long nails. As construction took place during the summer
period, bottom crack-inducers were omitted and the surface grooves were formed either by the insertion of a two-
part plastic former into a wet-formed groove or by sawing; in all cases the depth of the groove was 75 ram,
ie 0.27 of the nominal slab depth.
Where the grooves were wet formed, the top part of the former was removed after the concrete had hardened
and the 10 mm wide groove was sealed with the cold-poured sealing compound. In one section of the unreinforced
construction the joint grooves were of the narrow unsealed type, formed by sawing 3 mm wide grooves at between
8 and 18 hours after compaction of the concrete. The sealing grooves for contraction joints in the conventional
reinforced sections were widened to 35 mm by sawing and were sealed with the cold-poured compound used for
the other transverse joints.
2.4.3.3 Wide-flange beam joints: These joints have not been constructed previously in this country although they
have been widely used in the USA; details of the joint are shown in Figure 3. The steel beam was fabricated to a
length 120 mm less than the width of the carriageway, to allow for manoeuvring of the slip-form paver, and was
galvanised to give added corrosion protection. Great care was necessary in setting the beam into the concrete
sleeper beam so that its top surface was at the correct finished road level; no particular difficulties were experienced
in paving up to and over this type of joint which was occasionally used as an end of day joint. The grooves at
these joints were later sealed with cold-poured sealing compound.
2.4.3.4 Construction joints in CRCP: These joints were necessary at the end of a day's work or when there had
been a breakdown in the paving process; they have been the cause of problems in CRCP construction previously.
Because the joint faces are smooth there is no aggregate interlock, such as exists at a crack, and load transfer at
the joints is thus less effective; strengthening and special care in construction are required at these positions.
Strengthening was achieved by the inclusion of extra longitudinal bars, 1.5m long, of the same size and type
as in the adjoining slab; this increased the percentage of steel at the joint to a minimum of 1.0 per cent. The
additional bars were placed centrally across the joint at the same level as the main longitudinal steel. Extra
compaction of the concrete in the congested area at the construction joints was needed. The longitudinal bars of
the CRCP were continued through these joints, for which a split timber stop-end was used. Construction joints
were not sealed.
2.4.3.5 Longitudinal joints: The two longitudinal joint grooves were wet-formed, dividing the carriageway into
three equal widths. Bottom crack inducers were not used and each joint groove was formed by the insertion o f
5 mm wide polyethylene strip, either 57 or 75 mm deep depending on the slab depth, using inserters mounted on
the rear o f the slip-form paver. In both the unreinforced and reinforced jointed sections tie bars of 10 mm diameter
deformed steel, 750 m m long at 600 mm centres, were cranked and connected by spacer bars into assemblies that
were secured to the sub-base in a similar manner to the transverse joint assemblies. No tie bars were used in the
CRCP sections as the transverse steel had been designed for this purpose; there was at least 500 mm of continuous
transverse steel on either side o f the longitudinal joint.
The longitudinal joint between the carriageway and hardshoulder was tied by three 16 mm diameter mild
steel bars, l m long at 900 mm centres, inserted by hand (in cranked shape) into the edge of the slab at the centre of
each hardshoulder bay.
2.4.3.6 Joints between concrete and flexible construction: Flexible construction was only used at the two
extremities o f the contract, over the two underbridges and for the slip roads at the interchange. A stepped
transitional slab (rolling block) was used except at the slip road/main carriageway joint; a section through this
slab is shown in Figure 4.
2.4.4 Surface texture: A brushed surface texture was achieved with a mechanically operated brush 3m wide.
The site is in an open rural area, and potential noise nuisance is therefore minimal. I f plastic grooving had, in fact,
been specified there is as yet no machine available for producing this texture when the slab is slip-formed.
2.5 Hardshoulder
Over the greater part o f the contract there is a trapezoidal-shaped drainage channel which the contractor
elected to form integrally with the hardshoulder. A small Guntert and Zimmerman slip-form paver was used for
this construction; texturing and application o f curing spray were done manually. The contraction joint grooves
were all sawn. Where transverse joints occurred in the conventional carriageway, they were matched for type and
position in the hardshoulder.
The concrete mix and the methods of mixing and transporting were the same as for the carriageway paving.
The slip-form paver operated f rom a single guide wire with one track of the paver running on the already completed
carriageway slab, protected f rom abrasion damage by the use of mats; the other track ran on the sub-base as
Shown on Hate 3. Prior to paving the hardshoulders, the cranked tie bars were straightened and any loose bars
were grouted with an epoxy resin grout. Polythene membrane was used under the hardshoulders except alongside
the lengths of carriageway from which the underlay was omitted.
The longitudinal joint between the carriageways and hardshoulders was sealed using a 25 mm deep by 5 mm
wide polyethylene strip secured to the top o f the carriageway edge with an adhesive. Transverse texture was
applied manually to the hardshoulders by wire-brushing.
Paving o f the hardshoulders commenced on 11 August 1978 and was completed by 15 September 1978;
the max imum length laid in one day was 1266m and the average daily output was 657m.
2.5.1 Transverse joints: As the hardshoulders were ofunreinforced concrete using a limestone aggregate, the
transverse joints were spaced at 6m intervals. Where there were joints in the carriageways the joints in the hard-
shoulders coincided both in position and type except at the wide-flange beam joints where expansion joints were
used in the hardshoulders. Alongside the CRCP sections all the transverse joints were of the contraction type.
The dowel bars in all the transverse joints were positioned in prefabricated assemblies secured to the sub-base and
the joint grooves were formed by sawing.
The transverse joints, except the wide contraction joints and all expansion joints where cold-poured sealants
were used, were sealed with hot-poured sealants.
3. TESTING AND CONTROL
Despite the experimental nature of the contract no special measures were adopted for control and testing, the
contract would thus be carried out under conditions similar to those experienced on normal construction sites.
There was extensive liaison between the site staff and TRRL but all the compliance testing and measuring was
undertaken by site staff. Copies of the paving records and the testing data have been made available to TRRL,
together with other relevant information. This will enable the future performance of the pavements to be closely
correlated to construction, material, and environmental factors. A summary has been made of the relevant
information and is presented below.
3.1 Sub-base
3.1.1 Granular sub-base material Type 1: This was a crushed limestone (dolomite) from South Yorkshire;
75 samples were tested by the client and the contractor also carried out many tests on the material. Most
samples complied with the specification although there were occasional problems with excess fines.
3.1.2 Cement-bound granular material: The aggregate used for this material was a screened slag from a near-by
steel works; 15 grading tests were made and, although the material generally complied with the specification, five
tests showed slight deficiencies in the percentage passing a 37.5 mm sieve. Again the contractor also carried out
many tests with satisfactory results.
Initially, a cement content of 7 per cent was used but, because of the high strength obtained, this was
progressively reduced to 4 per cent. The results of tests on cubes and cores are summarised in Table 2.
TABLE 2
Summary of test results on cement-bound granular material
Cement Cubes Cores
[ i Dry density content Compressive strength Dry density No. of cores (per cent) No. of cubes at 7 days (N/mm 2) (kg/m 3) (kg/m 3)
Note:
7 6 5.5 5 4.5 4
11 23 23 40 48 57
11.64 10.12 10.29
6.56 6.93 6.02
2221 2176 2233 2100 2145 2128
14 27 25 60 57 69
2200 2180 2182 2117 2191 2156
A cement content of 4 per cent was used for most of the sub-base.
The thicknesses of the two sub-base materials (cement-bound granular and Type 1 granular) were measured
in the core holes and are summarised in Table 3.
TABLE 3
Thicknesses of sub-base materials beneath CRCP sections
Carriageway
Westbound
Eastbound
Section
210 nun fabric
230 mm mid-depth
250 mm third-depth
250 mm mid-depth
210 mm third-depth
210 mm mid-depth
230 mm third-depth
No. of cores
35
41
47
31
31
23
28
Sub-base material thicknesses (mm)
Cement-bound granular material
152 (150)
147 (150)
154 (150)
137 (150)
Type 1 granular material
106 (100)
88 (80)
68 (60)
88 (60)
106 (100)
105 (100)
91 (80)
150 (150)
145 (150)
146 (150)
Overall
258 (250)
235 (230)
223 (210)
225 (210)
256 (250)
250 (250)
237 (230)
The figures in parentheses are the specified thicknesses.
3.2 Concrete carriageway slabs
Extensive testing was carried out both on the plastic concrete and on the hardened concrete. Measurements
were also made of the surface regularity and texture.
3.2.1 Plastic concrete: Tests were undertaken both by the contractor for quality control and by the client for
determining compliance with the specification. The results relating to particular experimental sections and
averages for the whole contract are given in Tables 4 and 5. The sections are listed in the order of paving. The
slump-test results are given in Table 4 and the air contents of the concrete in Table 5.
The values of slump shown in Table 4 indicate that a slightly less workable mix was used in the Eastbound
carriageway (with a much reduced variability) than in the Westbound carriageway. From Table 5 it can be seen
that the air content o f the concrete used in the Eastbound carriageway was significantly greater than in that used
for the Westbound carriageway (again with a reduced variability).
3.2.2 Hardened concrete: The indirect tensile test was used to measure the concrete strength and the
acceptance criterion was that the average of any four consecutive results should have a value of not less than
2.3 N/mm 2. Cylinders 300 mm long and 150 mm diameter were made and tested at 7 and 28 days during the
construction of the carriageways and hardshoulders; during the paving of the first (Westbound) carriageway,
150 mm long cylinders with a diameter of 150 mm were also made and tested at 28 days. Density measurements
were made on all the cylinders at the time of testing and the results of these measurements are summarised in
Table 6; the indirect tensile test results are summarised in Table 7.
TABLE 4
Summary of slump test results
Section
WESTBOUND CARRIAGEWAY 280 mm Unreinforced 210 mm CRCPofabric reinforcement 280 mm Reinforced 230 mm CRCP-mid-depth 250 mm CRCP-third-depth 250 mm CRCP-mid-depth Complete carriageway including transitions
EASTBOUND CARRIAGEWAY 280 mm Unreinforced with narrow
joints 280 mm Unreinforced 280 mm Reinforced 210 mm CRCP-third-depth 210 mm CRCP-mid-depth 230 mm CRCP-third-depth Complete carriageway including transitions
BOTH CARRIAGEWAYS
Length (m)
No.
678 30 1572 29 504 15
1695 30 1689 35 1746 31
8279 186
678 14
1632 29 504 8
1698 24 1692 19 1746 17
8279 118
16558 304
Client's tests
Average S.D.* (mm) (mm)
34.0 20.1 17.5 10.8 21.3 9.2 22.7 12.2 44.0 45.0 35.3 25.5
29.0 26.4
26.8 12.2
26.2 11.6 21.9 8.0 19.6 10.1 30.5 14.3 23.8 11.0
24.7 I 1.8
27.3 22.0
* Standard deviation TABLE 5
Summary of air content test results
No.
15 22
7 21 24 21
120
10
23 7
22 22 24
114
234
Contractor's tests
Average S.D.* (mm) (mm)
38.5 15.2 26.8 20.5 21.4 5.6 21.0 8.8 21.5 12.5 25.7 8.6
24.9 14.1
18.0 6.8
18.9 6.6 20.0 5.8 22.3 9.8 25.0 9.1 20.4 8.1
21.2 8.3
23.1 t l . 8
Section
WESTBOUND CARRIAGEWAY 280 mm Unreinforced 210 mm CRCP-fabric reinforcement 280 mm Reinforced 230 mm CRCP-mid-depth 250 mm CRCP-third-depth 250 mm CRCP-mid-depth Complete carriageway including transitions
EASTBOUND CARRIAGEWAY 280 mm Unreinforced with narrow
joints 280 mm Unreinforced 280 mm Reinforced 210 mm CRCP-third-depth 210 mm CRCP-mid-depth 230 mm CRCP-third-depth Complete carriageway including transitions
BOTH CARRIAGEWAYS
Length (m) No.
Client's tests
Average S.D.* (%) (%) No.
678 25 3.5 2.0 15 1572 22 4.0 0.7 21
504 10 4.0 0.8 8 1695 23 3.6 1.5 21 1689 24 4.6 0.8 24 1746 23 4.4 0.8 20
8279 142 4.0 1.3 119
* Standard deviation
678 9 4.2 0.7 10
1632 23 4.7 0.9 23 504 7 5.0 0.6 7
1698 20 4.8 0.7 22 1692 19 5.0 0.8 21 1746 11 4.0 0.7 24
8279 93 4.7 0.8 113
16558 235 4.3 1.1 232
Contractor's tests
Average [ S.D.* (%) (%)
3.8 O.6 3.6 0.5 3.8 0.7 3.7 0.7 3.9 0.8 3.8 0.6
3.8 0.6
4.3 0.7
4.0 0.8 4.7 0.6 4.5 0.8 4.3 0.6 4.0 0.6
4.2 0.7
4.0 O.7
9
TABLE 6
Summary of concrete density measurements
Section
WESTBOUND CARRIAGEWAY
280 m m Unreinforced
210 m m CRCP-fabric reinforced
280 m m Reinforced
230 m m CRCP-mid-depth
250 m m CRCP-third-depth
250 m m CRCP-mid-depth
Complete carriageway including transitions
EASTBOUND CARRIAGEWAY
280 m m Unreinforced with narrow joints
280 m m Unreinforced
280 nun Reinforced
210 m m CRCP-third-depth
210 m m CRCP-mid-depth
230 m m CRCP-third-depth
Complete carriageway including transitions
BOTH CARRIAGEWAYS
300 m m long cylinders 150 mm long
cylinders
7 day tests 28 day tests 28 day tests
Average Average No. No. (kg/mJ) No. (kg/m3)
16
24
7
23
24
22
126
10
23
7
22
22
24
114
Average (kg/m ~)
2340 16
2364 42
2344 14
2356 14
2350 48
2354 42
2352 225
2345 10
2347 23
2323 7
2331 22
2316 22
2315 24
2329 114
2341 339
2342
2362
2356
2360
2354
2355
2356
2343
2342
2325
2339
2319
2318
2331
2348
40
14
46
48
40
202
240
2362
2359
2362
2362
2361
2362
10
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c ~
~ 0
c ~
0 0
O~
0
~ 0
c ~
o = o 0
l l
Table 6 shows that densities in the second (Eastbound) carriageway were slightly lower probably because of
the increased air content; the higher density measured in the 150 rnm long cylinders possibly indicates that better
compaction was achieved in these specimens than in the 300 mm long cylinders.
All the concrete strength tests for both carriageways and hardshoulders complied with the specification. The
reduced 7 and 28 day strength results obtained on the second (Eastbound) carriageway were the result of the
higher level of entrained air. The variability of the concrete, as evidenced by the coefficients of variation, was
higher than would be expected on a large contract; the explanation for this is probably that control of concrete
quality was effected by means of the Slump Test which is insensitive for controlling workability of PQ concrete.
3.2.2.1 Cores: A total o f 94 cores was taken from the carriageway slabs to check the depth and state of
compaction of the concrete and, where appropriate, the positions of reinforcement, dowel and tie bars. The
concrete in all the cores was well compacted, even in one 450 mm deep taken from above a keyway in one of the
anchorages. The average excess of slab thickness over that specified was 10 mm and all the cores showed thicknesses
within the tolerance allowed (15 mm less than nominal). The slab thicknesses of the experimental sections and
reinforcement depths, where appropriate, are summarised in Table 8. The position of the reinforcement appears
to be lower than intended; this is discussed in Section 5.1.2.
TABLE 8
Summary of core results
Section
Slab thickness Reinforcement depths
No. Average Max. Min. of Specified Average Max. Min.
(mm) (mm) (mm) (rnm) (mm) (mm) (mm) cores
No.
of cores
WESTBOUND CARRIAGEWAY
280 mm Unreinforced 14 290 317 265
210 mm CRCP-fabric reinforcement 11 234 255 225 10 105
280 mm Reinforced 2 285 295 275 1 60
230 mm CRCPomid-depth 12 234 270 215 8 115
250 mm CRCP-third-depth 11 256 270 237 11 90
250 mm CRCP-mid-depth 13 250 265 235 13 125
EASTBOUND CARRIAGEWAY
280 mm Unreinforced with narrow 3 313 332 275
joints
280 mm Unreinforced 4 288 298 280
280 mm Reinforced 2 295 305 285 2 60
210 mm CRCP-third-depth 4 220 227 212 3 75
210 mm CRCP-mid-depth 4 233 245 210 4 105
230 mm CRCP-third-depth 4 236 248 230 2 80
125
65
126
96
125
68
85
122
90
145 115
155 105
110 80
140 107
75
100
140
113
60
75
100
77
12
3.2.3 Surface characteristics
3.2.3.1 Surface regularity: The specified tolerances for longitudinal surface regularity were those in the Ministry
of Transport Specification 2, ie up to 20 irregularities are permitted to exceed 3 mm, up to 2 irregularities to exceed
6 mm and none to exceed 10 mm in a length of road of 300m, as measured by the rolling straight-edge. During
the currency of the contract the revised Department of Transport Specification 3 was published in which the 3 mm
and 6 mm tolerances were raised to 4 mm and 7 mm respectively. The results of the rolling straight-edge tests are
summarised in Table 9 in terms of both specification tolerances. These results show poor comphance with the
earlier specification but relatively good compliance with the later one. The results have not been analysed in the
different experimental sections because the effect of 'reinforcement ripple', discussed in Section 5.1.3, cannot be
readily detected by the rolling straight-edge.
TABLE 9
Summary of roiling straight-edge tests
Carriageway
WEST- BOUND
EAST- BOUND
Lane
Left- hand
Centre
mght- hand
All
Left- hand
Centre
mght- hand
All
Length* tested (m)
2920
8278
1120
12318
2800
6941
4471
14212
No. of runs*
10
31
4
45
10
24
16
50
DOE Specification
No. passing
3
9
2
14
Per cent
30
29
50
31
10
54
19
34
DTp Specification
No. passing
9
28
4
41
1
13
3
17
7
20
9
36
q Per cent
90
90
100
91
70
83
56
72
BOTH , All I 26530 : 95 1, 31 33 77 81
* Length of run was generally 300m but some lengths were tested twice.
Three additional methods of measuring the surface profile were used to assess the riding quality of the surface.
The surface irregularity indices, q, obtained by the multi-wheeled prof'flometer are shown in Figure 5. Taking an
index, q, of 65 cm/km or less as indicating a very good quality of ride 4, 41 out o f the 70 measurements (58 per
cent) fall within this category and only 7 measurements (10 per cent) have an index of greater than 120 cm/km;
this would be classed as fair.
Two other methods of measuring surface irregularity, the High-Speed Profilometer, developed at TRRL 5,
and the Bump Integrator, were also used; the results obtained are given in Table 10.
13
TABLE 10
Results obtained using the high-speed profilometer and bump integrator ('r' value)
Section
WESTBOUND CARRIAGEWAY
280 mm Unreinforced
210 mm CRCP-fabric reinforcement
280 mm Reinforced
230 mm CRCP-mid-depth
250 mm CRCP-third-depth
250 mm CRCP-mid-depth
EASTBOUND CARRIAGEWAY
280 mm Unreinforced with narrow joints
280 mm Unreinforced
280 mm Reinforced
210 mm CRCP-third-depth
210 mm CRCP-mid-depth
230 mm CRCP-third-depth
Lane
Left-hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre
Left-hand Centre
Left hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre Right-hand
Left-hand Centre
Left-hand Centre
r
(cm/km)
197 222
150 152
205 216
158 174
177 193
161 167
189 194
170 178
193 219
170 178
182 177
215 196
3m [ 5m (mm) (mm)
0.79 0.93 0.96 1.17 0.91 1.09
0.61 0.85 0.63 0.84 0.63 0.82
0.81 0.94 0.95 1.06 0.95 1.09
0.68 0.84 0.76 0.91 0.80 0.95
0.83 1.05 0.88 1.08
0.65 0.79 0.72 0.87
0.79 0.91 0.80 0.95 0.83 0.92
0.73 0.89 0.82 1.01 0.85 1.04
0.79 0.97 0.86 1.03 0.86 1.05
0.74 0.96 0.81 1.06 0.83 1.10
0.83 0.87 0.77 0.98
0.96 1.17 0.96 1.29
Standard deviation under moving average lengths of:
I (run)
1.12 1.39 1.31
1.16 1.37 1.30
1.27 1.35 1.44
1.17 1.26 1.28
1.37 1.49
1.18 1.24
1.14 1.25 1.25
1.15 1.36 1.44
1.38 1.36 1.39
1.55 1.62 1.73
1.20 1.45
1.66 2.02
The bump integrator readings show that none o f the experimental lengths are 'very good' ('r' less than
145 cm/km) but 20 o f the readings (83 per cent) are less than 210 cm/km and are considered to be 'good'. With
two exceptions all the results hldicate a lower value for the left-hand lane than for the centre lane.
14
In assessing the results from the High-Speed Profdometer it has been assumed that a moving-average length o f
3m provides a profde datum that approximates to that of the rolling straight-edge and experience has shown that a
standard deviation of the profde about this datum of less than 1 mm indicates compliance with the Department of
Transport's straight-edge specification 3. On this basis all the sections would be acceptable; again the near-side lane
tends to have the lowest values, ie the best riding qualities. All the measures of irregularity so far considered are
related to relatively short wave lengths. The standard deviations of the profde about a moving average of 10m are a
measure of longer wave lengths and the results given in Table 10 again show the left-hand lane to have the lowest
values.
From the various irregularity measurements, the best riding quality occurred on the 210 mm thick CRCP
section with fabric reinforcement, followed by the 250 mm and 230 mm thick CRCP sections with reinforcement
at mid-depth. The worst riding qualities were given by the two jointed reinforced sections and the 250 mm thick
CRCP section with reinforcement at third-depth, worst of all being the 230 mm thick CRCP section with
reinforcement at third-depth. The effect of reinforcement on surface regularity is discussed in Section 4.1.3.
It was anticipated that the unreinforced section with narrow unsealed transverse joint grooves would have a
superior riding quality to that of the unreinforced sections with normal width wet-formed joint grooves. This has
not proved to be the case because, although the values for the section with narrow grooves are better than those
of the unreinforced section on the Westbound carriageway (including the trial length), they are not as good as
those for the longer unreinforced section on the Eastbound carriageway. This indicates that wet-formed joints can
be formed and recompacted without detriment to the riding qualities of the slab.
3.2.3.2 Surface texture: The Specification requirement for surface texture 2 was that the average value for each
set of 10 sand-patch tests should be not less than 0.75 mm and that there should be not more than one test of each
set with a value of less than 0.65 mm. The results of the tests made on the carriageway slabs are given in Table 11 ;
most of the tests were made on areas where there were doubts about the texture.
TABLE 11
Results of surface texture measurements (on doubtful areas)
Carriageway
WESTBOUND
EASTBOUND
BOTH
No. of test sets
37
38
75
No.
27
26
53
%
73
68
71
Passing Average texture depth (mm)
1.01
0.94
0.97
Approximately one-third of the values failing to meet the specification were the result of the average value
being less than required; the minimum average value for texture depth was 0.57 mm.
15
3.3 Concrete slabs in hardshoulders
3.3.1 Plastic concrete: The results of the Slump Tests are given in Table 12.
TABLE 12
Summary of Slump Test results on hardshoulder concrete
Client's tests Contractor's tests
Carriageway l No. Average S.D.* No. Average S.D.*
(mm) (mm) (mm) (mm)
WESTBOUND
EASTBOUND
BOTH
56
44
100
28.8
24.8
27.0
16.4
11.9 14.7
65
56
121
25.5
22.0
23.9
10.4
9.8
10.2
* Standard deviation
The concrete used in the hardshoulders had very similar workabilities, as measured by the Slump Test, to
that used in the carriageways (see Table 4) but with reduced variabilities.
A summary of the air content test results is given in Table 13.
TABLE13
S u m m a r y o f a i r c o n t e n t t e s t r e s u l t s ~ r h a r d s h o u l d e r c o n c r e t e
Carriageway
WESTBOUND
EASTBOUND
BOTH
No.
50
43
93
Client's tests
I Average (%)
4.7
4.2
4.5
S.D.* (%)
0.9
0.9
0.9
* Standard deviation
No.
65
56
121
Contractor's tests
Average S.D.* (%) (~)
4.4 0.9
3.8 1.0
4.1 1.0
3.3.2 Hardened concrete: For the hardshoulder concrete only cylinders 150 mm diameter and 300 mm long were
used. The density results are summarised in Table 14 and the indirect tensile strength tests are summarised in
Table i 5.
16
TABLE 14
Summary of density measurements on concrete for hardshoulder
Carriageway
WESTBOUND
EASTBOUND
BOTH
No.
65
56
121
7 day tests
Average (kg/m ~ )
2311
2335
2322
No.
65
50
115
28 day tests
Average (kg/m ~)
2317
2343
2328
TABLE 15
Summary of indirect tensile strength results o f hardshoulder concrete
Carriageway No.
WESTBOUND 65
EASTBOUFrD 56
BOTH 12 l
* Standard deviation ** Coefficient of variation
7 day tests
Average S.D.* C.V.** (N/mm 2) (N/mm 2) (%)
2.58
2.85
2.70
0.31
0.32
0.35
12.0
11.2
13.0
No.
65
56
121
28 day tests
Average S.D.* C.V.** (N/mm 2) (N/mm 2) (%)
3.01
3.15
3.07
0.36
0.28
0.34
12.0
8.9
11.1
The densities of the concrete were similar to those of the concrete in the Eastbound carriageway; the average
tensile strengths at both 7 and 28 days for the Eastbound hardshoulder were very similar to those for the Eastbound
carriageway but the strengths obtained from concrete in the Westbound hardshoulder were somewhat lower. The
variability of concrete strengths was less than that observed in the carriageway paving.
3.3.3 Surface characteristics
3.3.3.1 Surface regularity: The regularity requirements of the specification for the hardshoulders were less
rigorous than those for the carriageway; no measurements were made.
3.3.3.2 Surface texture: The surface of the hardshoulders was textured by transverse brushing with a wire broom.
The specification contained no minimum texture-depth requirements.
4. REMEDIAL ACTIONS
In Section 3.2.3, mention was made of non-compliance with the surface regularity and texture requirements of
the specification. Remedial action was taken to improve the riding quality and resistance to skidding over only
0.45 per cent of the paved area. Regularity was improved by 'bump cutting' using a small flailing machine to
remove highspots; six short lengths were treated. The same machine, with the flails arranged to form random
spaced transverse grooves, was used to retexture the areas of low texture depth.
17
At ten joints in the hardshoulder, alongside the conventionally reinforced section in the Westbound carriage-
way, there was a delay in sawing the joint grooves and uncontrolled cracking resulted. Where the cracks were more
than 200 mm away from the centre-line of the joint, they were repaired using the accepted method of inserting
dowel bars. Where the joint grooves were required to be wider than 10 mm, at expansion joints and at the
contraction joints alongside the conventionally reinforced sections, the initial saw cut was subsequently widened.
5. COMMENTS ON CONSTRUCTION
No abnormal difficulties were experienced during the construction of the CRCP sections either by the contractor
or by the client. As in all paving work, good pre-planning and an efficient organisation are necessary if paving is to
proceed rapidly and to specification. In the M 180 neither the anchorages nor the wide-flange beam joints posed
difficulties, although the latter required very careful setting-out to ensure that the beams were at the correct level.
In a CRCP road the reinforcement needs to be positioned well ahead of the paving operation; similarly, in a
jointed pavement the transverse joint assemblies must be erected and tested well in advance of paving when a slip-
form paver is used. For the experirnental sections the average forward speed of the slip-form paver was approx-
imately 1.0m per minute. The lowest average speed achieved was 0.5m per minute for the unreinforced section on
the Westbound carriageway (this included the trial lengths). The fastest progress was in the 210 mm thick CRCP
section with mid-depth reinforcement for which the average speed was 1.3m per minute (this included the record
daffy output of 1132m). Obviously, the rate of paving is influenced by weather conditions and the distance of the
paving site from the hatching plant but if the overall rates of progress are examined, ie including joint forming,
texturing and application of curing compound, the rates are generally higher for the CRCP sections than for the
jointed paving.
5.1 Tolerances
5.1.1 Slab thickness: The slab thicknesses deduced from dip measurements made before and after paving, at 2m
intervals across the carriageways from wires spaced at 6 metre hatervals along the carriageways, showed close
agreement with the nominal thicknesses. The core results (Table 8), however, indicated thicknesses somewhat
greater than those specified. The reasons for this difference cannot be explained; however the cores represent
a very small proportion o f the carriageway area and may be unrepresentative.
5.1.2 Reinforcement position: In all, 51 cores were taken from the CRCP sections. A tolerance of + 10 mm
was permitted in the Specification for experimental purposes and in 26 (51 per cent) of the cores, the reinforcement
was outside the tolerances allowed.
In a system of construction using free-standing reinforcement the position of the steel and its tolerances will
normally be governed by the accuracy of the sub-base levels and reinforcement supports; in the M180 specification,
the tolerances for sub-base levels were + 20 mm. A contractor using free-standing reinforcement must either ensure
that the accuracy of laying of the sub-base is to the tolerances required for the reinforcement or ensure that the
reinforcement level is a fixed distance below theoretical pavement level by adjusting the supports. Had the
reinforcement been specified in this instance as a certain height above the base of the slab, then in only 7 (14 per
cent) o f the cores would it have been outside the tolerances of + 10 mm.
18
5.1.3 Reinforcement ripple: This effect, mentioned earlier in Section 3.2.3.1, is the reflection on the finished
slab surface of the pattern of the reinforcement in the form of shallow depressions, usually less than 3 m m in
depth. The exact cause of reinforcement ripple is not fully understood but it is believed to be due to further
vibration transmitted to the reinforcement after the passage of the paver; this extra vibration, o f a high frequency,
causes further consolidation of the concrete immediately above the reinforcement bars or wires and thus the
depressions in the surface.
The depressions above the longitudinal bars do not cause any inconvenience to traffic but those above the
transverse bars, because of their regular spacing, can initiate vibrations in vehicles which at certain speeds induce
drumming. The presence of reinforcement ripple can be detected by the m~dti-wheeled and high-speed
profdometers and examples of profiles obtained from the latter machine are shown in Figure 6.
The occurrence of ripple is influenced by a number of factors; these include direction, amplitude and frequency
of the applied vibration in the paver, depth of reinforcement, diameter and spacing of the bars, and workability
of the concrete. Ripple can occur with conventional reinforced pavements as well as in CRCP and it is present in
the conventionally reinforced concrete sections of M180.
The possibility of ripple occurring was considered beforehand and for this reason the specification required
the transverse bars to be placed beneath the longitudinal reinforcement. A detailed analysis of reinforcement ripple,
and the factors causing it on this section, has not been possible because no measure of ripple was available, there
was little information on reinforcement depth and because the Slump Test was insensitive as a measure o f work-
ability. A regression analysis of the average reinforcement depth in the CRCP sections (from the cores) against the
standard deviation under a moving 3m length showed the relationship to be significant at between the 5 and the 10
per cent levels; the standard deviation decreased with increasing depth of reinforcement.
Subjectively, the worst lengths for reinforcement ripple are at the eastern ends of bo th carriageways. Here,
extra 16 mm diameter deformed bars were placed across the top of the bar mats to strengthen the slabs against
the expected settlement over an area of peat; also at the eastern end of the Eastbound carriageway the bar mats
were inverted with the transverse bars on top so that a longitudinal joint groove of adequate depth could be formed.
As a result o f the occurrence of ripple the design recommendations for future CRCP have been amended
to specify a closer spacing of smaller diameter bars for transverse reinforcement.
5.1.4 Omission of separation membrane: The occurrence of cracking at the joints in the unreinforced section
with narrow unsealed transverse joint grooves was monitored to observe whether the omission of the separation
membrane had an effect on the rate of cracking. At 3 days, 35 per cent o f the joints where there was no membrane
had cracked compared with 25 per cent of the joints where the membrane was included; at 14 days the respective
percentages were 50 and 44. This limited evidence suggests that the omission of the membrane promotes earlier
cracking at the transverse joints; this should be associated with a more uniform joint movement during the life
of the pavement.
19
6. COSTS
When a large number of variables are incorporated in a full-scale experiment, costs are likely to be masked by the
need for changes in thickness and materials. The tender rates for the six contractors have been compared in Table 16
on the basis that the control sections of 280 mm thick unreinforced slabs with sealed joints have a value of 100;
the comparison includes the tender rates for sub-bases.
TABLE 16
Comparison of tender rates for different forms of construction
Construction type
280 mm Unreinforced
280 mm Unreinforced with narrow joints
280 mm Unreinforced with narrow joints no underlay
280 mm Reinforced
210 mm CRCP fabric reinforcement
210 mm CRCP bar mat reinforcement
230 mm CRCP bar mat reinforcement
250 mm CRCP bar mat reinforcement
1
100
99.7
99.1
110.2
104.2
106.4
114.2
118.0
Tender rates for contractor
2
100
97.7
96.6
116.6
118.7
121.6
126.6
132.3
3
100
100.0
99.3
109.2
121.4
124.2
127.9
130.8
4
100
103.0
102.4
110.9
118.7
121.1
127.7
131.0
5
100
98.8
97.8
116.5
124.9
127.4
125.2
126.3
6
100
99.6
98.3
124.8
140.9
142.6
149.8
154.1
Average
100
99.8
98.9
114.7
121.5
123.9
128.6
132.1
As was to be expected, there was a wide divergence in the actual tender rates submitted by the six contractors
but all priced the 250 mm CRCP as the most expensive and, with one exception, the 280 mm unreinforced with
narrow joint grooves and no separation membrane as the cheapest. Contractor 4 obviously priced joifat sawing
much higher than the other contractors; it is not known how the contractors other than the successful one intended
to carry out the work. The difference between jointed unreinforced and CRCP construction will reflect the relative
prices o f concrete and steel. On the basis o f the M180 prices it would appear that, for a steel content of 0.6 per
cent, a 70 mm reduction in slab thickness for CRCP will cost between 5 and 20 per cent more than a conventionally
jointed unreinforced pavement; for a 50 mm thinner CRCP slab, the extra paving cost will be between 15 and 30
per cent and for a 30 mm thinner CRCP slab the extra cost will be between 20 and 35 per cent.
More realistic costs of CRCP will be obtained from normal contracts without experimental variations.
7. PERFORMANCE
Paving of the carriageways was completed on 5 August 1978 and that of the hardshoulders by 15 September 1978.
The western half of the section, ie up to the A161 interchange was opened to traffic in October 1978 and the
remaining length was opened on completion of the Trent Bridge in July 1979.
20
Performance of the CRCP sections will be assessed from crack surveys made at regular intervals; early
indications are that the optimum average spacing of transverse cracks of between 1.5 and 2.5m will be achieved.
8. ACKNOWLEDGEMENTS
The work described in this report forms part of the research programme of the Construction and Maintenance
Division (Division Head: Mr P D Thompson) of the Highways Department of TRRL.
The willing co-operation of the staff of the West Yorkshire Metropolitan County Council Sub-Unit (Chief
Engineer: Mr J A Gaffney) and of Sir Alfred McAlpine and Son (Northern) Limited is very gratefully acknowledged.
9. REFERENCES
1. GREGORY, J M. The design of experimental concrete carriageways on M180 (Sandtoft to Trent Section).
Department of the Environment Department o f Transport, TRRL Report SR 653. Crowthorne, 1981
(Transport and Road Research Laboratory).
. MINISTRY OF TRANSPORT. Specification for road and bridge works. Fourth edition. London, 1969
(H M Stationery Office).
. DEPARTMENT OF TRANSPORT. Specification for road and bridge works. Fifth edition. London, 1976
(H M Stationery Office).
4. DEPARTMENT OF TRANSPORT, TRANSPORT AND ROAD RESEARCH LABORATORY and
CEMENT AND CONCRETE ASSOCIATION. A guide to concrete road construction (Third edition).
London, 1978 (H M Stationery Office).
5. DEPARTMENT OF THE ENVIRONMENT DEPARTMENT OF TRANSPORT. Transport and Road
Research 1976. Annual Report of the Transport and Road Research Laboratory. London, 1977
(H M Stationery Office).
21
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Neg. no. R132/80/11
Plate 1 Guntert and Zimmerman slip-form paver laying 3-lane carriageway (The section being laid is 280mm thick reinforced jointed pavement)
Neg. no. R 132/80/4
Plate 2 Completed reinforcement showing ring spacers in use. (Section is 210mm thick CRCP with mesh fabric reinforcement)
Ne9. no. R132 /80 /13
Plate 3 Small G & Z slip-form paver laying hardshoulder and integral trapezoidal drainage channel
( 1 5 6 2 ) D d 8 0 4 1 3 0 1 1 , 5 0 0 9 /81 l - tPL td So ' t ( )n ( 3 1 9 1 5 P R I N T E D IN E N G L A N D
ABSTRACT
THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION): J M Grego~ FIHE: Department of the Environment Department of Transport, TRRL Supplementary Report 682: Crowthorne, 1981 (Transport and Road Research Laboratory). This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of the experiment has been reported in SR 653.
Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output o f 502m was achieved. The hard- shoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.
The results of tests on the plastic and the hardened concrete are reported, together with summaries of the results of tests on the finished surfaces.
ISSN 0305-1315
ABSTRACT
THE CONSTRUCTION OF EXPERIMENTAL CONCRETE CARRIAGEWAYS ON M180 (SANDTOFT TO TRENT SECTION): J M Gregory FIHE: Department of the Environment Department of Transport, TRRL Supplementary Report 682: Crowthorne, 1981 (Transport and Road Research Laboratory). This report describes the construction of the experimental concrete carriageways on the Sandtoft to Trent section of M180; the design of the experiment has been reported in SR 653.
Construction of the 11.2m wide concrete carriageways was carried out in one operation by a slip-form paver. The maximum length laid in one day was 1132m and an average daily output o f 502m was achieved. The hard- shoulder was also paved in concrete by a small slip-form paver which formed the integral drainage channel.
The results of tests on the plastic and the hardened concrete are reported, together with summaries of the results of tests on the finished surfaces.
ISSN 0305-1315