Influence of Mixing Procedure and Mixer Type on Fresh

Influence of mixing procedure and mixer type on freshand hardened properties of concrete: a review

J. Dils • G. De Schutter • V. Boel

Received: 8 December 2011 / Accepted: 17 April 2012 / Published online: 10 May 2012

� RILEM 2012

Abstract Mixing concrete is not yet a fully under-

stood issue, with many parameters having an influence

on the resulting fresh and hardened concrete proper-

ties. Even for the same composition, a somewhat

different microstructure can be obtained by changing

the mixing procedure and the mixer type. A mixing

procedure can differ in mixing time, mixing speed, air

pressure in the mixing pan, addition time of the

superplasticizer, temperature, etc. The concrete indus-

try shows a great interest in controlling these influ-

ences in order to produce a concrete of which the

mechanical, rheological and durability properties are

well known. In this overview, different concrete

mixers, mixing times, mixing speeds, different addi-

tion times of the superplasticizer and a different air

pressure in the mixing pan will be examined. A review

of existing literature is presented, as well as some new

experimental results.

Keywords Concrete mixers � Mixing time �Mixing speed � Air pressure � Temperature �Addition time of SP

1 Introduction

For the concrete industry and concrete research

institutes it is of importance to determine the quality

of the concrete produced. In many cases the concept of

‘‘mixer efficiency’’ is used to qualify how well a mixer

produces a uniform concrete from its constituents [11].

According to RILEM [2] a mixer is efficient if it

distributes all the constituents uniformly in the con-

tainer without favoring one or the other. Therefore, in

evaluating the mixer efficiency, properties such as

segregation and aggregate grading throughout the

mixture should be monitored. DIN EN 206-1 [9]

propose three classes: ordinary, performance or high-

performance mixers. Each class is defined by the

obtained variability of four main parameters (water-

to-fine ratio, fine content, coarse aggregate content, air

content). Several samples are taken from the mixer

and for each parameter the average and standard

deviation is calculated. The coefficient of variation

gives a measure of the homogeneity of the concrete

produced. Nold [18] shows that an intensive mixer

with a rotating pan has the lowest variation coefficient

in comparison with the other mixers. In order to

increase the efficiency of a mixer, a study of the main

parameters is of great value. Another way to indicate

the efficiency of a mixer is followed by Williams et al.

[24] and Yang and Jennings [25]. The structure left in

a paste after mixing can be evaluated by the plastic

viscosity, the hysteresis area or the peak stress which is

obtained by a simple rheometer test. This remaining

J. Dils (&) � G. De Schutter

Magnel Laboratory for Concrete Research,

Ghent University, 9000 Ghent, Belgium

e-mail: [email protected]

V. Boel

Department of Construction, Faculty of Applied

Engineering Sciences, University College Ghent,

9000 Ghent, Belgium

Materials and Structures (2012) 45:1673–1683

DOI 10.1617/s11527-012-9864-8

structure also gives an indication of the efficiency of

the mixer. The more agglomerates remain in a paste

after mixing, the less efficient the mixer is.

2 Concrete mixers

Concrete mixers can be divided in two main groups: a

batch mixers and continuous mixers. A batch mixer

can produce one batch at the time and has to be

emptied completely after each mix. Two main types

can be distinguished. A drum mixer has a horizontal or

inclined axis of rotation. It has fixed blades to lift the

materials as the drum rotates. The rotation speed of the

drum can be controlled and sometimes the inclination

of the axis also. The pan mixer, with a vertical axis of

rotation has a cylindrical pan (fixed or rotating) which

contains the concrete. One or two blades rotate inside

the pan to mix the materials, while another blade

scrapes the wall of the pan. The shapes of the blades

and the axes of rotation can vary. If the pan is fixed, the

scraper must move to push the concrete towards the

blades. A continuous mixer produces concrete at a

constant rate. The materials are continuously fed into

the mixer at the same rate as the concrete is

discharged. Screw type blades rotating in the middle

of the drum. Interesting research towards the effi-

ciency of this type of mixer can be found in the work of

Yubakami et al. [26].

At the Magnel Laboratory, a planetary mixer

(Fig. 1e) and an intensive mixer (Fig. 2) are com-

monly used, to produce conventional vibrated con-

crete (CVC), self-compacting concrete (SCC) and

ultra high performance concrete (UHPC). The Eirich

mixer, of which the principle was invented in 1924,

separates the materials transport from the actual

mixing process. A rotating pan transports the

material to be mixed and an eccentrically mounted

tool performs the mixing function. This principle

gives some advantages compared to the planetary

mixer [18]:

Fig. 1 Various

configurations for pan

mixers. The arrows indicate

the direction of rotation of

the pan, blades, and scraper

[11]

1674 Materials and Structures (2012) 45:1673–1683

• In the intensive mixer there is no scraping of the

material over walls and bottom. Because the

mixing pan transports the materials to the mixing

tool, there is no speed differences between the pan

wall/bottom and the materials. In the mixer with

inclined pan there is one bottom/wall scraper

where friction may occur. Near the scraper, the

particle velocities are quite low, and independent

from the speed of the rotor tool. The rotor can work

at any speed without increasing friction, and wear

near the scraper.

• The added quantities of admixtures can often be

reduced because of the better mixing process. The

same can be said about the amount of cement and

water, which can be reduced without lowering the

consistency in comparison with the planetary

mixer.

Besides the better mixing principle, many parameters

can be varied to investigate their influence on the

properties of the concrete. The tool speed can be

adjusted over a wide range and the mixing time is

independent of the mixer size. Therefore the energy

input into the product is specifically adjustable to the

product. The sense of rotation of the rotor can be

selected and the mixing quality is almost independent

of the filling level.

3 Mixing time

According to Beitzel [1] the optimal mixing time of a

pan mixer varies between 30 and 180 s. Schiessl et al.

[20] relate the mixing time to a certain stabilisation

time, which depends on the composition of the

concrete and the mixing speed applied during the

procedure. They characterize the mixing time by three

phases (Fig. 3).

• Phase 1 Dispersion: Water is distributed in the

mix. Due to the surface tension of the water and the

capillary pressure inside the water, the forces

between the particles increase and a significant

increase of the power is needed to distribute the

water and superplasticizer. The slump flow

increases as the distribution improves. The evolu-

tion of this improvement in a concrete truck can be

seen in Fig. 4. The concentration of superplasti-

cizer in the cement–water solution increases with

the mixing time [5].

• Phase 2 Optimum: The power decreases towards a

plateau were the components are homogeneously

mixed and the superplasticizer is fully distributed.

The slump flow reaches its maximum.

• Phase 3 Overmixing: For UHPC the slump flow

remains rather constant after reaching the opti-

mum. For SCC on the other hand the slump flow

decreases due to the number of fine particles in the

mix that is raised by abrasion of the coarse

Fig. 2 Intensive mixer (75 l)

Fig. 3 Effect of the mixing time on the power and the slump

flow [14]

Materials and Structures (2012) 45:1673–1683 1675

aggregate. As a consequence new surfaces are

produced for reaction, increasing the demand of

superplasticizer and reducing the slump flow.

Diawara and Ghafoori [5] also encountered this

phenomenon by investigating the change in parti-

cle size distribution with a laser diffractometer in

function of the mixing time. It can be seen from

Fig. 5 that the volume of fine particles ranging

from 1 to 250 lm increased as the hauling time

increased.

The main purpose of this interpretation is to limit the

actual mixing time (Fig. 6) for SCC (±4 min) and

UHPC (±12 min). As a consequence the rate of

concrete production will become more competitive to

that of CVC and an important financial disadvantage

for high performances concrete types will be dimin-

ished. Figure 7 shows that with an intensive mixer a

similar interpretation for CVC is possible. The work-

ability also rises till an optimum and decreases due to

overmixing. From these figures it can be seen that the

composition of the concrete plays an important role.

For each type a specific optimal mixing time exists,

called the stabilisation time.

The stabilisation time is calculated based on the time-

power curve. According to Mazanec et al. [17] the

normalized power can be divided into two regions,

namely before and after peak power. The first region can

be fit by a linear function and the second by an

exponential function. According to Chopin et al. [3]

only the last region is of importance (Fig. 8) and can be

fitted mathematically by a similar exponential function.

Mazanec et al. [17] note that when the slope of

Fig. 8 has a value of approximately -0.004 the

mixture has reached an optimal workability and this

after a minimal mixing time and a constant mixing

speed (Fig. 9). The time corresponding with this slope

is called the stabilisation time ts. This argumentation

can not only be used for SCC and UHPC but also for

CVC. Own results, of which some are presented in

Fig. 7, indicate a stabilisation time for CVC between

45 and 70 s, depending on the water-to-cement ratio.

The influence of the concrete composition on the

stabilisation time can be taken into account by

the relative concentration of solids ///max, which is

the ratio of the actual concentration of solids in a

concrete mix / to the maximum possible concentra-

tion of solids /max obtained at the maximum packing

density of the particles [17]. The higher this value, the

more energy the mixer needs to properly disperse all

the components (Fig. 10). Altering the mass fractions

of each component can change the mixing time with

Fig. 4 Influence of hauling time on concentration of HRWRA

[5] Fig. 5 Particle size distribution of SCC at different hauling

times [5]

Fig. 6 Effect of the mixing time on the slump flow for SCC

[14]


several minutes. With an increase of the amount of

silica fume a shorter mixing time can be obtained. This

is explained by the gaps between the coarser cement

and quartz particles which are filled by more small

silica fume particles. The water which would

otherwise have filled the gaps is used to reduce the

friction between the particles. The spherical form of

the silica fume particles has the same effect and

thereby shortens the stabilisation time [17].

Chopin et al. [4] use the stabilisation time to predict

the mean compressive strength of their mixture after a

certain mixing time. When ts and the mean compres-

sive strength after extended mixing fc1 is known, fccan be calculated at the desired mixing time by Eq. (1).

fcðtmÞ ¼ fc1 1� ats

tm

� �� ð1Þ

a is a coefficient that depends on the mixer efficiency.

The slightly higher strengths that are found for

tm = 600 s are explained by the better homogeniza-

tion of the constituents. This depends again on the

efficiency of the mixer, as mentioned in Sect. 2. When

the standard deviation of the compressive strength for

a mixing time tm is taken into account, Chopin et al. [4]

conclude that the increase in strength is not significant

for short mixing periods. Research in the Magnel

Laboratory led to the same conclusion [6]. Takahashi

et al. [22] also made this observation for grouting

mortars, although the early compressive strength

increased after a mixing time of 7 min. Chopin et al.

[4] also investigated the influence of the mixer

capacity on the stabilisation time of different mixtures.

Figure 11 illustrates that, a shorter mixing time is

required for a higher mixer capacity. This conclusion

is correct for a planetary mixer, but normally not for an

intensive mixer, where the stabilisation time is inde-

pendent of the mixer capacity.

Fig. 7 Effect of the mixing time on the slump for CVC [7]

Fig. 8 Experimental and mathematical power curve [3]

Fig. 9 Calculation of the stabilisation time [3]

Fig. 10 Influence of the composition on the stabilisation

time ts [17]


4 Mixing speed

The tool speed also influences the mixing process and

thus the stabilisation time. Martinek [15] writes in

1984 that the most favorable mixing effect in a

cylindrical dual-shaft mixer, is obtained at tip speeds

of 1.5 up to 1.6 m/s. Geiker et al. [13] claim that for the

same SCC composition a longer mixing time is needed

to obtain equilibrium, when a lower mixing speed is

used.

Mazanec et al. [17] investigated the influence of the

mixing speed on the stabilisation time. The ultra-high

performance reference concrete, used in their inves-

tigation, reached a maximum power after 34 s at a

speed of 2.9 m/s and 48 s at a speed of 1.4 m/s. The

times needed to reach stabilisation of the mix after the

peak power were 150 and 142 s at 1.4 and 2.9 m/s.

Based on this result they optimized their mixing

procedure by mixing at high speed in the beginning in

order to distribute the water and the superplasticizer

rapidly (mixer). After the peak power, the mixing is

continued at low speed until the stabilisation time is

reached (transport). They also derived an Eq. (2) to

calculate the stabilisation time for their reference

UHPC mixture based on the applied mixing speed and

relative concentration of solids, ///max.

tm� ts ¼13:1� v�0:114

1� 1:0046� //max

ð2Þ

Dils et al. [6] have been investigating the influence

of the number of rotations on the workability of SCC

and self-compacting mortar (Figs. 12, 13). For con-

crete an intensive mixer with a capacity of 75 l is used,

while the mortar is prepared in an intensive mixer with

a capacity of 5 l. In both mixers the same circumfer-

ential speed at the tip of the vanes is used and the

conversion from concrete to mortar is done by

the CEM-method [21]. Hereby a comparison between

the two material levels is possible. Figure 12 shows

that for a high water-to-cement ratio an increase in the

number of rotations has no essential influence on the

slump flow. For lower water-to-cement ratios an

optimum is reached. When the number of rotations

is higher than this optimum, the workability drops due

to overmixing (Fig. 3). A water-to-cement ratio of

W/C = 0.40 seems to be less susceptible to overmix-

ing than a water-to-cement ratio of W/C = 0.46. This

slump loss is also confirmed by the research of Vickers

et al. [23].

A self-compacting mortar, shown in Fig. 13 is

apparently less sensitive to an increase in the number

of rotations. Only at a higher amount of rotations, the

Fig. 11 Mean stabilisation time as a function of mixer capacity

(non-intensive mixer types) [4] Fig. 12 Slump flow in function of the number of rotations [6]

Fig. 13 Mini slump flow in function of the number of rotations

[6]


mixer is able to break down the finer sand grains and

thus to reduce the workability as explained in Sect. 3.

Because the corresponding points in Figs. 12 and 13

represent the same amount of energy, it may be

concluded that when an optimal mixing time and

mixing speed is determined for concrete, the same

time and speed may be used for mortars.

5 Mixing sequence, material selection

and temperature

At the Magnel Laboratory for concrete research the

components (fine and coarse aggregates, fillers) are

discharged by a mobile scale into the mixing pan of the

intensive mixer (Fig. 14). This means that the mixing

sequence can not be varied with these elements. The

only thing that may be of interest is the manner and the

timing of addition of the superplasticizer. According

to Flatt and Houst [12] plasticizing admixture added

directly to the mixing water may be intermixed with

the early hydration products. If the addition of

plasticizer is delayed a few minutes, a major improve-

ment of the plasticizing effect is observed. Figure 15

shows that this remark holds true for self-compacting

mortars with high water-to-cement ratio and thus with

a smaller amount of superplasticizer. Namely, an

interference with the hydration products will be felt

more by a SCC mixture with less superplasticizer [6].

Mazanec and Schiessl [16] also claim that for each

cement there is an optimal addition time, depending on

the SO3 content of the cement. The superplasticizer

can be added earlier for cements with a high content,

because for such cements more superplasticizer will

be available for later adsorption on newly formed

hydration products and silica fume.

Another effect of the addition time can be seen in

Fig. 16, where the apparent viscosity is larger for

mixtures with a direct addition of SP than with a

delayed addition. The differences decrease by increas-

ing the amount of plasticizing admixture. The same

can be said about the thixotropy, static and dynamic

yield stress [10].

The type of superplasticizer also has an influence on

the addition time [16]. A superplasticizer with higher

anionic charge and molecular mass, with a longer

main chain, a higher density of side chains in the main

chain and shorter side chains, should be more mobile.

The reason is the fact that the motion of the

superplasticizer is restricted by long side chains and

low side chain densities. The superplasticizer will be

faster adsorbed so that less superplasticizer is

Fig. 14 Mixing sequence

Laboratory Magnel for

concrete research

Fig. 15 Influence of addition method of SP on the workability

of a self-compacting mortar (method 1: SP and water are mixed

in advance, method 2: first water and directly after SP, method 3:

first water, mixing 30 s, addition SP [6])


available for adsorption, for example on silica fume, at

a later stage. Such a superplasticizer has an earlier

addition time but results in a lower workability after a

certain time.

The type of cement also plays an important role

towards the workability of a certain mixture [16].

Cement with a lower C3A content and Blaine fineness

gives a more fluid mixture (Fig. 17). The reason is that

the degree of adsorption of SP, and thus the required

dosage, increases with the C3A content and fineness.

Another parameter that needs attention is the

environmental temperature. Cement pastes undergo a

change in flow behavior at different temperatures

(Fig. 18) [10]. It can be observed that, while viscosity

(slope of the flow curve) is substantially affected by

temperature, values of the yield stress (ordinate at zero

shear rate) show little variation, especially in the case

of upwards flow curves. Research of Takahashi et al.

[22] (Fig. 19) shows some inconsistent results with

Fig. 18. Here the workability of mortars is also

affected by temperature, but by lowering the temper-

ature during mixing a higher slump flow is obtained

after a mixing time of 7 min.

6 Influence of the pressure in the mixing pan

Concrete plants and laboratories are typically not able

to fully control the air while mixing. It is know that air

bubbles introduced in the concrete can affect the

compressive strength, change the workability and

Fig. 16 Apparent viscosity

at 40 s-1 from the upwards

shear rate ramp as a function

of SP dosage prepared by

direct (a) and delayed

(b) addition of SP [10]

Fig. 17 Paste flow after 3.5 min in dependence of superplast-

icizer (PCE 1) dosage for different Portland cements [16]

Fig. 18 Influence of different temperatures on the flow curve

(upwards flow curves are depicted in solid lines and symbols;

downwards flow curves are depicted in dashed lines and emptysymbols [10])


decrease the durability. Therefore it is of interest to

investigate the influence of the pressure in the mixing

pan. In order to do so, two intensive vacuum mixer

with capacity of 5 and 75 l are used in the Magnel

Laboratory. Both mixers have the possibilities to alter

the pressure from normal air pressure (about

1,013 mbar) to about 50 mbar. Figure 20 shows an

increase in compressive strength for UHPC, prepared

in the 5 l mixer, when the pressure is lowered from

1,000 to 50 mbar [8, 19]. The lower air content and

higher density decrease the number of defects and

increase the strength of the mortar. This effect is

similar for UHPC mixtures prepared in the larger

mixer (75 l), although less pronounced (Fig. 21). The

air content decreases from 6.7 % for 1,024 mbar to

4.6 % for 55.6 mbar. The compressive strength in

latter case was determined on cubes with side 15 cm.

Mazanec and Schiessl [16] also show that a reduced

pressure during the last minute of mixing considerably

improves the workability of the mortar due to the

reduction in air content. The decrease of air content

leads to an increase in slump flow due to a decrease of

the yield stress [27] (Fig. 22). This phenomenon is

also noticed in the research program at the Magnel

Laboratory. Using the larger mixer, it is found to be

less pronounced than for the smaller mixer (Fig. 23),

even though the air content decrease from 6.7 to

4.6 % [8].

Fig. 19 Influence of temperature on the slump flow of mortars

[22]

Fig. 20 Effect of pressure in a 5 l mixer on density and

compressive strength [19]

Fig. 21 Effect of pressure in a 75 l mixer on the compressive

strength of UHPC [8]

Fig. 22 Air void and flow of mortar in dependence of applied

pressure [10]


Furthermore the properties of fresh and hardened

concrete can also be affected by the duration of the

reduced pressure. Mazanec and Schiessl [16] conclude

that after 30 s it was possible to reduce the volume of

air voids in the UHPC mix to 1 %, using a 5 l intensive

mixer. Extending the duration yielded only a small

increase in compressive strength. The mortar flow

increased to a maximum around 60 s.

7 Conclusions

During mixing of concrete, several parameters influ-

ence the resulting fresh and hardened concrete prop-

erties. Based on available literature, a review has been

presented, as well as some newly obtained experi-

mental data. The following summary can be given:

• Intensive mixers operate following an improved

mixing principle, making them more suitable to

mix high performance concretes such as UHPC

and SCC. Research, determined a shorter mixing

time for all types of concrete in case of intensive

mixers.

• The use of a stabilisation time to determine the

optimal mixing time and workability has proven

useful. The stabilisation time is mainly influenced

by the relative concentration of solids ///max and

the mixing speed.

• A higher mixing speed can be used to reduce the

mixing time. However, an excessive speed can

lead to overmixing. This is especially the case for

SCC, for which a sensitive increase in speed can

have a large influence on the workability.

• A delayed addition of the superplasticizer, leads to

an improved workability, especially when a low

water-to-cement ratio is used. A similar conclusion

can be made when a cement with a low C3A-

content and Blaine fineness is used.

• Vacuum mixing can lead to improved concrete

properties. Preliminary results however revealed a

lower influence of a reduced air pressure in a 75 l

intensive vacuum mixer in comparison with a 5 l

intensive vacuum mixer. Further research is

ongoing.

Acknowledgments The financial support of the Hercules

Foundation and of the Fund for Scientific Research Flanders is

greatly acknowledged.

References

1. Beitzel H (1982) Bedeutung der Mischzeit fur Konstruktion

und Einsatz von Betonmischern. BMT 29 heft 5:S.230–

S.234

2. Charonnat Y, Beitzel H (1997) RILEM TC 150 ECM:

efficiency of concrete mixers; report: efficiency of concrete

mixers towards qualification of mixers. Mater Struct (Suppl

196) 30:28–32

3. Chopin D, De Larrard F, Cazacliu B (2004) Why do HPC

and SCC require a longer mixing time? Cem Concr Res

34:2237–2243

4. Chopin D, Cazacliu B, De Larrard F et al (2007) Monitoring

of concrete homogenisation with the power consumption

curve. Mater Struct 40:897–907

5. Diawara H, Ghafoori N (2011) Influence of hauling time on

fresh properties of self-consolidating concrete. ACI Mater J

108:244–251

6. Dils et al (2011) Mixing procedure for self-compacting

cementitious materials (in Dutch). Unpublished work

7. Dils et al (2011) Influence of the mixing procedure on the

properties of traditional cementitious materials (in Dutch).

Unpublished work

8. Dils J, De Schutter G, Boel V (2012) Influence of vacuum

mixing on the mechanical properties of UHPC. In: Inter-

national symposium on ultra high performance concrete,

Kassel, 7–9 March 2012, pp 241–248

9. DIN EN 206-1 (2002) Produktionskontrolle, Beton-

Kalender 2002, Erganzungsband, Verlag Ernst &Shn,

Weinheim, S.233

10. Fernandez-Altable V, Casanova I (2006) Influence of mix-

ing sequence and superplasticiser dosage on the rheological

response of cement pastes at different temperatures. Cem

Concr Res 36:1222–1230

11. Ferraris CF (2001) Concrete mixing methods and concrete

mixers: state of the art. J Res Nat Inst Stand Technol

106:391–399

12. Flatt R, Houst YF (2001) A simplified view on chemical

effects perturbing the action of superplasticizers. Cem

Concr Res 31:1169–1176

Fig. 23 Concrete slump flow in dependence of applied pressure

[8]


13. Geiker MR, Ekstrand JP, Hansen R (2007) Effect of mixing

on properties of SCC. In: Fifth international RILEM sym-

posium on self-compacting concrete, vol 1, pp 231–238

14. Lowke D, Schiessl P (2005) Effect of mixing energy on

fresh properties of SCC. In: Proceedings of the 4th inter-

national RILEM symposium on self-compacting concrete,

Chicago, USA

15. Martinek R (1984) Doppelwellen – trogmischer in Chargen-

und kontinuierlicher Bauweise. BMT 31Heft 4 ? 5S:

147–154

16. Mazanec O, Schiessl P (2008) improvement of UHPC

properties through an optimized mixing procedure. In: 8th

International symposium on utilization of high-strength and

high-performance concrete, Tokyo, Japan, 27–29 October

2008, pp 307–313

17. Mazanec O, Lowke D, Schiessl P (2009) Mixing of high

performance concrete: effect of concrete composition and

mixing intensity on mixing time. Mater Struct 43(3):

357–365

18. Nold P (2006) Mischen von beton: was muss man beachten,

um betonegleichmassig gut aufzubereiten? Bayerische

bauakademie

19. Schachinger I, Schubert J, Mazanec O (2004) Effect of

mixing and placement methods on fresh and hardened ultra

high performance concrete (UHPC). In: Proceedings of the

international symposium on ultra high performance con-

crete, 13–15 September 2004, pp 575–586

20. Schiessl P, Mazanec O, Lowke K (2007) SCC and UHPC-

effect of mixing technology on fresh concrete properties. In:

Advances in construction materials part VI, pp 513–522

21. Schwartzentruber A, Catherine C (2000) La methode du

mortier de betonequivalent (MBE)-Un nouveloutild’aide a

la formulation des betons adjuvants. Mater Struct 33:

475–482

22. Takahashi K, Bier TA, Westphal T (2011) Effects of mixing

energy on technological properties and hydration kinetics of

grouting mortars. Cem Concr Res 41:1167–1176

23. Vickers TM Jr, Farrington SA, Bury JR, Brower LE (2005)

Influence of dispersant structure and mixing speed on con-

crete slump retention. Cem Concr Res 35:1882–1890

24. Williams DA, Saak WA, Jennings HM (1999) The influence

of mixing on the rheology of fresh cement paste. Cem Concr

Res 29:1491–1496

25. Yang M, Jennings HM (1995) Influences of mixing methods

on the microstructure and rheological behavior of cement

paste. Materials, Sciences and Engineering and Civil

Engineering, Northwestern University, Illinois

26. Yubakami A, Hashimoto C et al (2011) Development of bi-

axial forced mixing type mixer having high mixing effi-

ciency for high performance concrete with help of a visu-

alization technique. In: 9th International symposium on

high performance concrete

27. Zain MFM, Saifuddin M, Yusof KM (1999) A study on the

properties of freshly mixed high performance concrete.

Cem Concr Res 29:1427–1432


Documents

Influence of Mixing Procedure and Mixer Type on Fresh