Module (Course Syllabus) Catalogue 2019-2020 (concrete).pdf · 2020-01-13 · Module type Prerequisite Core Assist. Weekly hours 5 Weekly hours (Theory) (2) hr Class ( )hr ... Slump

Directorate of Quality Assurance and Accreditation ینخشبهتی دڵنیایی جۆری و متمانهرایهبهڕێوهبه

Module (Course Syllabus) Catalogue

2019-2020

College/ Institute Erbil Technical Engineering College

Department Highway Engineering Department

Module Name Concrete Technology

Module Code HE204 Semester Yearly system

Credits

Module type Prerequisite Core Assist.

Weekly hours 5

Weekly hours (Theory) (2)hr Class ( )hr Workload

Weekly hours (Practical) (3)hr Class ( )hr Workload

Lecturer (Theory) Hana Sherzad Aziz

E-Mail & Mobile NO. [email protected] , 07504918619

Lecturer (Practical) Hana Sherzad Aziz

E-Mail & Mobile NO. [email protected] , 07504918619

X

mailto:[email protected]

mailto:[email protected]


Course Book

Course Description

Approach to study of concrete The order of our lectures is as follow: Concrete ingredients: cement, aggregate, and mixing water. Then concrete in its fresh state following by the strength of concrete because it is one of the most important properties of concrete and it is always prominent in the specifications. Having established how we make concrete and what we fundamentally require, we turn to some techniques: mixing and handling, use of admixtures to modify the properties at this stage, and methods of dealing with temperature problems. In the following lectures, we study other properties of concrete and finally mix design. Concrete as a structural material These days, there are two commonly used structural materials: concrete and steel. They sometimes complement one another, and sometimes compete with one another, so that many structures of a similar type and function can be built in either of these materials. In actual practice, the man on the job needs to know more about concrete than about steel. Why?

Steel is manufactured under carefully controlled conditions, always in a highly developed plant; the properties of every type of steel are determined in a laboratory and described in a manufacturer's certificate. Thus, the designer of a steel structure needs only specify the steel matching a relevant standard, and the constructor needs only ensure that correct steel is used.

On a concrete building site, the situation is totally different. It is true that the quality of cement is guaranteed by the manufacturer in a manner similar to that of steel. However, cement is not the building material: concrete is.

It is possible to obtain concrete of specified quality from a ready-mix supplier but even in this case, it is only the raw material that is bought. Transporting, placing and, above all, compacting greatly influence the final product.

Moreover, unlike the case of steel, the choice of mixes is virtually infinite and therefore the selection cannot be made without a well knowledge of the properties and behavior of concrete.

It is thus the competence of the designer that determines the potential qualities of concrete, and the competence of the contractor and the supplier that controls the actual quality of concrete in the finished structure.


Course objectives

Understanding concrete and its properties Concrete behavior under load, temperature, and humidity

changes Identifying materials used in concrete and their properties Concrete types Concrete mix design Significant tests of fresh and hardened concrete Significant tests of cement Significant tests of aggregate Concrete properties in its fresh state Concrete properties in its hardened state

Student's obligation

All students are required to fulfil the following requirements: Attendance Participation in Lab tests Report for each test Participation in theory part exams Participation in practical part exams Site visits (if applicable)

Required Learning Materials

Data show and power-point Lecture hand-outs Test hand-outs Videos of tests White board

Assessment scheme

Mid-year theoretical part exam 25Marks Mid-year practical part exam 10Marks Tests + reports 10Marks Quiz + Attendance 5Marks Final exam theoretical part 40Marks Final exam practical part 10Marks Overall 100Marks

Specific learning outcome:

Students will be able to: Be familiar with necessary items available at construction sites Work at construction and material laboratories Recognize common problems during transporting, handling and

placing of concrete Check concrete properties during its fresh and hardened state Deal with fresh concrete problems Strengthen themselves for the upcoming subjects in 3rd and 4th

year

Course References:

Concrete technology by A.M. Neville & J.J. Brooks Advanced concrete technology by ZONGJIN LI Advanced concrete technology by John Newman


Course topics (Theory) Week Learning Outcome

Introduction to concrete

1

Advantages and disadvantages of concrete discussed Concrete classifications presented with their applications

Introduction to concrete 2

Factors that affect on concrete properties are reviewed

Cement

3

Cement described with the primary sources of manufacturing of cement Cement manufacturing illustrated with photos and videos The chemistry of cement explained with the main oxides and compounds

Cement 4

Different types of cement introduced with their applications Some tests regarding cement explained

Aggregate 5

The nature and advantages of aggregate indicated Classifications of aggregate discussed

Aggregate 6

Some properties of aggregate showed The quality of aggregate and effect of impurities on aggregate presented

Mixing Water

7

The effects, functions and types of water in cement paste illustrated The effects of impurities and quality of mixing and curing water showed

Admixture 8

Admixture defined with its classifications Chemical admixtures explained with their advantages and applications

Admixture 9

Mineral admixtures explained with their advantage and applications

Fresh concrete

10

Fresh concrete defined with the most important requirements Some factors affecting on fresh concrete discussed

Fresh concrete 11

Some properties of fresh concrete explained with the effects

Hardened concrete

12

Hardened concrete and related terms defined Different types of concrete strength indicated with their failure modes and related tests A method to assess tensile strength of concrete provided

Hardened concrete 13

Factors that affect on hardened concrete introduced Concrete durability problems presented with


details Various way to control durability problems provided

Mixing, transporting, placing, compacting and finishing concrete

14

Different types of mixers introduced with their applications Mixing time and uniformity explained Ready-mix concrete presented with methods of transporting it

Mixing, transporting, placing, compacting and finishing concrete

15

Various ways of controlling segregation provided during placing concrete Some specialized techniques of placing concrete showed Various ways to compact concrete provided

Concreting in cold and hot weather

16

Various methods provided to deal with concreting in hot weather Various methods provided to deal with concreting in cold weather Some methods of curing introduced

Mix design

17

Factors that affect on mix design illustrated American method to design a concrete mix presented Amounts of concrete ingredients calculated using American method

Mix design

18

British method to design a concrete mix presented Amounts of concrete ingredients calculated using British method

Practical Topics Week Learning Outcome

Slump test 1 A method and test to measure and evaluate fresh concrete workability presented Factors affecting on slump test results illustrated

Flow table test 2 A method and test to measure and evaluate fresh concrete workability (high) presented Factors affecting on flow table test results illustrated

Compacting factor 3 A method and test to measure and evaluate fresh concrete workability presented Factors affecting on compacting factor test results illustrated

Vibrating table test 4 A method and test to measure and evaluate fresh concrete workability (low) presented Factors affecting on vibrating table test results illustrated


Compressive strength of concrete 5 A method and test to measure compressive strength of concrete provided Mechanism of failure under compression stress presented

Splitting strength of concrete 6 A method and test to measure tensile strength of concrete provided Mechanism of failure under tension stress presented

Flexural strength of concrete 7 A method and test to measure flexural strength of concrete provided Mechanism of failure under flexure stress presented Flexural strength calculated using centre point loading

Ultrasonic pulse velocity 8 A non-destructive test to evaluate compressive strength of concrete discussed A relationship between UPV and compressive strength of concrete defined

Rebound test 9 A non-destructive test to evaluate compressive strength of concrete discussed A relationship between Rebound and compressive strength of concrete defined

Specific gravity of cement 10 Specific gravity of cement determined Factors affecting on the test results explained

Compressive strength of cement 11 Compressive strength of cement determined Factors affecting on the test results explained

Standard consistency of cement 12 Standard consistency of cement determined The importance of standard consistency showed Factors affecting on the test results explained

Setting time of cement 13 Initial and final setting time of cement determined Factors affecting on the test results explained A relationship between initial and final setting time provided

Soundness of cement 14 Soundness of cement determined Factors affecting on the test results explained Unsound cement defined its causes

Specific gravity of aggregate 15 Specific gravity of aggregate determined The importance of specific gravity of aggregate introduced Factors affecting on the test results explained

Bulk density of aggregate 16 Loose and compacted bulk density of aggregate determined Effects of bulk density on concrete discussed


Sieve analysis of aggregate 17 Grading of aggregate determined Sieve analysis test results illustrated on a log-paper figure

Questions Example Design A question paper model and its typical answer are attached in the following:

Q1): Answer only six of the following questions (30Marks)

1. What are the consequences of careful curing and careless curing? 2. What are the functions of water in concrete? 3. How does particle size of coarse aggregate affect on workability? 4. How does the aggregate/cement ratio influences workability? 5. What are the consequences of bleeding? How to deal with it? 6. What are the effective ways to prevent concrete from plastic shrinkage? 7. What factors affect on tensile/compressive strength ratio of concrete?

Q2): Using a figure or sketch, answer only three of the following questions (15Marks)

A. Formation and hydration of Portland cement. B. Temperature rise in different types of Portland cement. C. Aggregate grading D. Shapes of aggregate

Q3): Answer only three of the followings (15Marks)

i. Applications (uses) of retarders ii. Applications (uses) of low-heat Portland cement

iii. Advantages of using air-entraining agent? iv. Drawbacks/disadvantages of accelerators, retarders and superplasticizers?

Q4): Classify the followings (10Marks)

a. Aggregate in accordance with size and source, and explain them briefly b. Causes of concrete deterioration, and what they include

Q5): State the reasons of only three of the followings (15Marks)

1. Why is concrete frequently used to build up protective layers for steel structures? 2. Why is gypsum added to cement during cement manufacturing? 3. What moisture condition of aggregate should be used in designing a concrete mix? Why? 4. Why do we use expansive cement?

Q6): A mix is required for a concrete foundation that will undergo 120-year exposure to carbonation

under the moderate humidity conditions. The mean 28-day compressive strength is 42 MPa with (4 second) Vebe. The foundation section and reinforcement dictate a nominal cover of 50 mm, using a maximum size of aggregate of 20 mm. The available coarse aggregate is uncrushed, and both the fine and coarse aggregates conform to the grading of BS 882: 1992, the fine aggregate corresponding to a grade, of which 40 per cent passes a 600µm sieve. The aggregates have a bulk specific gravity of 2.6. Design the concrete mix using the British method. (Note that 20 per cent of the cementitious material by mass is specified as fly ash)


Concrete Technology

Typical Answers and Solutions

Q1)

1

Careful curing:

Good microstructure

Proper strength

Good volume stability.

Careless curing:

Defects in the microstructure

Insufficient strength

Unstable dimensions.

2

It reacts with the cement powder, thus producing hydration products

It acts as a lubricant, contributing to the workability of the fresh mixture

It secures the necessary space in the paste for the development of hydration products.

3

The particle size of coarse aggregates influences the paste requirement for coating through the surface

area. The larger aggregates have smaller surface area than smaller aggregates with the same volume.

Subsequently, the amount of the paste available for lubrication is increased for concrete with large

aggregates, and consistency is improved.

4

A higher aggregate/cement ratio implies more aggregates and less cement paste. Thus, the concrete

consistency decreases with aggregate/cement ratio increase due to less cement paste being available

for lubrication.

5

Due to bleeding, an interface between aggregates and cement paste is formed, and the top of every lift

may become too wet.

Finishing problem can be avoided by delaying the finishing operations until the bleeding water has

evaporated.

6

Sheltering concrete surface from the wind and sunshine during construction

Covering the concrete surface immediately after finishing.

Minimum periods of curing.

7

Curing age

Water/cement ratio

Type of aggregate

Admixtures


Q2)


Q3)

1

Concreting in hot weather

Preventing the formation of cold joints between successive lifts.

Delay in hardening, which is useful to obtain an architectural surface finish.

Controlling setting time of large structural units to keep concrete workable throughout the

entire placing period

Long transportation time required from concrete plants to construction sites.

2

Large gravity dams

3

The workability of concrete can be improved so the water amount can be reduced.

The ductility of concrete can be improved.

The permeability of concrete can be improved due to the effect of air-entraining agent in

enclosing the air bubbles.

The impact resistance of concrete can be improved.

Most importantly, the durability, especially the ability to resist freezing and thawing of concrete,

can be significantly improved by adding an air-entraining agent.

4

One of the disadvantages is that in some cases calcium chloride has been found to cause

corrosion of reinforcing steel.

Retarders tend to increase the plastic shrinkage because the plastic stage is extended, but

drying shrinkage is unaffected.

The only disadvantage of Superplasticizers is their relatively high cost.


Q4)

1

In accordance with size:

Coarse aggregate (gravel): Aggregates mainly retained on a No. 4 (4.75mm) sieve are classified as

coarse aggregate.

Fine aggregate (sand): Aggregates passing through a No. 4 (4.75 mm) sieve and mainly retained on a

No. 200 (75 µm) sieve are classified as fine aggregate.

In accordance with source:

Natural aggregates: This kind of aggregate such as sand and gravel is taken from natural deposits

without changing the nature during production.

Manufactured aggregates: These kinds of aggregate are man-made materials, resulting from products

or by-products of industry. Some examples are blast furnace slag and lightweight aggregate.

2

A. Physical causes:

1. Surface wear caused by abrasion, erosion, and cavitation.

2. The effects of high temperature

3. The differences in thermal expansion of the aggregate and cement paste.

B. Chemical causes:

The most common chemical causes affecting concrete durability are

1. Chemical decomposition of the cement paste by reacting with water

2. Reaction with carbon dioxide

3. Reaction leading to expansion (such as sulfate expansion, alkali–aggregate expansion, and steel

corrosion).

C. Mechanical causes:

They include impact and overloading.

Q5)

1

Concrete can withstand high temperatures much better than wood and steel. Even in a fire, a concrete

structure can withstand heat for 2–6 hours, leaving sufficient time for people to be rescued. This is why

concrete is frequently used to build up protective layers for steel structures.

2

Gypsum is added (in order to prevent flash setting of the cement)

3

It will neither absorb water nor give out water during the mixing process. Hence, it is a balanced

condition and is used as the standard index for concrete mix design.

4

For many purposes, it would be recommended to use a cement which does not change its volume due

to drying shrinkage or even expands on hardening.


Q7)

From Table 19.2, the compressive strength of a mix with ordinary Portland (Type I) cement and a

water/cement ratio of 0.50 is 42 MPa. However, by referring to Table 14.4, for the nominal cover of 50

mm and carbonation-moderate humidity exposure conditions, the maximum free water/cement ratio

permitted is 0.55. Therefore, this lower w/c (0.5) ratio will be used.

From Table 19.5, with a Vebe of 4 second, the free water content required for uncrushed coarse

aggregate with a maximum size of 20 mm is 180kg/m³ of concrete, but this requires to be reduced by

10kg/m³ according to Table 19.6. This equation give the cement content as:

𝐶 =(100 − 𝑃)𝑊

(100 − 0.7𝑃) (𝑤

𝐶 + 0.3𝐹)

𝐶 =(100 − 20)(170)

(100 − 0.7 ∗ 20)(0.5)= 316𝑘𝑔/𝑚3

In addition, the fly ash content:

𝐹 =𝑃𝐶

100 − 𝑃

𝐹 =20 ∗ 316

100 − 20= 79𝑘𝑔/𝑚3

Hence, the cementitious material content is 316 + 79 = 395kg/m³ and the free water/cementitious

material ratio is 170/395 = 0.43. Both the cementitious material content and water/cementitious

material ratio satisfy the specified values of Table 14.4.

From Fig. 19.3, for aggregate with a bulk specific gravity of 2.6, and a free water content of 170kg/m³,

the wet density (unit weight) of concrete is 2400kg/m³, Hence, the total aggregate content is 2400 -

(170 + 395) = 1835kg/m³ of concrete.

From Fig. 19.4, for a free water/cement ratio of 0.43, a Vebe of 4 second, 40 per cent of fine aggregate

passes 600µm, and maximum size of aggregate of 20mm and specified fineness, the fine aggregate

content is 38 per cent of the total aggregate content. Hence, the fine aggregate content is 0.38 x 1835 =

622kg/m³ of concrete.

The coarse aggregate content is 1835 – 697 = 1138kg/m³ of concrete.

The estimated quantities in kg/m³ are as follows:

Cementitious material: 395

Fine aggregate: 697


Coarse aggregate: 1138

Added water: 170

Total: 2400

Extra notes:

External Evaluator As an Assistant lecturer at Highway Department, I have reviewed the course-book of the subject of Concrete Technology for 2nd stage, Department of Highway Engineering, Erbil Technical Engineering College/ Erbil Polytechnic University. I confirm that the course-book has well designed to achieve the aim and objectives of the subject. Furthermore, it almost covers all the required syllabus and contents of the course and describes satisfactorily the aspects related to the course.

Ali Jamal Nouri Assistant Lecturer/Highway Engineering Department

Documents

Module (Course Syllabus) Catalogue 2019-2020 (concrete).pdf · 2020-01-13 · Module type Prerequisite Core Assist. Weekly hours 5 Weekly hours (Theory) (2) hr Class ( )hr ... Slump