Development of low heat concrete using fly ash and pumicite | |
| Author | Anu-Thanit Srichool |
| Call Number | AIT Thesis no.ST-97-21 |
| Subject(s) | Aggregates (Building materials) Fly ash |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. ST-97-21 |
| Abstract | This research is aimed at developing a Low Heat Concrete (LHC) using high volume pozzolan replacement. Local pozzolan namely Rayong fly ash (FAR), Mae-Moh fly ash (FAM) and a pumicite (PM) were selected as the cement replacement material in this study. All pozzolans used were primarily tested for their chemical composition and physical properties. Experimental investigations were conducted to investigate the properties of the developed LHC, with different types and replacement percentages. The replacement percentages of each type of fly ash were 40%, 50% and 60% by weight of cementitious materials, respectively, while pumicite replacement was 50% by weight. Then a combination of fly ash and pumicite replacement each comprising 25 % by weight of the total cementitious materials was also tested. A total of 10 mix proportions of plain concrete without superplasticizer were prepared, mixed and cast. The water to binder content ratio (w/b) of all mix proportions were kept constant and equal to 0.55 throughout the experimental program. The test properties are thermal properties (quasi-adiabatic temperature rise), mechanical properties (compressive strength, flexural strength, and modulus of elasticity) and durability (drying shrinkage). These properties are considered to be affected mainly by the chemical composition of the pozzolans used. The properties of LHC mixtures were also compared with the properties of plain cement concrete mixture (CC). From the test results, it was found that the developed LHC using high volume pozzolan replacement could reduce the temperature rise of concrete effectively. From the test results among LHC mixtures (FAR, FAM, and PM), with the same amount of pozzolan replacement, PM mixture had the lowest temperature rise and the lowest compressive strength when compared with the other two mixtures. It was also found that FAR mixture had the highest temperature rise and the highest compressive strength, at any age of concrete. The strength of PM concrete was found to improve when PM was mixed with FAR or FAM. From the test data, higher fly ash replacement percentage leads to the lower temperature rise and lower compressive strength of LHC. In testing of flexural strength and modulus of elasticity of LHC, the results were found to be in a pattern similar to compressive strength. Drying shrinkage of LHC mixture with both types of fly ash replacement is lower than that of CC mixture, but LHC mixture with PM gave higher drying shrinkage than CC mixture. From the tested data of this study and the data obtained from the other researchers, with various mixture conditions of high volume fly ash concrete, models for predicting temperature rise and compressive strength of LHC with high volume fly ash were proposed. The models determine the effect of percentage of fly ash replacement and the total cementitious material by the parameter C (unit CaO content) which is considered mainly to affect the temperature rise and compressive strength of LHC. The effect of water-binder content ratio was considered as another parameter in the compressive strength model. Experimental results of high volume fly ash concrete were used to verify the proposed model. The proposed models were found to be effective in predicting peak temperature rise and 28-day compressive strength of high volume fly ash concrete. The proposed models were also verified by the tested results of the pumicite mixtures from this study. Finally, based on the compressive strength at 28 days, the maturity concept of concrete was found to be applicable for approximately predicting the time-dependent compressive strength of the developed LHC. |
| Year | 1997 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. ST-97-21 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Pichai Nimityongskul |
| Examination Committee(s) | Somnuk Tangtermsirilml;Niwa, Junichiro;Wijeyewickrema, Anil C. |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 1997 |