Hydration heat modeling of concrete using fly ash | |
| Author | Sarker, Prabir Kumar |
| Call Number | AIT Thesis no. ST-98-26 |
| Subject(s) | Heat of hydration Concrete--Thermal properties Fly ash |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering |
| Publisher | Asian Institute of Technology |
| Abstract | The study is aimed to incorporate some new functions regarding the thermal coefficients of concrete and hydration heat generated by fly ashes into the existing hydration heat model of concrete so that it can be used in a more generalized way and in a wider range to predict the temperature rise in concrete structures. COMH3 is a computer program in which the multi component hydration heat model is implemented. The model is based on the hydration heat characteristics of the mineral compositions of cement and those of the pozzolans used to replace cement partially. Three models are proposed here to determine the thermal conductivity and specific heat of hardening concrete and the material parameters of fly ashes. The model of thermal conductivity is based on the volumetric ratio of the ingredients of concrete and the hydrated product and their respective thermal conductivity values. In a similar way, the specific heat model computes the specific heat of concrete using the weight fractions of the ingredients and hydrated product together with their individual specific heat values. In the fly ash model, the reference heat rate and thermal activity of different types of fly ashes are expressed as function of their chemical compositions. The consumption ratio of Ca(OH)2 by the fly ash to produce C-S-H is expressed as a function of (CaO/SiO2) ratio of the fly ash and the percentage replacement of cement. So the model can be used to predict the temperature rise in concrete using cement replacement by any type of fly ash and by any percentage. The proposed models are verified by comparing the temperature rise values obtained from experiments with those predicted using COMH3. Results of a total number of twenty three experimental cases with different types of cement and cement replaced by different types of fly ashes in different percentages are used for the verification. Quasi-adiabatic temperature rise at center and surface of the test specimens were measured by thermocouples. Temperature data of one practical structures obtained from CP AC (The Concrete Product And Aggregate Co., Ltd., Bangkok) are also used for the verification of the model. Almost all the cases show good agreement of the test results with the analytical values. |
| Year | 1998 |
| Type | Thesis |
| School | School of Civil Engineering |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Structural Engineering (STE) /Former Name = Structural Engineering and Construction (ST) |
| Chairperson(s) | Kishi, Toshiharu;Somnuk Tangtermsirikul; |
| Examination Committee(s) | Pichai Nimityongskul; |
| Scholarship Donor(s) | Government of Japan; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1998 |