Modeling for expansion of expansive mortar under free and restrained situations | |
| Author | Suchart Pattanasuttinont |
| Call Number | AIT Thesis no.ST-99-4 |
| Subject(s) | Expansive concrete Mortar Expansive concrete Mortar |
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of Master of Engineering. |
| Publisher | Asian Institute of Technology |
| Abstract | Expansive concrete is a kind of concrete which hardens accompanied by expansion. The aim of using expansive agent is to produce shrinkage-compensate and self-stress concrete. The use of expansive concrete in RC structures result in a significant reduction in crack formation and width of cracks caused by drying shrinkage compared to the use of ordinary concrete. Expansion of expansive concrete must be dete1mined in order to use expansive concrete. Following the constant energy concept, expansion of expansive concrete can predict at variety degree of restraining when a standard test that have same mix proportion and curing condition is conducted. According to composite material model concept, a computational program was done to predict expansion of expansive mortar at va1y of mix proportions. Two factors that have significant effect to expansion are water-powder ratio and content of expansive agent. These two factors were expressed in the program in form of material properties such as elastic modulus, tensile strength and potential expansion strain. The composite material model can predict expansion according to material properties that are input of this model, which this material properties is indirectly expressed effect of water-powder ratio and content of expansive agent. The limitation of this model was non linear relationship between content of expansive agent which the most significant effect and alpha which represents volume fraction of expansive agent. Multi-component heat hydration model can predict degree of hydration of each component of blend cement depend on temperature and chemical composition of blend cement. As already known that material properties such as tensile strength or elastic modulus can expressed in form of degree of hydration. So coupling model between composite material model and heat hydration model in order to make more generalize form of input to predict expansion. A component for expansive agent was newly implemented to multi-model in this study to evaluate degrees of reaction not only of cement compounds but also expansive agent. Coupling model can express effect of water-powder ratio and content of expansive agent directly from mix proportion. In order to investigate performance and applicability of the coupling model , sensibility analysis was done. An experiment to measure expansion of many mix proportion was done. The result from experiment was used to verify with result from both composite model and the coupling model. In both cases the accuracy was in an acceptable level. |
| Year | 1999 |
| Type | Thesis |
| School | School of Engineering and Technology |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Construction Engineering and Infrastructure Management (CM) |
| Chairperson(s) | Kishi, Toshiharu;Kishi, Toshiharu; |
| Examination Committee(s) | Pennung Wamitchai;Manavazhi, Mohan Raj; |
| Scholarship Donor(s) | AIT Partial Scholarship; |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 1999 |