Modelling sulphate resistance of mortar containing eco-processed pozzolan

• Main Author: Hanni Morisha Moktar
• Format: Academic Exercise
• Language: English; English
• Published: 2022
• Subjects: TP875-888 Cement industries
• Online Access: https://eprints.ums.edu.my/id/eprint/35215/1/24%20PAGES.pdf; https://eprints.ums.edu.my/id/eprint/35215/2/FULLTEXT.pdf; https://eprints.ums.edu.my/id/eprint/35215/

Sulphate attack on concrete is the most common issue occur in the construction industry. The effect of the sulphate on the concrete for a short term was evaluated in terms of the expansion of mortar. However, the laboratory test of mortar expansion owing to sulphate is taking longer duration to complete. Therefore, the purpose of this research is to identify the optimum percentage of Eco-Processed Pozzolan (EPP) in mitigating the sulphate attack in concrete and to determine the expansion of EPP mortar when exposed to long-term sulphate exposure using Response Surface Methodology (RSM) from Design Expert 13 software. The models in RSM are developed according to the experimental design, where the RSM describe the relationship between the parameters which are testing duration, size of EPP, percentage of EPP and expansion of mortar. From the research, it can be identified that the addition of EPP as a partial replacement in concrete reduce the expansion of mortar compared to the control mix when exposed to sulphate environment for 56 days. In addition, the fineness of EPP influence the expansion mortar as partial replacement of ground EPP in mortar lower the expansion compare to unground EPP. Based on the optimization using RSM, the optimum percentage of EPP obtained is 40%. In addition, a cubic equation is developed from the Analysis of variance (ANOVA) where this equation is used to predict a long-term sulphate exposure in term of expansion of mortar for 91 days, 105 days, 120 days and 180 days. The expansion-predicted data obtained increased until 56 days and shrinkage of mortar occur up until 180 days except for 40% of ground EPP where the mortar expand on 105 days of testing and shrink after reach 120 days of testing. This might due to the error occur during the simulation process. This is due to the equations generate from the RSM was limit for only 56 days. Therefore, the prediction for a long-term expansion after 56 days was no relevant in this study. However, this research shows that using EPP as supplementary replacement in cement can give positive impact to the durability and strength of mortar. It also improves the sulphate resistance of mortar when exposed to sulphate environment. Hence, the concern on sulphate attack that commonly occur in construction industry can be reduce.