| Abstract | A detailed study was conducted to investigate the properties of grouts containing supplementary cementitious materials and to optimize proportion of raw materials by using the Design-Expert 7.1.6 software. In this study, pozzolans namely fly ash and metakaolin have been selected as constituents to improve the quality of grouts. Fly ash was used to replace the cement in the amount of 20, 30, and 40%, whereas the metakaolin was used in the amount of 10, 15, and 20% by weight of cementitious materials respectively. The 0.17 of water to binder ratio (W/B) of the mixtures, a dosage of superplasticizer was used to maintain workability and fixed to 3.3% by weight of cement and used for all mixes. Fine sand was also fixed to 52% by weight of cement and used for all mixes. The flowability, bleeding and setting time of fleshly mixed grouts were determined. The compressive strength was determined for hardened grouts at various curing durations up to 91 days. For the optimization part, the objective was to optimize proportion of raw materials by using statistical mixture design with boundary restriction on the contents which was ordinary Portland cement, 60 to 90%, Fly ash, 10 to 40%, and metakaolin, 10 to 20%.
The results indicated that the used of fly ash as supplementary cementitious material by replacing ordinary Portland cement significantly improves the flowability of cement grout, but led to increase the bleeding in the final state, prolong setting time and reduce the compressive strength. The cement grout containing metakaolin was found to improve the overall performance of cement grout. Metakaolin was effective in eliminated bleeding, shortening setting time and enhancement the compressive, but led to increase the flow time. For grout containing the combination of fly ash and metakaolin, it can provide a good balance among flowability, bleeding, setting time and compressive strength. Finally, the Design expert software was a great tool to obtain the optimal proportions of SCMs grouts and to develop grouts, which showed good results with met all specify requirements. |