Reducing variations in the test results of self-consolidating lightweight concrete by incorporating pozzolanic materials

Abstract

Portland limestone cement (PLC) has been considered as a suitable alternative for portland cement in self-consolidating lightweight concrete (SCLWC) mixtures. However, certain inconsistencies were reported in terms of strength development and durability properties of the PLC concrete. In addition, fresh SCLWC mixtures are more likely to encounter test results variation than ordinary concrete mixtures. This paper experimentally investigates the fresh and hardened performance of SCLWC incorporating ternary blended cements containing PLC and silica fume (SF), fly ash (FA), natural zeolite (ZE) or metakaolin (MK). The fresh tests were repeated once for each 100-L concrete batch and coefficient of variation as a measure of dispersion of a frequency distribution used to determine the variation of fresh test results of the mixtures. The results show that the pozzolanic materials mixtures have greater but less variable results of flowability compared to the PLC mixture. The coefficient of variation in results of slump flow test is varied 0.8–2.9%. It was also observed that there is a reduction in variation of the V-funnel results as the mean value increased. The obtained coefficient of variation was as low as 7% for zeolite ternary mixtures and the highest variation belonged to the binary mixture by 19.2%. The result of rapid chloride migration test (RCMT) and electrical resistance test indicated that there is a strong correlation between these two variables. Comparing the results to other studies, we recognized that the correlation seems to be unique for each case study.