Study of Lightweight Mortar by Replacing Cement and Aggregates with Admixtures

The research focuses on the study of admixtures used for producing lightweight mortar by replacing cement and fine aggregates. Mortar is a composition of water, fine aggregate and binding material. The concept of sustainable development and reduction in environmental degradation has been the talk of the hour for numerous years, and its application in the field of civil engineering is inevitable. Since cement production has multiple adverse effects on the environment and also the excessive instream sand mining causes the degradation of rivers, the objective of this research is to replace cement with metakaolin, silica fumes, ground granulated blast furnace slag (GGBS), lime and nano-silica materials. Plenty of aforementioned admixtures are basically waste products. Solid glass beads and cenosphere are used to replace sand entirely. Fifteen mix designs of different composition have been tested and analysed. Variety of tests including ultrasonic pulse velocity test, split tensile strength test and compressive strength test was performed to determine structural characteristics of the concrete mix. The optimum percentage of substitution is as follows: cement (35%), metakaolin (28%), silica fumes (12%), slag (15%), lime (10%) and nano-silica (0%). The selected mortar samples were characterized by the means of destructive and non-destructive tests, and the efficient mortar mix was analysed using scanning electronic microscope (SEM analysis).