Impact on mechanical properties of cement sand mortar containing waste granite powder

•Fine aggregate in cement mortar has been replaced partially by granite waste powder.•Mechanical properties of cement mortar containing waste granite powder have been studied.•Results of study have been supported by micro analysis. Solid waste management is a global challenge. Slurry generated from granite processing industries is one of the major sources of total solid waste production. This paper reports the feasibility of utilizing waste generated from cutting and finishing of granite blocks as a replacement of fine aggregate in mortar mixes. With this in mind, fine aggregate in cement mortar mixes was replaced by waste granite powder in the range of 30–40% by volume. Workability, compressive strength, tensile bond strength, adhesive strength, water absorption, drying shrinkage and ultra-sonic pulse velocity, dynamic modulus of elasticity of all the mortar mixes were studied. It was observed that water requirement reduces by 7 and 3% at 30 and 40% by volume replacement respectively in blended mortars. This lesser water content for the same amount of workability has helped in improving other mechanical properties of such mortars. Compressive strength, tensile bond strength and adhesive strength were increased by 4%, 23% and 23% respectively as compared to those of control mortar in 1:4 mix proportion. Drying shrinkage for blended mortars was comparable to that of the control one. Substitution by waste granite powder also increased the volume of hydrated cement which was confirmed by Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) techniques. Hence it is concluded that such blended mortars perform better than conventional ones and therefore can be safely used for masonry and plaster work.