Resumen de Strength and microstructural behaviour of concrete incorporating laterite sand in binary blended cement
Rajapriya Raja, Ponmalar Vijayan
This paper explores the performance of concrete using laterite sand as a fine aggregate alternative by replacing manufactured sand (M-sand, produced from hard granite stones by crushing) at 25% intervals ranging from 0% to 100%. Preliminary tests were conducted to ascertain the properties of Msand and laterite sand that meet the recommended standards for natural aggregates. M30 grade concrete mixtures were produced, and the specimens were cured for 7 and 28 days. The slump test was carried out to assess the workability as per Indian Standards. Furthermore, the concrete specimens were prepared in the form of cubes, cylinders, and beams to assess the mechanical performance. Also, control and optimum mixtures were chosen to understand its morphological characteristics by conducting Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), X-Ray Diffraction (XRD) and Thermogravimetric Analysis (TGA). Results showed that higher laterite content led to less workable concrete, and 25% replacement of laterite sand improved by about 12%, 11% and 13% respectively compressive, split-tensile, and flexure strengths. Based on the SEM analysis, the optimum mixture showed a more compact microstructure. The EDS analysis confirmed the presence of various hydration products, while the XRD analysis indicated that the L25 samples had additional peaks of tobermorite and xonotlite. The results of TGA are also in agreement with the assertion.
