Compressive strength and microstructure analysis of a lightweight sand concrete in sodium sulfate environment

This article aims to study the compressive strength and the microstructure analysis of lightweight sand concrete, to know sand concrete lightened by wood shavings and barley straws, in sodium sulfate solution. The methodology is to make a comparative study of the compressive strength between both immersions, the first in water saturated with lime as a reference immersion and the second in sodium sulfate solution as a sulfate attack immersion, for a period of 18 months immersion. The microstructure analysis has been made between the lightweight sand concrete, before immersion compared to after 18 months immersed in a sodium sulfate solution. The results show that the lightweight sand concrete is considered to be a sustainable eco-material in the sodium sulfate environment. The advantage of the results is in favor of the weight changes and the compressive strength at 18 months immersed in a sodium sulfate solution, which increases by 40% compared to that before immersion, and the compressive strength increases of 58% compared to reference immersion (water saturated with lime). Furthermore, the results of microstructure analysis are very interesting, through a cross analysis, which was carried out by combining scanning electron microscopy, Fourier Transform-Infrared Spectroscopy and X-ray diffraction.