The effect of physical properties of pond ash as a partial replacement of sand in the mortar mix

Abstract

The major focus of the present study is the use of pond ash to replace fine river sand in the production of plaster. In this study, the physical, mechanical, and microstructure characteristics of mortar are investigated for different replacement levels of sand with pond ash. The results show that the dry density of pond ash mixes is reduced by increasing the replacement level, which is due to the higher water absorption and pond ash’s porousness. It is worth mentioning that at a replacement rate of 20%, compressive and flexural strengths are higher than those of control specimens. On the other hand, drying shrinkage is 31% lower than the control, but the achieved strength is more than the required strength as per the Indian code. Scanning electron microscopy with energy dispersive x-ray spectroscopy shows that a rise in silicon content (12%) for samples having a 20% replacement of pond ash has a high C–S–H gel density, thus exhibiting higher compressive and flexural strengths. X-ray diffraction results show that the lower strength of 40% pond ash replacement is due to the presence of sodium sulfate. Hence, the results indicate that fine pond ash can be partially replaced with fine river sand for internal plaster and to produce mortar and blocks.