Reuse of waste ferrochrome slag in the production of mortar with improved thermal and mechanical performance

This study focuses on the reuse of waste ferrochrome (FeCr) slag as a partial replacement for sand in the production of cement mortar with improved thermal and mechanical properties. Sand was replaced by FeCr slag in different percentages ranging from 0 up to 20% (by weight). The flowability test was performed to evaluate the mortar's behavior in a fresh state. Tests for the compressive strength, flexural strength, drying shrinkage, thermal conductivity, and specific heat of the blended mortars have been conducted according to ASTM standards at 3, 7, and 28 days of curing. X-ray diffraction (XRD) was utilized to examine the phase composition. The scanning electron microscope (SEM) was used for inspecting the microstructure changes of the hardened samples. The results revealed considerable improvements in the compressive and flexural strengths; improvement ratios of about 33 and 39% were attained respectively at 20% FeCr slag replacement after 28 days of curing. The drying shrinkage generally decreased with increasing replacement of sand by FeCr slag. FeCr slag acts to increase both the thermal conductivity and specific heat effectively. FeCr slag caused remarkable modifications in the microstructure of the blended mortars.