Due to the increased demands of adapting the sustainability concept in the construction industry, many researchers have developed and evaluated the composite materials made with agricultural by-products, such as straws, fruit-shells, and cobs, as construction materials. Because no research work has been reported regarding the incorporation of common reed fiber (CRF) into a concrete composite to produce the green and sustainable concrete, this research has focused on the evaluation of physical, mechanical, and thermal properties of mortar mixture containing CRF regarding density, porosity, compressive and flexural strengths, and thermal conductivity. In total, six mixtures with 0%, 2%, 4%, and 6% CRF; 0.5% steel fiber (SF); and the combination of 6% CRF and 0.5% SF were prepared. Based on the experimental outputs, a simple analysis of heat loss was also been performed. The test results presented that the incorporation of CRF into mortar mixture proportionally reduced its unit weight and significantly increased its absorption capacity and porosity. Although the use of only CRF in the mortar mixture did not improve both compressive and flexural strengths compared to the plain mixture, the combined use of CRF and SF to increase both compressive and flexural strengths generated a synergetic effect to increase both strengths. The addition of CRF to the mixture has the benefit of producing a significant decrease in heat loss for a typical building in Astana due to the lower thermal conductivity and higher porosity to density ratio.

Blast furnace slag (SL) is an amorphous calcium aluminosilicate material that exhibits both pozzolanic and latent hydraulic activities. It has been successfully used to reduce the heat of hydration in mass concrete. However, SL currently available in the market generally experiences pre-treatment to increase its reactivity to be closer to that of portland cement. Therefore, using such pre-treated SL may not be applicable for reducing the heat of hydration in mass concrete. In this work, the adiabatic and semi-adiabatic temperature rise of concretes with 20% and 40% SL (mass replacement of cement) containing calcium sulfate were investigated. Isothermal calorimetry and thermal analysis (TGA) were used to study the hydration kinetics of cement paste at 23 and 50 °C. Results were compared with those with control cement and 20% replacements of silica fume, fly ash, and metakaolin. Results obtained from adiabatic calorimetry and isothermal calorimetry testing showed that the concrete with SL had somewhat higher maximum temperature rise and heat release compared to other materials, regardless of SL replacement levels. However, there was a delay in time to reach maximum temperature with increasing SL replacement level. At 50 °C, a significant acceleration was observed for SL, which is more likely related to the pozzolanic reaction than the hydraulic reaction. Semi-adiabatic calorimetry did not show a greater temperature rise for the SL compared to other materials; the differences in results between semi-adiabatic and adiabatic calorimetry are important and should be noted. Based on these results, it is concluded that the use of blast furnace slag should be carefully considered if used for mass concrete applications.