A Study on Mechanical Properties, Water Absorption and Microstructure of Cementitious Mortar containing Recycled Admixtures

Economic concerns and environmental issues have led to increased use of recycled materials in cementitious mortars. In fact, to mitigate the adverse effects of cement, it can be partially replaced with recycled materials. In this paper, cement was partially replaced with iron, rubber, glass and eggshell powders (IP, RP, GP and EP) by 7, 14, 21 and 28% and then, compressive and tensile strength, water absorption and microstructure of the specimens were assessed. The strength tests, as well as microstructure analysis, were conducted at the age of 28-day and the water absorption was tested at the ages of 7, 28, 56 and 90 days. Based on the results, use of all powders by 14%, enhances the compressive strength up to 14%. Moreover, it was found that up to replacement ratio of 28%, the tensile strength is greater than that of the control specimen although, in the case of 7% admixtures, maximum tensile strength is achieved. In addition, water absorption of the specimens containing GP and EP up to 35% replacement ratio, is less than that of the other specimens, which was well observed in the SEM analyses.