Utilization of boron waste borogypsum in mortar

Abstract

In this study, mortars containing borogypsum (MCB) were investigated to understand the effect of borogypsum on mortars and if borogypsum could be used as a mineral admixture in the mortars. Borogypsum were replaced with cement at 0%, 3%, 5%, 10% and 15% by mass. Flow table, flexural and compressive strength, abrasion, carbonation, sorptivity and shrinkage tests were conducted to the mortar samples including borogypsum. According to the test results, 3% and 5% replacement of borogypsum with cement resulted in increases in compressive and tensile strengths of the mortars and 10% borogypsum containing reached a high compressive strength but at later ages, these replacements resulted in a decrease in abrasion and deepness of being carbonated of the mortars. It was seen that the increased borogypsum decreased the consistency of the mortars. It was also observed that addition of borogypsum decreased shrinkage of the mortars which were studied up to the 28th day. Thus, borogypsum is recommended to be used as an admixture 5-10% of cement by mass in the mortar. The variance analysis of the hardened properties of mortar is also determined by using Response Surface Methodology (RSM) regression models. According to ANOVA results, it was determined that the flexural and compressive strength was directly affected by the borogypsum replacement ratio. It was determined from the ANOVA analysis, in which the double effect of both borogypsum and cement amount is higher than individual effects.