Analysis of the Modifying Effect of Kortta Fibers and Micro-silica on the Properties of Structural Light weight Concrete

The weight loss of concrete as a structural material and consequently reduction in its cost has always been considered. Light weight concrete made of industrial Leca is propounded as useful alternatives for reducing concrete specific weight due to its low specific weight and acceptable resistance property. So demand for using it is increasing in recent years. In order to enhance the defects and stability of lightweight concrete, in this study, polymer Kortta fibers with percentage of ۰, ۰.۵, ۱, ۱.۵, and ۲ % and micro-silica with percentage of ۰ and ۱۵% by cement weight were incorporated in both single and combined forms. Then after ۲۸-days of curing in water and drying, compressive, tensile, flexural and short water absorption tests were conducted on them. Finally, ۱.۵% fiber and ۱۵ % micro-silica was chosen as the optimum percentages of additives. The results show that in this percentage of cement supplements, compressive, tensile and flexural strength were increased by ۵۳, ۹۷, and ۷۴%, respectively, compared with un-modified specimen, also there was ۲۹% decrease in short water absorption in comparison with un-modified specimen.