Experimental Investigation Of Properties Of Recycled Aggregate Concrete With Enset Fibers

Abstract

Concrete is the world’s most widely used construction material which has superior properties like excellent versatility, availability and economy compared to other structural materials. Construction and demolition waste constitutes a major portion of total solid waste production in the world, and for the present most of it is used in landfills. The most effective way to reduce the waste problem in construction is agreed in implementing reuse, recycling and reduced the use of a construction material in construction activities. Due to the environmental and economic concerns, the need for re-using recycled construction material becomes inevitable. This study was aimed to investigate the properties of recycled aggregate concrete with the addition of Enset fibers. To achieve this aim, an experimental investigation was carried out on fresh and mechanical properties of recycled aggregate concrete with Enset fibers. The fresh and mechanical properties of recycled aggregate concrete with different contents of Enset fibers were evaluated. Workability of fresh concrete was determined by slump test and compaction factor test methods. Mechanical properties of concrete like; compressive strength, flexural strength, splitting tensile strength and stress-strain relations were conducted and results were analyzed and compared with control groups. In all 84 concrete specimens were cast and tested for compressive strength, flexural strength and splitting tensile strength. Experimental results show that the addition of Enset fibers influenced the fresh and mechanical properties of recycled aggregate concrete. Reduction of 7.40% in fresh unit weight concrete was obtained when natural aggregate is replaced by 100% recycled coarse aggregates. The slump values of recycled aggregate concrete mixes with 0.5% and 1.0% Enset fibers were decreased by 20mm and 25mm respectively, compared with recycled aggregate concrete mixes without Enset fibers. Enhancement of 3.63% and 1.20% on compressive strength at 0.5% and 1.0% Enset fiber contents respectively, was achieved after 28 days. The recycled aggregate concrete produced with 0.5%, and 1.0% fiber contents showed 6.01% and 4.83% improvements respectively, in their tensile splitting strength. The flexural strength of recycled aggregate concrete specimens produced with 0.5% and 1.0% by volume of Enset fibers increased by 12.64% and 16.09% respectively. Beyond 1.5% fiber contents the modulus of rupture was reduced when contrasted to other fiber contents. Finally, this study concludes that the recycled aggregate concrete produced with 0.5% and 1.0% Enset fibers with 100% recycled coarse aggregate have a good mechanical performance. The maximum compressive strength value of 34.04MPa at 28 days was attained with a fiber content of 0.5% and the maximum modulus of rupture obtained was 7.07MPa at 28 days with a fiber content of 1.0%. Therefore, it is recommended to use recycled aggregate with Enset fiber contents up to 1.0% for normal concrete class of 25MPa