Mechanical properties of eco-friendly high strength lightweight concrete using bottom ash as replacements of cement and aggregates

This article aims to assess mechanical properties of eco-friendly high strength lightweight concrete using bottom ash as replacements of cement and aggregates. Bottom ash received directly from a power plant was classified into 3 parts by sieving. The first one was the bottom ash which was sieved through a sieve No. 4 and ground to have high fineness. Then, it was used to replace hydraulic cement at a rate of 50% by weight. The second part was the bottom ash passing a sieve No. 4 and was used to replace fine aggregate at a rate of 100% by volume of fine aggregate. The third part was the bottom ash passing a 1⁄2 inch sieve and retaining on a sieve No. 4 and was used to replace coarse aggregate at the rates of 25, 50, 75, and 100% by volume of coarse aggregate. The total binder content of all concretes was 600 kg/m3 and a water to binder ratio was set as a constant of 0.25. Slump of fresh concrete was controlled between 15 and 20 cm by using superplasticizer. The results were found that the bottom ash used as cement and aggregate replacements at high volume could produce eco-friendly high strength lightweight concrete which was 40 MPa at 28 days. The use of bottom ash as aggregates replacement gave the voids content of concrete of 25% and the thermal conductivity of 0.45 watts per meter-kelvin (W/m °K). Additionally, the density and compressive strength of concrete were reduced with the increase of the bottom ash content.