*Article* **Effect of Recycled Coarse Aggregate and Bagasse Ash on Two-Stage Concrete**

**Muhammad Faisal Javed 1,\*, Afaq Ahmad Durrani <sup>2</sup> , Sardar Kashif Ur Rehman <sup>1</sup> , Fahid Aslam <sup>3</sup> , Hisham Alabduljabbar <sup>3</sup> and Amir Mosavi 4,5,6,7,\***


**Abstract:** Numerous research studies have been conducted to improve the weak properties of recycled aggregate as a construction material over the last few decades. In two-stage concrete (TSC), coarse aggregates are placed in formwork, and then grout is injected with high pressure to fill up the voids between the coarse aggregates. In this experimental research, TSC was made with 100% recycled coarse aggregate (RCA). Ten percent and twenty percent bagasse ash was used as a fractional substitution of cement along with the RCA. Conventional concrete with 100% natural coarse aggregate (NCA) and 100% RCA was made to determine compressive strength only. Compressive strength reduction in the TSC was 14.36% when 100% RCA was used. Tensile strength in the TSC decreased when 100% RCA was used. The increase in compressive strength was 8.47% when 20% bagasse ash was used compared to the TSC mix that had 100% RCA. The compressive strength of the TSC at 250 ◦C was also determined to find the reduction in strength at high temperature. Moreover, the compressive and tensile strength of the TSC that had RCA was improved by the addition of bagasse ash.

**Keywords:** bagasse ash; sustainable concrete; sustainable development; mechanical properties; natural coarse aggregate; recycled coarse aggregate; two-stage concrete; materials design; green concrete; recycled concrete
