Utilization of two stage concreting method in the case of steel slag aggregate concrete

Firstly, developed in the years of 1930, two stage concrete is considered as a unique concreting method that is different from conventional concreting method. The first stage consists of pre-placing coarse aggregates in the formwork and the second stage consists of filling voids between aggregate particle with grout mortar of cement. In this paper, we studied the feasibility of casting two stage concrete with 100 % steel slag as coarse aggregate. In term of formulation, to adopt two stage concreting method we could minimize the risk of concrete bleeding and segregation due to high water absorption and quite high density of slag aggregate. In term of resistance, the evidence of solid cohesion between mortar phase and slag aggregate was revealed on 28 days – cured concrete specimens. And the compressive strength was measured at 28.3 MPa. From that, we discussed on the possibility of slag aggregate concrete for the purpose of large scale recycling steel slag with sustainability.