Optimization for Mix Proportion of Reactive Powder Concrete Containing Phosphorous Slag by Using Packing Model

Abstract

A mix-design method based on packing model was used to optimize the mix proportion of Reactive Powder Concrete (RPC) containing phosphorous slag in this paper. The design aimed to achieve a densely compacted matrix by applying the modified Andreasen particle packing model, i.e., the Dinger-Funk particle size distribution (PSD) equation. MATLAB and Excel Solver Tool were utilized to implement the calculation of the design with four steps. The outcome of the design was quite similar to another two results obtained respectively through the method for minimum water demand of paste and through the orthogonal design for mix proportion of RPC. According to these three mix proportions, RPC specimens with volume fraction of steel fiber of 1% were produced after they had been cured in 95°C steam for 72 hours. Their compressive and flexural strength are more than 180 MPa and 28 MPa, respectively. Microstructural investigation of specimens through mercury intrusion porosimetry and scanning electron microscopy confirms the very low porosity and quite compact microstructure of the RPC.