Effects of key parameters on fluidity and compressive strength of ultra‐high performance concrete

Abstract

AbstractThe compositions and curing regimes have significant effects on the compressive strength and the fluidity of ultra‐high performance concrete (UHPC). Fifty‐eight mixtures were examined to determine the effects of key factors on the fluidity and the compressive strength of UHPC. These parameters include water‐binder ratio, cement strength, steel fiber content, fly ash content, nanoparticles content, silica fume grade, and curing regimes. The fluidity of UHPC was in the ranges 122–237 mm, while the 28d compressive strength on 70.7 mm cube specimens of UHPC were in the ranges 77–211 MPa. The results showed that fly ash and nanoparticles had significant effects on the fluidity and slight effects on the compressive strength; silica fume grade had slight effects on both the compressive strength and the fluidity; the water to binder ratio, curing regimes, and steel fiber had noticeable effects on the compressive strength. Based on results, the influence coefficients of the investigated key parameters were obtained by regression analysis. Furthermore, the prediction models of the fluidity and the compressive strength of UHPC were proposed by combining the influence coefficients of the investigated key parameters. Therefore, the prediction models can be utilized to optimize the proportions of UHPC mixtures within the ranges of the investigated parameters.