Optimized design of ultra-high performance concrete matrix based on multifactor interaction
摘要
Renowned for its outstanding strength, durability, and resistance to cracking, ultra-high performance concrete (UHPC) relies on the careful selection of materials and mix design to achieve the ideal combination of extreme strength and fluidity. This study utilized the simplex centroid design (SCD) method to conduct a multifactor interaction analysis aimed at optimizing the mix proportion of UHPC matrix. The optimized UHPC was then evaluated for its performance. Statistical models were developed to examine the connections between the characteristics (including fluidity, flexural and compressive strength) and the proportions of cement, silica fume, fly ash, and sinking beads of the UHPC matrix employing the SCD method. The models considered four cementitious materials and their interactions. Analysis of variance (ANOVA) was utilized for validation, resulting in the generation of response surfaces and contour plots. These visualizations offered insights into the effect of individual and interactive variables on UHPC matrix performance. Subsequently, the test mix proportions were determined according to the specified performance requirements, and end-hooked steel fibers were incorporated into the mixtures to produce UHPC. The thoroughly evaluated optimized UHPC showed enhanced workability, mechanical properties, durability, and microstructural characteristics. Furthermore, it exhibited improved resistance to chloride ion penetration and superior long-term drying shrinkage behavior when compared to standard concrete.