Application of Statistical Analysis for Mixture Design of High-Strength Self-Consolidating Concrete Containing Metakaolin

摘要

A statistical design of experiments method was applied to optimize the mixture proportions of high-strength self-consolidating concrete (SCC) incorporating metakaolin (MK). The optimization involved varying three mixture factors (variables) at five different levels. These factors included total binder content, percentage of MK in the mixture, and water-to-binder ratio. The statistical analysis was exploited to determine the most significant factors affecting the properties of SCC and the optimum level of each variable. A total of 27 mixtures were tested at both the fresh and hardened states to obtain the best SCC mixture containing MK and to compare its results with SCC mixtures containing other supplementary cementing materials. The fresh properties tests included slump flow, V-funnel, L-box, J-ring, and air content tests. On the other hand, at 28 days, the compressive strength of SCC samples under two curing regimes was evaluated. The results showed that the optimized high-strength SCC mixture had a superior performance in the fresh and hardened states compared with the SCC mixtures containing silica fume, fly ash, or slag. The results of the numerical optimization for SCC mixture containing MK showed optimum levels of total binder content of 490 kg/m~3, water-to-binder ratio of 0.39, and replacement of cement by MK of 19.9%. The results also showed that MK replacement proved to be the most significant factor affecting the 28-day compressive strength of all tested mixtures regardless of curing techniques.