Multicomponent cementitious materials optimization, characteristics investigation and reinforcement mechanism analysis of high-performance concrete with full aeolian sand

Aiming at alleviating the shortage issue of high-quality aggregates in deserts, this study developed an eco-friendly concrete using full aeolian sand (hereafter named FA-HPC). Fly ash (FA), silica fume (SF), and slag powder (SP) are introduced into FA-HPC to optimize the performance by single or multicomponent mixing, including fluidity, strength, dry shrinkage, and chloride resistance. Moreover, the reinforcement mechanism is revealed from a microscopic perspective. The results show that FA increases the fluidity of FA-HPC while continuously reducing its drying shrinkage and strength with the dosage increase, presenting a 42.4 % reduction in 3 d compressive strength. On the contrary, SF exhibits a convex parabolic trend in fluidity and strength, achieving a 55.7 % strength improvement at a 10 % dosage, with a gradual increase in dry shrinkage. Additionally, the effect of SP on the performances is relatively small, including the increase in fluidity and strength, and a decrease in shrinkage. In the binary mixing system of FA and SF, an increase in the percentage of SF reduces fluidity and shrinkage resistance. Moreover, a 52.3 % increase in strength can be achieved at an appropriate substitution amount (30 %) and ratio (3:2). Furthermore, triple mixing system of 14.4 % FA, 9.6 % SF and 20 % SP obtains the optimized performance, especially achieving an improvement of 95.5 % in chloride resistance. Additionally, the microstructure and absorption peak indicate that the triple mixing system presents a fierce volcanic ash reaction endowing FA-HPC with improved pore structure and compactness. This research optimized the cementitious material system of FA-HPC and provided technical strategies for engineering construction in desert areas.