Effects of Temperature and Curing Methods on the Pore Structure and Mechanical Properties of Multi-Admixture Concrete

To elucidate the relationship between concrete pore structure and mechanical properties under multiple factors, the response surface methodology (RSM) was employed to optimize the mix design. Combined with XRD and various characterization techniques, this study investigated the influence of temperature (0°C, 20°C, 40°C), curing method (standard curing, water-sprinkling curing, film curing), and mix design on concrete pore structure (pore chord length distribution, porosity, etc.) and mechanical properties. Results indicate: Temperature regulates pore structure through dual effects of capillary pressure hardening and temperature stress deterioration. Low temperatures favor micro-pore formation, while high temperatures tend to cause large-pore series connections. Curing method influences hydration processes via moisture replenishment stability, thereby altering pore parameters. Standard curing yields optimal results, water sprinkling serves as an effective alternative, and film curing leads to pore structure deterioration due to insufficient moisture. The fly ash-granulated blast furnace slag-foam suppressant blended system (H0) significantly optimizes pore structure under various temperatures and curing conditions through synergistic effects. It increases the proportion of micro-pores while reducing large-pore content, thereby enhancing mechanical properties and thermal expansion adaptability. The core principle is: “Higher micro-pore proportion and lower large-pore proportion correlate with superior mechanical performance.”