Effects of Cement Brand on the Macro-performance and Microstructure of Self-compacting Concrete under Freeze-thaw Cycles

抄録

Three self-compacting concrete (SCC) mixtures using different cements from the Xizang Autonomous Region were tested for macro-performance before freeze-thaw cycles (FTCs) via rheological, compressive, and splitting tensile strength tests. After FTCs, mass loss rate, relative dynamic elastic modulus (RDEM), and compressive strength were assessed, with scanning electron microscope and mercury intrusion porosimetry used for microstructural analysis. Damage and service life prediction models based on the Weibull distribution were established using mass loss rate and RDEM as failure indicators. Concurrently, a comprehensive evaluation model was developed, integrating compressive strength, freeze-thaw resistance, and material cost. Results show that cement with large negative zeta potential gives SCC better flowability. Lower total porosity correlates with higher compressive strength before FTCs. After 250 FTCs, compressive strength loss and porosity increase are proportional. Within 200 FTCs, lower porosity reduces mass loss and raises RDEM. After 250 FTCs, fewer harmful and highly harmful pores lead to lower mass loss and better RDEM. Damage models were employed to predict SCC the service life of SCC, followed by comprehensive evaluations of the mixtures. These analyses provide valuable guidance for selecting suitable cement brands for construction projects in the Xizang Autonomous Region.