Relationship Between Microscopic Pore Structure and Strength of Cement-Based Materials with Low Water-Binder Ratio Under Sulfate Attack Environment

In this paper, the mass loss test, relative dynamic elasticity modulus test, compressive strength test, thermogravimetric analysis (TGA-DTG), and mercury intrusion porosimetry (MIP) were used to study the performance of cement-based materials with low water-binder ratio after sulfate attack, and the influence of microsilica dosage and erosion period on the performance was also investigated. The results indicate that the microsilica mixed can improve the macro- properties of cement-based material with low water-binder ratio after sulfate attack, and as the microsilica dosage is increased, the improvement effect tends to decrease after an increase, while the microsilica dosage is 15%, all performance indexes are the best. This study also demonstrates that the microsilica dosage could affect the mass percent and pore structure distribution of the hydration products of cement-based materials with low water-binder ratio after sulfate attack, and different pore structure distribution may have impact on compressive strength of cement-based materials. Besides, we established relation models for the influence of capillary pores' and gel pores' proportion on the compressive strength of cement-based material after sulfate attack, and concluded that there was no interaction between the impacts of two pore types on compressive strength.