Study on the Influence of Glass Powder Fineness and Substitution Rate on the Microscopic Properties of Cement-Based Materials

The use of glass powder instead of cement as an auxiliary cementitious material can better alleviate environmental problems and energy problems. This experiment studies the influence of the fineness of glass powder and the substitution rate on the performance of mortar, to guide the actual project. The study found that with the increase of the substitution rate, the initial setting time becomes longer, the finer the fineness, the longer the initial setting time, but the difference between P-60 and P-90 decreases with the increase of the substitution rate. With the increase of substitution rate, the compressive strength of 7, 28 and 90 d increased first and then decreased. When the substitution rate was 5%, the compressive strength reached the maximum, but the 7 d compressive strength of P-30 with 5% substitution rate decreased slightly. With the increase of substitution rate, the cumulative hydration heat decreased gradually. The difference between P-60 and P-90 was not significant. Similar to the cumulative hydration heat, the hydration heat flow per gram of cement decreased gradually with the increase of substitution rate. It can be seen from nanoindentation that fineness and substitution rate have little effect on the properties of hydration products. With the increase of substitution rate, the total porosity decreases first and then increases. The porosity of glass powder mixed with P-30 is the largest, followed by P-60 and P-90, but the difference between the total porosity of P-60 and P-90 is not significant. In practical engineering, these two factors need to be considered in combination.