Preparation and Performance Study of Cracking Resistance High Performance Concrete

The cracking problem of concrete has always been an urgent problem to be solved in engineering. To improve the workability of concrete, reduce hydration heat release, and enhance its crack resistance, a comparative study was conducted on the various properties of concrete with different fly ash dosages, including mechanical properties, thermal properties, and long-term performance. The differences in various properties of concrete with different fly ash dosages were compared and analyzed. The results showed that with the increase of fly ash content, the strength of concrete showed a trend of decreasing in the early stage and rapidly increasing in the later stage.When the fly ash content reached 50%, compared with the specimens without fly ash, its 7-day compressive strength decreased by 40.3%, and the 60 day strength increased by 53.9% compared to the 7-day strength; The addition of fly ash significantly reduces the heat release rate of the cementitious system. The hydration heat release of the cementitious material with a 50% fly ash content after 7 days is 171 J/g, which is 40.3% lower than that of pure cement.; When the water cement ratio is fixed, the addition of fly ash can reduce the shrinkage rate of concrete, and the best shrinkage reduction effect is achieved when the fly ash content is 30%.