Different Fine Aggregate Concrete Mechanical Properties and Multi-condition Durability Performance

The mechanical properties and durability of concrete prepared by river sand, machine-made sand and aeolian sand under different working conditions were studied. Combined with the microstructure test, the influence mechanism of different fine aggregates on the performance of concrete was explored. Results show that manufactured sand can improve the mechanical properties of concrete, while aeolian sand reduces the mechanical properties of concrete. Both of them reduce the working performance of concrete. Under the condition of sulfate freeze-thaw dry-wet coupling, the mass loss rate of aeolian sand concrete increases exponentially, which significantly reduces the durability of concrete. The manufactured sand increases the strength of the cement matrix and strengthens the pore structure to increase the proportion of closed pores, which weakens the damage of frost heaving force and crystallization pressure on the pore structure of concrete under the condition of sulfate freeze-thaw and dry-wet coupling, and improves the durability of concrete. Through the life prediction of damage data fitting, it is concluded that manufactured sand improves the durability of concrete under different working conditions, while aeolian sand can only improve the durability of concrete under sulfate freeze-thaw conditions.