超细钢纤维增强粉煤灰水泥基材料的力学性能和干缩研究

Mechanical behaviors and drying shrinkage of ultra- fine steel fiber reinforced fly ash cementitious composite

研究了超细钢纤维增强粉煤灰水泥基材料在不同养护条件下的抗压、抗折强度发展,以及其干缩发展规律。试验结果表明:超细钢纤维增强粉煤灰水泥基材料标养28 d及蒸养3 d抗压强度最高可达到106.6和109.4 MPa,蒸养和水浴可提高水泥基材料早期强度。水泥基材料抗压强度随纤维掺量增加先轻微下降后增加,其抗折强度随钢纤维掺量增加而线性增加。钢纤维增强水泥基材料干缩与龄期符合指数函数关系,其15 d最大干缩值为0.000 521 mmmm,其3 d内的干缩应变均达到后期干缩应变的50%以上。钢纤维掺入水泥基材料干缩值最大降低了15.3%,且将干缩值趋于稳定的龄期提前;抗压强度及抗折强度随钢纤维的掺量增加,抗压强度增加值不超过25%,抗折强度最大增加接近50%。

An experimental program was carried out to investigate the influence of curing conditions on the compressive and flexural behaviors of ultra- fine steel fiber reinforced fly ash cementitious composite that drying shrinkage was observed. The results showthat the max compressive strength of ultra- fine steel fiber reinforced fly ash cementitious composite under the curing that 28 d of standard conditions and 3 d of high temperature steam pressure are 106.6 M Pa and 109.4 M Pa,the early strength of cementitious composite is reinforced by the high temperature condition. The compressive strength of ultra- fine steel fiber reinforced fly ash cementitious composite that a slight decline before rising behaviors performed along with the increase of steel fiber,which performed a liner increase on the flexural strength,which the exponential function relationship between times and drying shrinkage performed that the shrinkage value that occupied more than 50%within the 3 d is 0.000 521 mm mm by the 15 d,which the max reducing value reached 15.3% with fiber volume range accelerated stability,which leaded to the compressive strength max value increased by 25% and the flexural strength value increased less than 50%.