膨胀剂及陶砂对UHPC抗冲磨性能和体积稳定性的影响

Effect of Expansion Agent and Pottery Sand on UHPC Anti-wear Performance and Volume Stability

根据UHPC具有较好的抗冲磨性能和收缩大的问题,研究了不同种类、掺量的膨胀剂和陶砂对UHPC抗冲磨性能和体积稳定性(收缩)的影响规律,通过力学性能、长期性能等测试方法对其性能进行分析。研究结果表明,在相同条件下,随着饱水预湿高强陶砂体积掺量提高,UHPC收缩减小,但抗冲磨强度下降,陶砂的体积掺量应控制在10%~20%;掺入CaO类膨胀剂,可以显著降低UHPC的收缩。随着膨胀剂掺量的增加,其补偿了UHPC胶凝材料水化产生的收缩,使混凝土的收缩大大减少。但膨胀剂掺量过高达到8%后,部分膨胀剂无足够的水发生水化反应,其体积稳定性反而不如膨胀剂掺量为6%的试样。预湿陶砂内养护和膨胀剂补偿收缩的协同作用显著降低UHPC的收缩。

According to the good anti-wear performance and the large shrinkage problem of UHPC,the influence of different kinds and amount of expansion agent and pottery sand on UHPC anti-wear performance and volume stability(shrinkage)were studied.Analysis of its performance by test methods such as mechanical properties and long-term performance.Research indicates that under the same conditions,with the increase of volume of saturated pre-wet high-strength pottery sand,UHPC shrinkage decreases,but the anti-wear strength decreases,and the volume of pottery sand should be controlled at 10%-20%.The incorporation of a CaO-based expansion agent can significantly reduce the shrinkage of UHPC.As the amount of expansion agent increases,the expansion agent compensates for the shrinkage caused by the hydration of the UHPC cementitious material,which greatly reduces the shrinkage of the concrete.However,if the amount of expansion agent is too high to 8%,the partial expansion agent does not have enough water to hydrate,and the volume stability is not as good as that of the sample with the expansion agent content of 6%.The synergistic effect of the pre-wet pottery sand inner curing and the expansion agent compensation shrinkage significantly reduces the shrinkage of UHPC.