UHPC水化热对功能梯度组合梁早期收缩开裂的影响

Effect of UHPC Hydration Heat on Early Age Shrinkage Cracking of Functionally Graded Composite Beams

以UHPC厚度为基本参量,进行了UHPC-NC功能梯度组合梁水泥水化阶段构件截面温度场和混凝土收缩性能的实验研究。研究表明:当UHPC厚度超过20 mm时,截面中心和外缘的温差达到5.6℃,由温差引起的最大拉应力值为3.36 MPa,组合梁水化热产生的温度应力不可忽略。在试验研究的基础上,提出了考虑UHPC层厚度影响的UHPC-NC功能梯度组合梁温度应力的计算方法,并将计算结果与试验结果进行了对比,两者吻合较好,具有一定的工程应用价值。

The temperature field and the shrinkage performance of the UHPC-NC functional gradient composite beam was carried out,which was based on the UHPC thickness as the basic content in cement hydration stage. The results show that when the thickness of UHPC more than 20 mm,the difference in temperature between the center section and the outer edge reaches 5. 6 ℃,and the difference of maximum tensile stress value caused by temperature is 3. 36 MPa,which proves that beam of hydration heat temperature stress produced can not be ignored. On the basis of experimental research,a calculation method considering the effect of the UHPC UHPC-NC functional gradient layer the thickness of the composite beam temperature stress was put forward. The calculation results are good agreement with real measured data.