PVA-ECC复合无接缝水泥混凝土路面施工技术研究

Research on Construction Technology of PVA-ECC Composite Jointless Cement Concrete Pavement

为进一步研究并解决传统水泥混凝土路面切缝造成的耐久性和行车舒适性问题,考虑到PVA-ECC材料的优良性能,文章依托河北省某重点高速公路项目,将该新材料应用到服务区水泥混凝土路面施工中。运用ABAQUS软件建立了PVA-ECC罩面型与补丁型两种复合无接缝水泥混凝土路面结构分析模型,进行了温度-荷载耦合作用下的敏感性分析,分析了土基模量、PVA-ECC模量、PVA-ECC厚度、水泥板模量、水泥板厚度等动力响应规律。研究发现,罩面型路面结构的最大耦合弯拉应力受罩面层厚度与PVA-ECC模量的影响较大,补丁型路面结构的最大弯拉应力受模量的影响较大。通过试验段现场实测与理论模拟情况比对分析,验证了ECC混凝土的抗压性能可以满足传统抗压使用要求,同时实际测试和理论模拟得到的拉应变数值都远小于资料显示的PVA纤维混凝土0.5%极限拉应变,最终得出PVA-ECC复合无接缝水泥混凝土路面ECC结构层最佳层厚为7 cm,满足使用要求且能达到消除混凝土接缝的效果,该研究成果可为PVA-ECC材料的推广应用提供参考。

In order to further study and solve the durability and driving comfort problems caused by the cutting joint of traditional cement concrete pavement,considering the excellent performance of PVA-ECC material,this paper applies this new material to the construction of cement concrete pavement in the service area based on a key expressway project in Hebei province.In this paper,ABAQUS software is used to establish the structural analysis models of PVA-ECC overlay-type and patch-type composite jointless cement concrete pavement.The sensitivity analysis under the temperature-load coupling effect is carried out,and the dynamic response laws such as soil modulus,PVA-ECC modulus,PVA-ECC thickness,cement slab modulus,and cement slab thickness are analyzed.It is found that the maximum coupling flexural tensile stress of overlay pavement structure is greatly affected by the thickness of overlay layer and PVA-ECC modulus,and the maximum flexural tensile stress of patch pavement structure is greatly affected by the modulus.Through the comparison and analysis of the field measurement and theoretical simulation of the test section,it is not only verified that the compression performance of ECC concrete can meet the traditional compression requirements,but also verified that the tensile strain values obtained from the actual test and theoretical simulation are far less than the 0.5%ultimate tensile strain of PVA fiber concrete shown in the data.Finally,the optimal layer thickness of the ECC structural layer of PVA-ECC composite jointless cement concrete pavement is 7 cm,which meets the requirements of use and can achieve the effect of eliminating concrete joints.The research results can provide reference for the promotion and application of PVA-ECC materials.