Experimental Study On The Mechanical Properties Of The Asphalt Concrete Core Wall

Asphalt concrete has excellent anti-seepage performance and good deformability,and has been widely used as an anti-seepage structure in earth-rock dams.During the construction of the asphalt concrete anti-seepage core wall,the combination of the core wall layers is the focus of construction,and it is also the weak link of the core wall structure.During the construction,heating measures are often taken on the cooled joint surface to ensure the quality of the interlayer bonding.With the improvement of the quality of domestic asphalt and the improvement of the mechanization level of construction,the interlayer bonding at the conventional temperature of asphalt concrete has been in the Biliuhe Reservoir Dam The project is applied.The construction quality of hydraulic roller compacted asphalt concrete in DLT5363-2016 is not included in the construction specification due to the lack of relevant strength test verification at conventional temperatures,so the relevant strength test verification of the interlayer bonding quality at conventional temperatures is An urgent problem to be solved.This article focuses on a series of practical problems encountered in the current inter-layer combination of asphalt concrete core walls to carry out related research,for this purpose went to the Nada Reservoir Project and Suwalong Reservoir Project for related tests.In the paving test of the Nada Reservoir Project,the artificial paving method was used to study the anti-seepage performance and mechanical properties of the joint surface under infrared heating and flame torch,as well as infrared heating at 70℃,50℃,30℃ and The anti-seepage and mechanical properties of the joint surface under four different temperatures.In the paving test of Suwalong Reservoir,the mechanical properties of interlayer cold bonding and thermal bonding were studied by mechanical paving on the spot,and the mechanical properties of interlayer bonding under daily continuous construction under multiple working conditions were also studied.By analyzing the above test results,the following main conclusions are drawn:(1)When artificially paving,there is no obvious difference between the mechanical strength and anti-seepage performance of the joint surface under infrared heating and flame torch heating,but infrared heating is superior to flame torch heating in terms of deformability(2)The mechanical properties and anti-seepage performance of the bonding surface under the four bonding temperatures of infrared heating show that the bonding heating temperature of the layer has no obvious relationship with the bonding quality of the layer,the main reason is that the "exhaust" process of the upper asphalt mixture further The temperature of the joint surface rises,which dilutes the heating effect(3)When paving asphalt concrete mechanically,there is no obvious difference in the mechanical properties of the bonding surface whether the cold bonding surface is heated or not,which is consistent with the conclusion of the mechanical performance between the layers under infrared heating at different temperatures(4)In the continuous construction of mechanical paving,the temperature of the bottom asphalt concrete layer is 100～110℃,and the mechanical strength of the joint surface is better than that of the daily construction of the first floor,but the deformation capacity is weaker than the daily construction of the first floor.Deformability of the next test piece.It is recommended that during continuous multi-layer construction,you can wait for the surface temperature to further decrease before proceeding with the construction operation(5)Comprehensive analysis of the research conclusion of the inter-layer combination of the two engineering projects.In the construction of the inter-layer combination of the asphalt concrete core walls of the two engineering projects,the inter-layer cold combination treatment method can be adopted.At the same time,the research results of the strength of its joint surface can provide a reference for the next revision of the specification.