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为研究夹层、裂缝、加载方式对旧水泥路面沥青加铺结构沥青层底受力的影响,制作无裂缝有夹层、有裂缝无夹层、有裂缝有夹层3种试件,采用反力架装置和千斤顶施加荷载,在沥青层底粘贴应变片,通过电阻应变仪和电脑自动记录沥青层底的受力.针对各种工况,绘制了沥青层底的应力与外加荷载关系曲线,拟合了相应的数学关系式,求出了一些关键的沥青层底拉应力.研究表明:外荷载小于0.8 MPa时沥青层底受力状态较好;无缝有夹层的罩面结构沥青层底拉应力最小,加载至1.4 MPa时,层底拉应力仍然低于容许应力;当施加1.4 MPa的荷载时,夹层能减小沥青层底应力40.54%,裂缝能增加沥青层底应力46.67%,偏载能增加沥青层底应力100%.因此,旧水泥路面沥青加铺罩面工程,需要填补既有裂缝、设置防裂夹层、避免偏向受力、车辆荷载最好控制在0.8 MPa以下,才能降低沥青层底拉应力,保证工程质量.
In order to study the influence of interlayer, crack and loading method on the stress of asphalt concrete pavement with asphalt overlay, three kinds of specimens with no cracks, no cracks and no cracks with cracks were made. The strain is applied to the asphalt layer and the stress of the asphalt layer is automatically recorded by the resistance strain gauge and the computer.According to various working conditions, the curve of the stress on the asphalt layer and the applied load is plotted, The results show that the stress state of asphalt layer is better when the external load is less than 0.8 MPa, the tensile stress of the asphalt layer with the seamless overlay structure is the smallest, When 1.4 MPa load is applied, the tensile stress of the bottom layer is still lower than the allowable stress. When the load of 1.4 MPa is applied, the interlayer stress of the asphalt layer can be reduced by 40.54%, the crack can increase the stress of the asphalt layer by 46.67% Therefore, the old cement pavement asphalt overlay engineering, need to fill the existing cracks, set anti-crack sandwich, to avoid biased force, the best vehicle load controlled below 0.8 MPa, in order to reduce the bitumen layer pull should Ensure project quality.