碾压式沥青混凝土心墙高温连续碾压试验研究

Experimental Study on High Temperature Continuous Rolling of Roller Compacted Asphalt Concrete Core Wall

为研究沥青混凝土心墙连续两层施工时基层温度高于现行规范规定90℃碾压对心墙质量的影响,现场进行了基层温度为80、90、100、110℃的连续两层碾压试验,通过现场试验研究了不同基层温度的侧胀变化情况,并结合室内试验探究了其压实性能、抗弯性能、抗拉性能及孔隙率变化规律。试验结果表明,随着基层温度的提高,心墙沥青混凝土侧胀量在逐渐增大,基层沥青混凝土较上层沥青混凝土的侧胀量明显;基层温度为80、90、100℃的心墙沥青混凝土抗压强度、抗弯强度及抗拉强度满足现行规范要求;基层温度为110℃的心墙沥青混凝土抗压强度可达到对照组(基层温度为80、90℃)的90%以上,但其抗弯强度和抗拉强度仅为对照组的50%左右,强度有明显下降,基层温度110℃结合区的孔隙率超过规范值3%。这说明基层沥青混凝土温度在低于100℃进行连续两层碾压,物理力学性能可满足现行规范要求。

In order to study the impact of base temperature higher than 90℃in code on the quality of asphalt concrete core wall during two consecutive layers construction,a two-layer continuous rolling test was carried out at the base temperature of 80℃,90℃,100℃and 110℃.The changes of side swelling of different base temperature were studied through field tests,and the changes of compacting property,bending property,tensile property and porosity were explored in combination with laboratory tests.The experimental results show that with the increase of base temperature,the side swelling of asphalt concrete in core wall increases gradually,and the side swelling of base asphalt concrete is obviously larger than that of upper asphalt concrete.The compressive strength,bending resistance strength and tensile strength of core asphalt concrete at base temperature of 80℃,90℃and 100℃all meet the requirements of the code.The compressive strength of core asphalt concrete at the base temperature of 110℃can reach more than 90%of the control group(the base temperature of 80℃and 90℃),but its bending strength and tensile strength are only about 50%of the control group,and the strength is significantly decreased,among which the porosity of the binding zone at the base temperature of 110℃exceeds the standard value by 3%.It shows that the physical and mechanical properties of base asphalt concrete can meet the requirements of the code when the temperature of base asphalt concrete is rolled in two successive layers at 100℃.