低温环境下水泥稳定碎石基层施工车辆轴载控制

Vehicle Load Control of Cement Stabilized Macadam Based on Low Temperature Environment

低温环境下半刚性基层强度形成缓慢,造成养护时间增加,进而使工期大大延长,工程成本增加。为尽早开放交通,研究了低温环境下水泥稳定碎石基层施工期间车辆轴载对基层结构的影响,并得到了施工期间车辆的控制轴载。首先对低温养护环境下掺加早强剂的水泥稳定碎石材料进行室内力学性能试验,得到养护温度、早强剂掺量以及养护龄期等因素对劈裂强度与压缩模量的影响,其次通过使用KENPAVE软件对材料进行力学分析,比较层底最大拉应力与抗弯拉强度,最后得出施工车辆轴载控制。研究结果表明:在低温养护环境下,早强剂掺量越大,水泥稳定碎石材料的劈裂强度与压缩模量越大;在低温条件下,对于分层不连续摊铺施工方案,底基层养护7、14 d后,施工车辆对底基层产生的层底拉应力均大于抗拉弯强度;对于连续摊铺施工方案,通过数据计算得出回归方程,为施工过程中施工车辆轴载的控制提供了依据。

The strength of the semi-rigid base layer is slow in the low temperature environment,which increases the curing time,greatly prolongs the construction period and increases the engineering cost.In order to open traffic as early as possible,the influence of vehicle axle load on the base structure during the construction of cement stabilized macadam base under low temperature environment was studied,and the control axle load of the vehicle during construction was obtained.Firstly,the indoor mechanical properties of cement stabilized macadam materials with early strength agent in low temperature curing environment were tested.The effects of curing temperature,early strength agent dosage and curing age on the splitting strength and compressive modulus were obtained.The mechanical analysis of the material was carried out by using KENPAVE software,and the maximum tensile stress and bending strength of the layer were compared.Finally,the axle load control of the construction vehicle was obtained.The results show that under the low temperature curing environment,the larger the amount of early strengthening agent,the greater the splitting strength and compressive modulus of cement stabilized macadam material;under low temperature conditions,for the layered discontinuous paving construction scheme,after the foundation layer is cured for 7 d and 14 d,the layer bottom tensile stress generated by the construction vehicle on the subbase layer is greater than the tensile strength;for the continuous paving construction scheme,the regression equation is obtained through data calculation,which provides a basis for the control of the axle load of the construction vehicle during the construction process.