早强型基层再生混合料路用性能及施工特性研究

Study on Road Performance and Construction Characteristics of Early-strength Recycled Mixture for Base Course

添加早强水泥能够有效提高乳化沥青再生混合料的早期强度,并减少其强度形成时间。通过室内试验来确定再生混合料的最佳级配、最佳含水量及最佳乳化沥青含量,并对冷再生混合料的力学性能、水稳定性及低温抗裂性能进行研究,最后分析了早强型基层再生混合料的施工工艺及质量控制指标。研究结果表明:(1)冷再生混合料的新旧骨料质量比为2∶8时,最佳含水量为6%,最佳乳化沥青含量为5%。(2)添加早强水泥,能够有效改善冷再生混合料的力学性能。随着水泥含量的增加,冷再生混合料的强度先快速增加、后趋于平缓。添加2%早强水泥时,冷再生混合料早期劈裂强度的增加幅度最大,3 d劈裂强度即可满足下面层要求。(3)相较普通水泥,添加早强水泥对冷再生混合料的水稳定性及低温抗裂性能的改善效果更好。

Incorporating early strength cement can effectively enhance the early strength of recycled asphalt emulsion mixture,and reduce the strength formation time.The optimum gradation,optimum water content and optimum emulsified asphalt content of recycled mixture were determined by laboratory tests.The mechanical properties,water stability and low temperature cracking resistance of cold recycled mixture were studied.The construction technology and quality control index of the early-strength recycled mixture for base were analyzed.The results show that:(1)when the mass ratio of new and old aggregates is 2:8,the optimum moisture content is 6%,and the optimum emulsified asphalt content is 5%.(2)Adding early strength cement can effectively improve the mechanical properties of cold recycled mixture.With the increase of cement content,the strength of cold recycled mixture increases rapidly at first,then tends to level off.When adding 2%early strength cement,the early splitting strength of cold recycled mixture shows the greatest increase,and the 3 d splitting strength could meet the requirements of the lower layer.(3)Early strength cement outperforms common cement in improving water stability and low temperature crack resistance of cold recycled mixture.