钢渣基道路基层材料设计与路用性能研究

Design and Road Performance Study of Steel Slag Based Road Base Material

为降低西北旱寒区公路沥青路面基层早期开裂问题,并促进工业固体废弃物的循环利用,研究将钢渣替代碎石设计成级配钢渣混合料,并以矿渣粉、粉煤灰、电石渣组成的复合矿物掺合料作为胶结料稳定级配钢渣,形成全固废钢渣基道路基层材料。通过测试钢渣浸水膨胀率、基层材料膨胀率、无侧限抗压强度、干缩应变和抗冻性,分析钢渣基道路基层材料的稳定性、强度增长规律、抗开裂特性与长期稳定性。研究结果表明,高温季节钢渣陈化效果显著,90 d陈化期钢渣膨胀率最大降低38.7%。洒水加速了钢渣陈化,较未洒水下钢渣浸水膨胀率降低幅度最大增大了29.1%。复合矿物掺合料对钢渣混合料的膨胀率有抑制作用,12%掺量下膨胀率降低61.8%。级配钢渣混合料随龄期逐渐形成了强度,加入6%复合矿物掺合料后,类似于二灰稳定材料具有早期强度增长较慢、后期强度增长较快的特点,90 d时较水泥稳定材料强度高出2.1 MPa。对比30 d龄期的干缩应变,级配钢渣混合料的干缩应变较水泥稳定混合料降低74%,钢渣基稳定混合料较水泥稳定混合料降低20%。钢渣基道路基层材料的抗冻性在后期均优于水泥稳定和二灰稳定基层材料。综合可知,钢渣基道路基层材料稳定性和长期耐久性良好,具有较低的收缩性,可降低干旱地区基层早期开裂的可能性。

To reduce the early cracking problem of asphalt pavement base course in arid and cold regions of northwest China and promote the recycling of industrial solid waste,agraded steel slag mixture is designed,and a composite mineral admixture composed of slag powder,fly ash,and carbide slag is used as a binder to stabilize the graded steel slag,forming a full solid waste steel slag based road base material.By testing the water immersion expansion rate of steel slag,the expansion rate of base material,unconfined compressive strength,dry shrinkage strain,and frost resistance,the stability,strength growth rule,cracking resistance,and long-term stability of steel slag based road base material are analyzed.The results show that the aging effect of steel slag in high temperature season is significant,and the expansion rate of steel slag during the 90day aging period decreases by a maximum of 38.7%.Spraying water accelerates the aging of steel slag,and the maximum reduction in the expansion rate of steel slag immersed in water increases by 29.1%compared to that without spraying water.Composite mineral admixtures have an inhibitory effect on the expansion rate of steel slag mixture,and the expansion rate decreases by 61.8%when the content is 12%.Graded steel slag mixture gradually develops strength with age.After adding 6%composite mineral admixtures,it is similar to lime fly ash stabilized materials in that its early strength increases slowly and its later strength increases rapidly.At 90days,its strength is 2.1MPa higher than that of cement stabilized materials.Compared to the dry shrinkage strain at the age of 30days,the dry shrinkage strain of graded steel slag mixture is 74%lower than that of cement stabilized mixture,and the dry shrinkage strain of steel slag based stabilized mixture is 20%lower than that of cement stabilized mixture.The frost resistance of steel slag based road base materials is better than that of cement stabilized and lime fly ash stabilized base materials in the later stage.In conclusion,the steel slag based road base material has good stability and long-term durability,and has low shrinkage,which can reduce early cracking of the base in arid areas.