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陈化/表面处治工艺对钢渣及其沥青混合料性能影响研究
【作者】 李鑫;
【作者基本信息】 长沙理工大学 , 交通运输工程(专业学位), 2022, 硕士
【摘要】 钢渣力学性能优异,与沥青粘附性强,具有良好的路用价值,而新渣f-CaO等活性成分含量高,导致其体积稳定性差,是限制其在沥青混合料中应用主要因素。目前主要采用自然陈化处理钢渣,降低其体积膨胀,但该方法时间长、占地大,不利于钢渣快速有效利用。为提升钢渣的利用率,论文采用不同压力条件压蒸陈化处治工艺、不同天数水热陈化处治工艺、硅烷偶联剂表面处治工艺和水泥净浆表面处治工艺对新渣预处理,分析不同处治工艺对钢渣性能影响,并研究不同处治工艺钢渣沥青混合料的路用性能。采用陈化处治工艺,分析压蒸和水热处理对钢渣物理力学性能、化学矿物成分、f-CaO含量以及体积稳定性的处治效果。结果表明,新渣浸水膨胀率和f-CaO含量分别为2.725%和4.1 1%,体积稳定性差;压蒸和水热处治的钢渣吸水率、碱度以及f-CaO含量降低,密度、抗压性、耐磨性以及体积稳定性有所提升;压力达到0.6MPa时,继续提升压力压蒸3h对钢渣f-CaO含量降低和体积稳定性改善的效果减弱;90℃水热2d的钢渣性能明显改善,浸水膨胀率为1.083%,f-CaO为1.82%,各项指标符合路用要求;综合考虑处治能耗、时间和效果最终选择0.6MPa压蒸3h或90℃水热2d预处理钢渣。采用表面处治工艺,分析硅烷偶联剂和水泥净浆对钢渣表观形貌结构、物理力学性能、疏水性、与沥青的粘附性以及体积稳定性的处治效果。结果表明,硅烷偶联剂溶液处理后的钢渣表面形成致密连续的偶联层薄膜,与水滴的接触角达到78.76°,降低钢渣亲水性能,虽然钢渣力学性能无明显改善,但钢渣吸水率和浸水膨胀率降低分别为2.31%和1.383%,并且与沥青保持良好的粘附性;水泥净浆处理后的钢渣,虽抗压性和耐磨性有一定提升,但吸水率和浸水膨胀率分别达到3.12%和3.775%,不满足规范要求。基于陈化和表面处治工艺测试结果,以0.6MPa压蒸3h、90℃水热2d和KH550溶液处治的钢渣制备ARAC-13沥青混合料并测试其路用性能。结果表明,不同处治手段均降低了钢渣对沥青的吸收量,最佳油石比分别降低0.1 1%、0.20%和0.34%;处治后钢渣沥青混合料的高温稳定性、体积稳定性和水稳定性均有所提升。研究成果可为改善钢渣的体积稳定性提供重要参考,也可为钢渣在沥青混合料中推广应用提供科学依据。
【Abstract】 Steel slag has excellent mechanical properties,strong adhesion to asphalt,and good road value.The high content of active components such as new steel slag f-CaO leads to poor volume stability,which is the main factor limiting its application in asphalt mixture.At present,natural aging treatment is mainly used to reduce the volume expansion of steel slag,but this method has long time and large area,which is not conducive to the rapid and effective utilization of steel slag.In order to improve the utilization rate of steel slag,this paper adopts different pressure conditions of autoclave aging treatment process,different days of hydrothermal aging treatment process,silane coupling agent surface treatment process and cement paste surface treatment process to pretreat new steel slag,analyzes the influence of different treatment processes on the performance of steel slag,and studies the road performance of steel slag asphalt mixture with different treatment processes.The effects of autoclave and hydrothermal treatment on physical and mechanical properties,chemical mineral composition,f-content and volume stability of steel slag were analyzed by aging treatment process.The results showed that the immersion expansion rate and f-CaO content of new steel slag were 2.725%and 4.11%,respectively,and the volume stability was poor.The water absorption,alkalinity and f-CaO content of steel slag treated by autoclave and hydrothermal treatment decreased,and the density,compressive strength,wear resistance and volume stability were improved.When the pressure reached 0.6MPa,the effect of further increasing the pressure for 3h on the reduction of f-CaO content and the improvement of volume stability of steel slag was weakened.The properties of steel slag after hydrothermal treatment at 90℃ for 2d are obviously improved,and the immersion expansion rate is 1.083%,f-CaO is 1.82%,and the indexes meet the requirements of road use.Considering the energy consumption,time and effect of treatment,0.6MPa autoclaved for 3h or 90℃ hydrothermal for 2d was selected to pretreat steel slag.The surface treatment process was used to analyze the treatment effect of silane coupling agent and cement paste on the apparent morphology,physical and mechanical properties,hydrophobicity,adhesion to asphalt and volume stability of steel slag.The results showed that a dense and continuous coupling layer film was formed on the surface of steel slag treated with silane coupling agent solution,and the contact angle with water droplets reached 78.76°,which reduced the hydrophilicity of steel slag.Although the mechanical properties of steel slag were not significantly improved,the water absorption rate and immersion expansion rate of steel slag were reduced by 2.31%and 1.383%,respectively,and they maintained good adhesion with asphalt.Although the compressive strength and wear resistance of steel slag after cement paste treatment are improved,the water absorption rate and immersion expansion rate are 3.12%and 3.775%respectively,which do not meet the requirements of the specification.Based on the test results of aging and surface treatment process,ARAC-13 asphalt mixture was prepared by 0.6MPa autoclaved 3h,90℃ hydrothermal 2d and KH550 solution treatment of steel slag,and its road performance was tested.The results show that different treatment methods reduce the absorption of asphalt by steel slag,and the optimal asphalt-aggregate ratios are reduced by 0.11%,0.20%and 0.34%,respectively.After treatment,the high temperature stability,volume stability and water stability of steel slag asphalt mixture were improved.The research results can provide important reference for improving the volume stability of steel slag,and also provide scientific basis for the popularization and application of steel slag in asphalt mixture.
【Key words】 Steel slag; Volume stability; Aging treatment process; Surface treatment process; Expansion inhibition; Road performance;
- 【网络出版投稿人】 长沙理工大学 【网络出版年期】2024年 01期
- 【分类号】TU528