旧沥青路面全深式冷再生基层材料力学性能
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摘要
为研究应用旧沥青路面材料冷再生基层的混合料力学性能,回收原沥青路面面层旧料和基层旧料,制备沥青路面全深式冷再生基层材料,结合现场沥青面层及铣刨深度测试冷再生材料级配,测试冷再生基层材料的7 d无侧限抗压强度、90 d劈裂强度和90 d回弹模量,并观察其SEM微观形貌图。结果表明:水泥用量较少时7 d无侧限抗压强度、90 d劈裂强度和90 d回弹模量均随水泥剂量的增加快速增长,但是增长趋势逐渐变缓;较少的沥青旧料对再生基层力学性能是有利的,但是过多的沥青旧料则会产生较大的负面影响;当面层旧料的油石比较小时,水泥水化物取向结晶能刺破沥青膜层,直接与裹附在沥青内部的集料接触,形成较强的界面,这样能有效缓解沥青对强度的负面影响。进而建议低等级公路的中、轻型交通等级水泥剂量在5%~7%,其他类型公路则在提高水泥剂量的同时需要改善旧料级配;油石比小的旧沥青路面改造更适合推行全深式冷再生基层技术。
In order to analyze the mechanical properties of cold regenerated base mixture from old asphalt pavement,the old material of original asphalt pavement and base was recycled to prepare the full depth base mixture. Combined with on-site asphalt surface layer and milling depth,the gradation of cold regenerated base mixture was analyzed. The 7 d unconfined compressive strength,90 d splitting strength and 90 d modulus of resilience of the mixture were tested,and the SEM morphology of the mixture was observed. The results show that,when less amount of cement content was used,the 7 d unconfined compressive strength,90 d splitting strength and 90 d resilient modulus of the mixture increase rapidly with the growth of the cement dosage,while the growth is becoming slowly;that it would benefit the mechanical properties of reclaimed base if a small quantity of RAPs were used,but excessive RAPs would cause negative effect; that,when the asphalt proportion in the surface RAP is small,the orientation crystallization of cement hydrates can prick the asphalt film and contact directly with aggregate coated with the asphalt film,which forms strong interface,and the negative effect of asphalt on strength was mitigated. The amount of 5% ~ 7% cement by weight of the mixture is recommended for use in low grade and light traffic highways,and higher percentage of cement is recommended for other highways while the gradation of reclaimed aggregate should be improved. Asphalt pavement with lower oil stone ratio is more suitable to use the cold regenerated base.
In order to analyze the mechanical properties of cold regenerated base mixture from old asphalt pavement,the old material of original asphalt pavement and base was recycled to prepare the full depth base mixture. Combined with on-site asphalt surface layer and milling depth,the gradation of cold regenerated base mixture was analyzed. The 7 d unconfined compressive strength,90 d splitting strength and 90 d modulus of resilience of the mixture were tested,and the SEM morphology of the mixture was observed. The results show that,when less amount of cement content was used,the 7 d unconfined compressive strength,90 d splitting strength and 90 d resilient modulus of the mixture increase rapidly with the growth of the cement dosage,while the growth is becoming slowly;that it would benefit the mechanical properties of reclaimed base if a small quantity of RAPs were used,but excessive RAPs would cause negative effect; that,when the asphalt proportion in the surface RAP is small,the orientation crystallization of cement hydrates can prick the asphalt film and contact directly with aggregate coated with the asphalt film,which forms strong interface,and the negative effect of asphalt on strength was mitigated. The amount of 5% ~ 7% cement by weight of the mixture is recommended for use in low grade and light traffic highways,and higher percentage of cement is recommended for other highways while the gradation of reclaimed aggregate should be improved. Asphalt pavement with lower oil stone ratio is more suitable to use the cold regenerated base.
引文
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[10]李宏波,杨明成,刘占江.废旧沥青砼稳定碎石力学性能参数敏感性分析[J].广西大学学报(自然科学版),2014,39(1):112-118.
[11]冯忠居,张永清.粗粒土路基的压实试验[J].长安大学学报(自然科学版),2004,24(3):9-12.
[12]刘勇.对回收路面基层材料的再利用[J].混凝土,2009,24(9):75-78.
[13]胡宗文.冷再生沥青路面材料性能及结构组合研究[D].西安:长安大学,2012.
[14]马君毅.冷再生旧沥青路面材料在基层中的应用研究[D].西安:长安大学,2005.
[2]徐东,陈祥峰,郑南翔.乳化沥青冷再生混合料配合比设计及性能分析[J].广西大学学报(自然科学版),2012,37(1):103-109.
[3]杨宇亮,孙立军,毛如麟,等.回收旧沥青混合料再生技术的研究[J].公路交通科技,2002,19(6):38-40.
[4]徐剑,黄颂昌,秦永春,等.乳化沥青和泡沫沥青冷再生混合料性能研究[J].公路交通科技,2010,27(6):20-24.
[5]耿九光,陈忠达,李龙,等.水泥—乳化沥青再生混合料配合比设计[J].长安大学学报(自然科学版),2009,29(1):10-14.
[6]陈晋华.旧沥青路面材料再生技术研究[J].长沙大学学报,2014,28(5):38-40.
[7]MA Bao-guo,WANG Hai-feng,WEI Ding-bang.Performance of RAP in the system of cold inplace recycling of asphalt pavement[J].Journal of Wuhan University of Technology Mater,2011,26(6):1211-1214.
[8]JENKINS K.Mixture design considerations for cold and half-warm bituminous,mixes with emphasis on foamed bitumen[D].Stellenbosch,SA:University of Stellenbosch,2000.
[9]RAMZI T,ALI A H,KHALID A S,et al.Cement stabilization of reclaimed asphalt pavement aggregate for road base and subbases[J].Journal of Materials in Civil Engineering,2002,14(3):239-245.
[10]李宏波,杨明成,刘占江.废旧沥青砼稳定碎石力学性能参数敏感性分析[J].广西大学学报(自然科学版),2014,39(1):112-118.
[11]冯忠居,张永清.粗粒土路基的压实试验[J].长安大学学报(自然科学版),2004,24(3):9-12.
[12]刘勇.对回收路面基层材料的再利用[J].混凝土,2009,24(9):75-78.
[13]胡宗文.冷再生沥青路面材料性能及结构组合研究[D].西安:长安大学,2012.
[14]马君毅.冷再生旧沥青路面材料在基层中的应用研究[D].西安:长安大学,2005.