道路现场冷再生技术应用研究

【作者】 何林兴；

【导师】 李国芬； 杨咏梅；

【作者基本信息】 南京林业大学 ， 林业工程， 2008， 硕士

【摘要】 目前,国内沥青路面冷再生技术研究处于起步阶段,无论是冷再生混合料性能研究、配合比设计方法还是施工工艺等方面都不成熟。因此,有必要对该技术进行深入系统的研究。道路的现场冷再生,就是常温下将旧路面经过破碎处理后,与再生剂、新稳定剂、新集料等按一定比例重新拌和成混合料,能够满足一定的路用性能并重新铺筑于路面的一整套工艺。加入稳定材料是为了提高再生材料的强度,稳定材料一般可采用水泥、乳化沥青、泡沫沥青等。掺加水泥作为稳定剂,再生得到的混合料作为路面的基层使用。目前,国内冷再生较多采用这种方案,水泥用量一般控制在3%～6%之间。掺加乳化沥青或泡沫沥青作为稳定剂,再生得到的混合料可作为沥青碎石基层或沥青下面层使用。乳化沥青是沥青、水和乳化剂的混合物。使用乳化沥青的好处是其粘度低,易于用再生设备中的液体喷洒装置添加,再生材料与乳化沥青拌和后,乳化沥青破乳,水分从沥青中分离山来,水分在碾压过程中被挤山基层或在养生期蒸发,残留的沥青有较高的粘度,从而提高了旧材料的粘结性。泡沫沥青是高温沥青(140℃以上)遇到冷水滴(环境温度)产生的。使用的沥青为普通针入度级的沥青,如AH-70号普通沥青。当水遇到高温沥青时,发生热量传递,水会迅速蒸发,沥青产生泡沫,体积膨胀至原来的10至20倍。泡沫沥青大大增加了沥青的体积和表面活性,在发泡的过程中,沥青的粘度显并降低,从而使沥青能充分地扩散进骨料中去。由于对旧材料进行重复利用,在施工过程中,路面的几何线形及厚度能得到很好地保持。与其它路面修复技术相比,现场冷再生还能在一定程度上减少连续交通中断的现象。总结起来,道路的现场冷再生有下列优点:①降低施工成本。现场冷再生不需要将材料运到拌和场,然后再将冷再生材料运回施工现场,节约了运输费用和误工时间:②节约集料和沥青胶结料;③保持原路面的几何特性:④保护环境;⑤节约能源:⑥减少用户的延误。另外,路面再生可根据其破坏情况和结构需要选择不同的再生深度和不同的稳定剂。本论文采用德国Wirtgen公司生产的WR2500型冷再生设备。该设备充分利用原有的路面材料,并加入一定量的稳定剂,在自然条件下一次性连续地完成材料的铣刨、破碎、拌和、摊铺及碾压等工艺。根据旧路调查和FWD弯沉测试结果,确定再生深度,形成了水泥全深度冷再生、泡沫沥青全深度冷再生和泡沫沥青再生旧路面层三种冷再生方案。在参考国内外冷再生技术研究成果的基础上,确定了稳定剂最佳剂量的选择方法,初步形成冷再生混合料的配合比没计方法。铺筑试验路,总结了现场冷再生技术施工工艺和质量控制方法,并且对试验路进行了跟踪观测,对冷再生技术进行经济技术分析。最后,本文提出了研究的主要结论及建议。1.通过对水泥全深度再生和泡沫沥青全深度再生测定其试件的无侧限抗压强度和弹性模量,来确定稳定剂的最佳剂量是可行的:采用马歇尔的试验方法来确定混合料的泡沫沥青最佳用量也是可行的。再生混合料的级配可以通过加入适量新集料以提高其结构强度,考虑到施工因素,新集料不易过多,不超过再生料质量的60%为宜。2.本论文对90号沥青进行了发泡试验,发泡温度取160℃,用水量取2.5%,膨胀率为15倍,半衰期为10秒。3.推荐水泥全深度冷再生配合比设计标准为:无侧限抗压强度代表值大于1.5MPa,弹性模量平均值大于1000MPa。4.推荐泡沫沥青全深度冷再生配合比设计标准为:无侧限抗压强度代表值大于1.2MPa,弹性模量平均值大于1500MPa。5.对于面层泡沫沥青冷再生的配合比设计方法采刚马歇尔试验,找出与最大稳定度、最大密度及目标空隙率中值对应的二个泡沫沥青用量,求其平均值,得到最佳泡沫沥青用量初始值,综合分析得到最佳泡沫沥青用量。6.论文对泡沫沥青混合料做了加1%水泥和不加水泥两组对比试验,结果表明,加1%水泥的泡沫沥青混合料强度明显高于不加水泥的,后者稳定度过低,不予采用。7.含水量对泡沫沥青混合料稳定度影响试验表明:含水量越高,泡沫沥青混合料稳定度越低。但是含水量与施工和易性成正比,含水量又不过低。结合Wirtgen推荐的经验公式,本论文将含水量控制在5%左右。8.泡沫沥青混合料的密度为2.200g/cm3左右,与普通沥青混合料约2.400g/cm3相比,略低。这是由于泡沫沥青是以颗粒状黏附在集料表面,而不是像普通沥青混合料那样沥青完全包裹集料。这使得泡沫沥青混合料劈裂强度很差,水稳定性也较差,所以泡沫沥青再生层都要用普通沥青混凝土罩面。本论文对泡沫沥青混合料做了冻融劈裂试验,试验结果充分证明上述结论。9.泡沫沥青混合料不易压实,面层泡沫沥青再生试验段压实度约为90%。施工时应适当增加压实功。更多还原

【Abstract】 At present, studying the technology of asphalt pavement recycling is only a start. Studying of Cold Recycled mix performance, gradation design method, construction technologies and so on should to be study more.The path scene cold regeneration, after is under the normal temperature passes through stave processing the old road surface, with the regenerant, the new stabilizer, the new aggregate and so on mixes up the blend according to certain proportion, can satisfy certain road and lays with the performance in the road surface one whole set craft.Joins the stable material is in order to enhance the breeder material the intensity, the stable material may use the cement, the emulsified bitumen, the froth asphalt generally and so on.Mixes adds the cement to take the stabilizer, the regeneration obtains the blend takes the road surface the basic unit use.At present, the domestic cold regeneration uses this kind of plan, the cement content general control between 3%～6%.Mixes adds the emulsified bitumen or the froth asphalt takes the stabilizer, the regeneration obtains the blend may take under the oil coated stone basic unit or the asphalt the surface layer use.The emulsified bitumen is the asphalt, the water and the emulsifier mixture.The use emulsified bitumen advantage is its viscosity is low, easy sprays the installment with the regenerative equipment in liquid to increase, after the breeder material and the emulsified bitumen mix up, the emulsified bitumen emulsion breaking, the moisture content separates from the asphalt, the moisture content is squeezed out in the roller compaction process the basic unit or evaporates in the keeping in good health time, the residual asphalt has the high viscosity, thus enhanced the old material cohesiveness.The froth asphalt is the high temperature asphalt (140℃above) meets the cold waterdrop (ambient temperature) to produce.Use asphalt for ordinary penetration level asphalt, like AH-70 number ordinary asphalt.When the water meets the high temperature asphalt, has the thermal transmission, the volunteer fire brigade rapid evaporation, the asphalt frothing, the volume expansion to original 10 to 20 times.The froth asphalt increased the asphalt volume and the surface activity greatly, in the foaming process, the asphalt viscosity obviously reduces, thus enables the asphalt to proliferate in fully the aggregate.Because carries on the reuse to the old material, in the construction process, the road surface geometry linear and thickness can obtain maintains well.Compares with other road surface repair technology, the scene cold regeneration also can reduce the continual traffic interruption to a certain extent the phenomenon. Summarizes, the path scene cold regeneration has the following merit:①Reduces the construction cost.The scene cold regeneration does not need to transport the material the mixing plant, then ships back again the cold breeder material the job location, saved the cartage expense and the delaying work time;②Saves the aggregate and the bituminous cement;③Maintenance old route surface geometry characteristic;④Protection environment;Saves the energy;⑥Reduced user’s delay.Moreover, the road surface regeneration may needs to choose the different regeneration depthand the different stabilizer according to its destruction situation and the structure.This topic uses the WR2500 cold regenerative equipment which German Wirtgen Corporation produces.This equipment full use original road surface material, and joins the ration the stabilizer, disposable completes the material under the natural condition the mill to dig continuously, stave, mixes up, spreads paving and crafts and so on roller compaction.According to the result of investigating old pavement and deflection test, the recycling depth is ascertained. Then three schemes are decided. They are full depth reclamation with cement stabilized, full depth reclamation with foamed asphalt stabilized and the reclamation of old asphalt pavement with foamed asphalt stabilized. After studying the present situation of cold recycling, the method of how to choose the optimum content of stabilizers is confirmed. And the gradation design method of cold recycled mixture is put forward. After paving the test road, construction technologies and quality control methods are concluded. There is three times of road testing and techno-economic analysis of cold recycling.1. Through determines its test sample to the cement entire depth regeneration and the froth asphalt entire depth regeneration the non-side to limit the compressive strength and the elasticity coefficient, determined the stabilizer the best dosage is feasible; Uses Marshall’s testing method to determine the blend the froth asphalt best amount used also is feasible.The regeneration blend gradation may through join the right amount new aggregate to enhance its structural strength, considered the construction factor, new aggregate Yi Guoduo, do not surpass again the crude material quality 60% for suitably.2. This topic carried on to 90 asphalt became spongy the experiment, the foaming temperature took 160°C, the water consumption took 2.5%, the expansion rate is 15 times, the half-life is 10 seconds.3. The recommendation cement entire depth cold regeneration mixture ratio design standard is: Limits a compressive strength generation of tabular value without the side to be bigger than 1.5MPa, the elasticity coefficient mean value is bigger than 1000MPa.4. The recommendation froth asphalt entire depth cold regeneration mixture ratio design standard is: Limits a compressive strength generation of tabular value without the side to be bigger than 1.2MPa, the elasticity coefficient mean value is bigger than 1500MPa.5. Uses Marshall regarding the surface layer froth asphalt cold regeneration mixture ratio design method to experiment, discovers with the greatest stability, in the greatest density and the goal percentage of voids the value correspondence three froth asphalt amount used, asks its mean value, obtains the best froth asphalt amount used starting value, the generalized analysis obtains the best froth asphalt amount used.6. The topic-based group did to the froth bituminous mixture added 1% cement and does not add the cement two group of contrast experiments, finally indicated, added 1% cement the froth bituminous mixture intensity to be higher than obviously does not add the cement, the latter passed stably lowly, did not give the use.7. The water content indicated to the froth bituminous mixture stability influence experiment that,The water content is higher, the froth bituminous mixture stability is lower.But the water content and the construction workability are proportional, water content low.Unifies the Wirtgen recommendation the empirical formula, this topic water content control about 5%.8. The froth bituminous mixture density is about 2.200g/cm3, compares approximately with ordinary bituminous mixture 2.400g/cm3, slightly low.This is because the froth asphalt is by granulated adheres in the aggregate surface, but the ordinary bituminous mixture such asphalt completely wraps the aggregate likely.This causes the froth bituminous mixture cleavage strength to be very bad, the water stability is also bad, therefore the froth asphalt regeneration zone all must use the ordinary asphalt concrete surface coating.This topic has performed the freezing and thawing split test to the froth bituminous mixture, the test result full proof above conclusion.9. The froth bituminous mixture not easy compaction, surface layer froth asphalt regeneration test section compactness is approximately 90%.When construction should increase the compaction merit suitably.更多还原