| The repair of cement concrete pavement diseases such as potholes and cracks hasbeen given great attention by domestic and foreign research institutions andengineering units. In the paper, through methods such as theoretical analysis,experimental research and numerical calculation, it was thoroughly researched thatthe repair materials and methods for potholes and cracks of concrete pavement.Moreover, some application experiments were carried out basing on QinglianExpressway in Guangdong Province.The paper develops a series of researches using ultra-short ultra-fine steel fiberreinforced concrete as new repair material of potholes and using newly modifiedepoxy resin with excellent rheological property as crack repair material. Main workand conclusions includes:①By orthogonal test of steel fiber reinforced concrete of different types andcontents, mix proportion of ultra-short ultra-fine steel fiber reinforced concrete forpavement potholes repair is optimized. Researches show that3d flexural strength ofthe new repair material can reach6.7MPa, and its corresponding compressive strengthcan reach40~50MPa, which can help achieve rapid repair of pavement. In themeantime,28d flexural strength of the material can reach12.4Mpa, and its28dcompressive strength can reach70Mpa, which is significantly enhanced comparingwith ordinary cement concrete.②By experiments concerning to the flexural toughness, fracture toughness andimpact toughness of steel fiber reinforced concrete, it was found that the influence ofage to the strength index of steel fiber reinforced concrete was great, but its influenceon the toughness index is not obvious. The flexural toughness of ultra-short ultra-finesteel fiber is significantly improved comparing to it of ordinary concrete, especiallythe I5, I10and I20are improved by113%、296%、464%respectively. Also, thedeformation coordination capacity as well as fracture toughness of the ultra-shortultra-fine steel fiber concrete is improved significantly, which enhances the KICof thesteel fiber reinforced concrete by288%comparing with it of the ordinary concretebestowing it with excellent fracture toughness. Meanwhile, the incorporation of steelfibers is not only can delay the initial cracks, but also can greatly slowing down thedevelopment rate of cracks, allowing the cement material with extraordinary impacttoughness which is increased by8-11times of the impact toughness of ordinaryconcrete. ③The adhesive property of old and new kinds of concrete is studied. Resultsshow that: the bonding strength of the adhesive homemade by the research group canreach3.48Mpa, and its interfacial tensile strength is above4.5Mpa. Under the sameexperimental conditions, its strength is higher than normal cement adhesives for morethan3times.④Preliminary experiments were carried out concerning to the new repairingmaterial. Studies show that crack repairing strength of epoxy material is the best, butits grouting effect is poor and its bond strength is low in moisture circumstances. Byregulating the mobility of modified epoxy, both its grouting depth and sealed effectcan be guaranteed, also the bond strength of the material in moisture circumstancescan be ensured achieving satisfactory results.⑤The finite element analysis of actual situation of potholes repair is carried outthrough the finite element software. At the same time, the actual vehicle loadsupported by the repaired road is mechanical analyzed under different workingconditions. The results show that: the bonding capacity of the interface adhesivehomemade by the group is far greater than the interfacial stress obtained bytheoretical calculations; with the same circumstances, the increase of the thickness ofrepair material at the pothole will get a better repair effect. However, taking therequirements such as actual construction process and cost into account, pothole repairdesign should consider under the premises of force, construction and cost for rationaldesign. |
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