| The scale of highway network of our country is in the top of the world. Cement concrete pavement has proved to be a major and important pavement structure form in China due to its high strength, strong bearing capacity, wide range of applications, abundant raw materials and favorable durability. But in general,cement concrete pavement’s service life is short than expected, many diseases begin to be exposed after only a few years since the practical engineering was put into use,such as crack, cavity,vacancy and the break of plate.All of these diseases need to be repaired by suitable technology to regain the bearing capacity and surface functions. The traditional repairing materials only aim at the sole disease for repairing and it can do nothing to another distress.Common diseases of cement concrete pavement are cracks, broken-off angles, fill block faults diseases, voids, dislocations and that kind of vertical displacement diseases, joint diseases of spalling and explicit, surface cracks and other surface diseases of joints. This thesis is primarily aiming at manufacturing a type of material, which is able to repair quickly most kinds of cement concrete pavement’s diseases mentioned above,named Multifunctional Rapid Repairing Material. On the basis of its optimal formulation and the grasping of its performance, a set of suitable construction process of the materials for it’s engineering promotion has been summed up.Magnesium phosphate cement was chosen as the basic material to develop a multifunction rapid repairing material which is capable of repairing varieties of diseases of cement concrete pavement.Its optimum mix proportion was determined by it’s compressive strength and flexural strength:the ratio of fly ash to the binder wais 20%, and the molar ratio of borax to magnesium oxide was 0.05 and the optimum water to binder ratio was 0.2.The hydration, setting and hardening of MRRM has been discussed. The adjustment function on setting time by adding borax, fly ash or ordinary Portland cement, aluminate cement was investigated respectively; also experiments were carried out to analyze the effect of phosphate and other ammonium dibasic phosphate on extending the setting time from the theory of ionization. The results show that both the borax and fly ash affect the setting time of MRRM slightly. However, the setting time of MRRM can be extended to more than 8minutes when the dosage of the ordinary Portland cement and sulphoaluminate cement is higher than 70%, but result in the flexural strength for one day lower than 1MPa; when the quantity of aluminate cement used is reaching 40%, the setting time can be relayed to more than 10 minutes, and the flexural strength for one day is higher than 4.25MPa; diammonium phosphate can significantly prolong the clotting time to 15 minutes or more, while maintaining a high strength which is above 5MPa.In this thesis, the properties of MRRM mortar were investigated, as well as the sol and rubber powder for MRRM modified role. The best value of water-binder ratio for MRRM’s mortar was 1:1, and if using fine sand preparation, its mortar strength and bonding properties and extending properties was improved a lot. The enhancing effect of the sol on the MRRM is very obvious; using a minor proportion of silica sol to replace the dosage of water can improve flexibility of MRRM. However, if the proportion is more than 20%, the effect to improve flexibility deteriorates; the effect of rubber powder to improve the water resistance and flexibility is especially obvious, and the optimum content of the rubber powder was 5%.Author used the multifunctional rapid repair material supplemented by the large component to analog pavement distress repair application,and assessed the repairing effect; many broken cement pavements and marble staircase was repaired in our compus,and it has achieved good results;on basis of theoretical research and test applications, a unique construction was developed, to promote the application of the multifunctional quick repair material. |
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