Magnesium phosphate cement (MPC) cementitious material is a phosphate cement-based material with strengthformed by a serious of acid-base neutralization reactions among magnesium oxide, phosphate retarder and water,wh...Magnesium phosphate cement (MPC) cementitious material is a phosphate cement-based material with strengthformed by a serious of acid-base neutralization reactions among magnesium oxide, phosphate retarder and water,which has a high early strength and a broad application prospect in the field of pavement rehabilitation. Thisreview collects and organizes the latest progress in the field of research on the influencing factors of mechanicalproperties of magnesium phosphate cementitious materials worldwide in recent years, and discusses the possibilitiesof application in airport engineering.The type of phosphate has a great influence on the reaction products, and the strength of the reaction productsof ammonium salt is higher. Borax is the most commonly used retarder, and the retarding effect is related to theratio of boron to magnesium. However, borax retarders have an adverse effect on the strength of MPC. In terms ofthe influence of mineral admixtures on the properties of MPC, fly ash, silica fume and metakaolin, as commonmineral admixtures, have a positive influence on the mechanical properties of MPC, but the mechanism anddegree of the influence of the three materials on the strength of MPC are slightly different;Aggregates can alsoimprove the volume stability and mechanical properties of MPC by forming skeleton structure and slowing downthe exothermic reaction. In fiber reinforced MPC matrix, steel fiber is the most widely used and the bondingperformance between special-shaped steel fiber and MPC matrix is higher than that of straight fiber;basalt fiberhas also been proved to be used to improve the mechanical properties of MPC system.展开更多
Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods a...Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme conditions.This study developed a framework to evaluate the skid-resistance deterioration of asphalt pavements.In this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of tire.In this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this framework.Compared with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface texture.And the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.展开更多
基金the National Natural Science Foundation of China(Grant No.51908119 and 51890904)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190367)+2 种基金the Natural Key Research and Development Project(Grant No.2020YFB1600102)the National Key R&D Program of China(Grant No.21YFB2600600 and 21YFB2600601)the Postgraduate Research&Practice Innovation of Jiangsu Province(Grant No.KYCX22_0275).
文摘Magnesium phosphate cement (MPC) cementitious material is a phosphate cement-based material with strengthformed by a serious of acid-base neutralization reactions among magnesium oxide, phosphate retarder and water,which has a high early strength and a broad application prospect in the field of pavement rehabilitation. Thisreview collects and organizes the latest progress in the field of research on the influencing factors of mechanicalproperties of magnesium phosphate cementitious materials worldwide in recent years, and discusses the possibilitiesof application in airport engineering.The type of phosphate has a great influence on the reaction products, and the strength of the reaction productsof ammonium salt is higher. Borax is the most commonly used retarder, and the retarding effect is related to theratio of boron to magnesium. However, borax retarders have an adverse effect on the strength of MPC. In terms ofthe influence of mineral admixtures on the properties of MPC, fly ash, silica fume and metakaolin, as commonmineral admixtures, have a positive influence on the mechanical properties of MPC, but the mechanism anddegree of the influence of the three materials on the strength of MPC are slightly different;Aggregates can alsoimprove the volume stability and mechanical properties of MPC by forming skeleton structure and slowing downthe exothermic reaction. In fiber reinforced MPC matrix, steel fiber is the most widely used and the bondingperformance between special-shaped steel fiber and MPC matrix is higher than that of straight fiber;basalt fiberhas also been proved to be used to improve the mechanical properties of MPC system.
基金National Key R&D Program of China(Grant Nos.2021YFB2600601 and 2021YFB2600600)support provided by the Opening Funding Supported by the Key Laboratory of Transport Industry of Road Structure and Material(Research Institute of Highway Ministry of Transport),Beijing,China,the National Natural Science Foundation of China(Grant No.52278444)Postgraduate Research&Practice Innovation of Jiangsu Province(Grant No.KYCX22_0275).
文摘Many rubber friction theories or some method combined theories and field-experiments are employed to evaluate the pavement skid-resistance deterioration due to the evolution of surface textures.However,these methods are difficult to be implemented in the analysis of situations with multi-factor coupling and some extreme conditions.This study developed a framework to evaluate the skid-resistance deterioration of asphalt pavements.In this framework,the portable laser scanning was used to create the digital worn pavement model,and a hydroplaning finite element(FE)model for these digital worn pavements was constructed to evaluate coupling effects of the texture evolution and factors of slip ratio,slip angle,velocity and water film on braking-cornering characteristics of tire.In this study,the deterioration of skid-resistance of five typical asphalt pavements due the surface texture wear was systematically investigated by this framework.Compared with previous works,this study established the rubber friction models for each digital worn pavement considering the energy hysteresis of rubber and the power spectrum density of surface texture.And the rubber friction model was used to define the interaction behaviors between the tire and corresponding wore pavements in the FE hydroplaning model,rather than using an empirical friction model or a fixed friction coefficient.