| When Chinese-funded enterprises carry out foreign aid construction projects,because the corresponding structural design and material design methods of different countries are very different,in the process of project development,designers inevitably face a primary problem:The knowledge of local roadbed pavement design and test technical standards can not be effectively combined with local actual conditions,and can be flexibly applied according to local conditions.In view of the above problems,this paper takes asphalt concrete and semi-rigid materials as examples to study the differences between Chinese and French design methods and road performance.First,in terms of asphalt concrete,for the BBSG and GB4 mix used in the TT Expressway,The differences in the method of designing the medium mix ratio of asphalt mixture were studied from the determination of the bulk density of the wool,the determination of the optimum amount of asphalt,the method of compaction and the design of grading.At the same time,the difference between the road performance test and the index of the asphalt mixture was evaluated.The results show that:(1)For the typical coarse aggregate graded mix,the difference between bulk density and plastic seal density and surface dry density is the largest.For several mixes,The plastic density has a good correlation with the average of the bulk density and the dry density;(2)The oil-rich coefficient determines that the oil-stone ratio of the mixture has certain limitations,and the determined mixture is not necessarily in the most compact state at this time;(3)The bulk density measured by PCG rotary compaction cannot truly reflect the compaction state of the coarse aggregate graded mix,and the PCG rotary compaction angle is small,which may not be suitable for coarse aggregate breakage compounding.(4)China’s evaluation of the high temperature performance index of asphalt mixture has a certain correlation with the index of the French rim test.Secondly,in the aspect of semi-rigid materials,taking cement stabilized red clay pellets as an example,the effects of different curing conditions on the compressive strength of Chinese and French methods were studied.The size effect of splitting test between China and France in different specimen sizes was studied.The difference of tensile strength between red clay pellets under different load modes in China and France is analyzed.The area of the cement-stabilized laterite pellets in the design curve of the standard strength modulus is also studied.The results show that:(1)At high cement dosage,the French water-immersion method for 4 days is compared with the national standard water immersion for 1d to prolong the hydration reaction time,so that the strength determined by France is greater than the national standard;(2)Under the mechanical state of splitting,the influence of the change of the aspect ratio of the Chinese and French specimens on the strength is not significant;(3)There is a good correlation between the different tensile strengths of the Chinese and French standards;(4)For the red clay pellets,there is a contradiction in determining the material thickness using the standard strength modulus design curve.Finally,based on the established asphalt concrete and semi-rigid material design parameters,the structural design analysis of the four design schemes of the flexible base layer of the TT expressway was carried out using the ALIZE software.The semi-rigid base layer and the composite base layer structure are used to analyze different base structure forms.The results show that compared with the composite base layer and the semi-rigid base structure,the thickness of the pavement structure determined by the GB4-A+35/50+ anti-rutting agent flexible base layer is the thinnest,18 cm.The semi-rigid base asphalt pavement structure has the lowest cost.Through the research of this paper,it can provide a certain reference for the future construction projects of Chinese-funded enterprises. |
PDF Full Text Request