Road Performance Study On The High Performance Pavement Concrete In Seasonal Frozen Region

As a main type of pavement structure, cement concrete pavement accounts for a considerable proportion in our country. Up to now cement concrete pavement accounts for about 50% of the total mileage all over the whole country, and 60% in Jilin province. However, under the cooperative effect of raw material, construction control, environment etc., various diseases occurred in the cement pavement. Especially the degradation of concrete durability was extremely serious, and it brought great difficulties to the later maintenance. In order to solve these problems, and show the virtues of cement pavement such as high performance, anti-rutting and long working life etc., it is tremendously significant to carry out the study on high performance pavement concrete combining with the characteristic of seasonal frozen region.This paper was supported by the key project scientific research of Jilin province. It put forward the technical method for the first time by adding mineral ultra-fine powder and superplasticizer of air entraining agent to realize the high performance pavement concrete system, and made a comprehensive study on various road performances of high performance pavement concrete(HPPC). The paper firstly analyzed the disease mechanism character of cement concrete pavement in Jilin province, and processed physico-chemical properties experiment of bioactive admixture in this region. By making a bioactive comparison towards 5 ultra-fine powders and testing research to the ultra-fine powder, cement and admixture, the material components and technical index suitable for HPPC in the seasonal frozen region was presented.The match ratio research of high performance pavement concrete based on durability was put forward. The coarse aggregate gradation and optimal sand ratio was selected by"maximum density test method". The study optimized the concrete match ratio through orthogonal design test and found out the prominent influencing factors. Bring forward durability as a main target (frost resistance, resistance to hydraulic pressure and strength), the match ratio design method that suitable for HPPC in the seasonal frozen region was presented. The optimal admixture amount of mineral ultra-fine powder in the HPPC, proportion and total amount of binder material were confirmed by mechanical properties research (compressive strength, rupture strength, elastic modulus), and took a analysis on the influencing factors of each index.This paper made a comprehensively and systematically study on wear resistance, resistance to hydraulic pressure, frost resistance, shrinkage performance and anti-fatigue character and so on. In accordance with the climate character of seasonal frozen region, accelerating freezing and thawing damage test by coupling with frost and salt was designed. It shows that frost and salt resistance, resistance to hydraulic pressure of HPPC overrun the common cement by a large margin. In addition, the proportion to mixture of powdered zeolite powder and fly ash must be appropriate, or else it will reduce the wear resistance and shrinkage property of concrete.The study also comprehensively and thoroughly analyzed the micro-mechanism and structure feature of strength and durability forming of HPPC by SEM, mercury-infection, XRDA and DTA test. The results indicated that the content of C-S-H in HPPC was far higher than base concrete. Its porosity reduced significantly, and void structure and void gradation were improved greatly. Cementitious pore accounted for 70% of total pores in concrete. Therefore it had a better frost resistance and anti-permeability.The study constructed the test road of HPPC. The test proved that HPPC had a virtue of feasible construction control technology, easy control to work, good pavement smoothness, and few cracks and so on. Later bore specimen test indicateed that the flexural strength, anti-chloride ion penetration performance, shape and quantity of inner air void was superior to contrast road.At last by analyzing the comprehensive performance and the cost performance of HPPC, four indexes frost resistance, resistance to hydraulic pressure, mechanical property, and fatigue life were prominently higher than base concrete. Its comprehensive performance was 1.65 times of base concrete, and its cost performance was 1.5 times of base concrete. HPPC not only has a perfect road performance but also has a better economic and social effect.Thus it can be seen, the study production play a positive role on improving construction quality of cement concrete pavement in the seasonal frozen region, making a better utilization of local resources, improving design and construction technology of cement concrete pavement and promoting the development of cement pavement in this region.