Effects Analysis Of CTE On The PCC Pavement Panel Design

Because of stiffness, load capacity and strong diffusion, high strength, longfatigue life, flatness decay slowly to maintain high flatness long time, etc., PCCpavement is one of the main forms of high-grade road construction, which is widelyused, especially in low-grade roads, mining roads and airport runways. By the end of2012, PCC pavement of highways accounted for39%of total length in China. ButPCC surface laminate edge premature destruction, surface cracking, transverse jointfaulting and other diseases have plagued road engineering. The study finds that: thethermal expansion coefficient of PCC has a certain effect on the structural design ofPCC pavement. However, most current research is the analysis of factors affecting thethermal expansion coefficient values, and the coefficient of thermal expansion studyhow they affect the structure of PCC pavement design is rarely. What is analyzed andexplored in this paper focused on the impact of thermal expansion coefficient on PCCpavement structure design.In order to research the effects of coefficient of thermal expansion on the PCCpavement design, some efforts have been done. In the first place, analyzing theinfluence of coefficient of thermal expansion on the design thickness of surface layer,according to the PCC pavement design standard in our country and the United Statesmechanistic-empirical design method, corresponding PCC pavement design softwaresare used. There are significant differences in the influence of coefficient of thermalexpansion on pavement thickness design because of the different design standards. Inour country, there are effects of coefficient of thermal expansion only on temperaturestress, but in the United States, mechanistic-empirical design method more concernedabout the effects of coefficient of thermal expansion on the joint load transfer and thewarping of slab corner. In the second place, according to the PCC pavement designstandard in our country and finite element numerical simulation software, theinfluence of coefficient of thermal expansion on the temperature stress is analyzed,and the mechanistic-empirical design method is used to analyses the influence of coefficient of thermal expansion on transverse slab cracking and transverse jointfaulting. And joint load transfer prediction model and the new idea about fatiguestress of PCC pavement calculates is proposed.The conclusion is drawn. The first, there is a significant impact of the thermalexpansion coefficient on PCC pavement surface slab fatigue temperature stress,which will increase more than10%, even up to59%when the thermal expansioncoefficient for each additional1×10-6/℃. Second, there are a great effects ofcoefficient of thermal expansion on both transverse slab cracking and transverse jointfaulting, which transverse slab cracking rate increase by400%and transverse jointfaulting rate increase of65%when the thermal expansion coefficient for eachadditional1×10-6/℃. Third, the coefficient of thermal expansion has a great impacton the designing of pavement thickness especially on the joint load transfer and thewarping of slab corner.Therefore, the impact of the thermal expansion coefficient on fatiguetemperature stress, the joint load transfer and the warping of slab corner should befully considered, and load transfer joints prediction model and fatigue thermal stresscalculation methods should be optimized, and the test procedures of coefficient ofthermal expansion of cement concrete should be established, which can effectivelyreduce the PCC pavement diseases and provide a reference for further optimization ofPCC pavement.