Study On The Black Underlayer Of Cement Concrete Pavement Under Heavy-traffic Conditions

Currently, under the situation of increasing transportation needs, the functionaland structural damage of cement concrete pavement with semi-rigid base seriouslyaffect the service levels and life of highway. And the vehicle overloading are commonoccurrences. Especially under the heavy-traffic conditions of large industrial areas,the base of concrete pavement could be eroded to be void, which leads to the concreteslab uniformly support losses. What is more, it caused pumping, slab breaking andother damage phenomena. The early damages of pavement structure seriously affectroad capacity, traffic safety and economic benefits. Therefore, a treatment measure ofsetting a black underlayer based on improving working conditions of interlayer ofpavement stuctures was proposed. It would alleviate or even eliminate erosiondamage and improve the stress state of the pavement structure to improve theperformance and prolong the fatigue life of cement conceret pavement structures.Rely on the project of Zhunxing heavy-load highway in Inner Mongolia，theresearch were mainly did from following aspects which includes:(1) Analyzing thecement concrete pavement distruction mechanism and its influence factors throughinvestigating the traffic characteristics of Zhunxing highway, establishing theABAQUS finite element models of pavement structures to determine the heavy-loadeffects on the structures mechanic performance with erosion or not and with a blackunderlyer placing between cement slab and semi-rigid base.(2) Analyzing the blackunderlayer material performance of the resistance to water damage, studying theinfluence factors of water permeability resistance,setting up the seepage calculationmodel, calculating the black layer material sealing performance under differentconditions, studying internal pore water pressure condition of the black underlayerand material erosion damage theory, analyzing various factors of the black underlayerunder the conditions of anti-erosion performance, and the hydrodynamic pressurecondition beneath the slab and the anti-pumping performance.(3) Setting up blackunderlayer fatigue life forecast model, calculating fatigue life of different thickness and modulus models and studying the overall anti-fatigue performance of pavementstructure with black underlayer.(4) Putting forward the cold mix cold coat blackunderlayer material’s quality and technical indicators and its construction qualitycontrol index, and the acceptance standard as well to provide practical significance forthe cement concrete pavement engineering construction.