Influencing Factors And Compaction Quality Evaluation Of Compaction Test With Pavement Quality Indicator

Most of China's high-grade highways choose to paving asphalt pavements.However,within 2 to 3 years after completion and completion,some pavements have early diseases such as shifts and cracks.Some studies have found that due to the uneven quality of the laminate below,there is a hidden danger of insufficient compaction,which leads to the early disease of asphalt pavement.The core drilling method is an after-the-fact detection behavior,which cannot be detected in real time and adjust the construction plan in time.The Pavement Quality Indicator provides instant detection of asphalt pavement density.The research literature shows that the detection accuracy of the coarse-grain asphalt concrete of the previous generation Pavement Quality Indicator PQI-301 is not high,which hinders its application to the underlying layer inspection.Therefore,based on the new generation of Pavement Quality Indicator PQI-380,this paper studies the influencing factors of the test accuracy of the underlying coarse-grain asphalt concrete.Four coarse-grained asphalt concrete grades commonly used in the lower layer were selected,and the structural depth values of the asphalt concrete specimens were obtained by a laser texture meter.The density value of the test piece was measured using a Pavement Quality Indicator,and the influence of the structural depth change on the test accuracy was analyzed by comparing with the core sample density value obtained by the core sampling.The indoor test simulates the temperature and humidity environment of the field test,and analyzes the influence of temperature and humidity changes on the detection accuracy.To study the factors affecting the compaction quality of coarse-grained asphalt concrete,the ATB-25 grade was selected as the coarse-grained asphalt concrete representative gradation,and the oil-stone ratio,forming temperature,aggregate segregation and rolling pass were selected as four influencing factors.Analyze the effect of changes in factors on concrete density.Using grey correlation theory and multi-factor analysis of variance,it is found that the separation of coarse and fine aggregates has the most significant effect on concrete density.Considering the rapid paving of urban roads,the test section is not pre-paved,that is,the coreless density meter cannot be calibrated through the test section core,and the difference between the Marshall test piece density value and the uncalibrated Pavement Quality Indicator test value is proposed.To evaluate the quality of pavement compaction.Analyze the inadequacies of the existing temperature segregation standards,set different molding temperatures,and study the molding temperature limit of four kinds of coarse-grained asphalt concrete without temperature separation.The recommended minimum molding temperature is 105°C.Pavement Quality Indicator was used to test the compaction quality of the lower layer ATB-25 asphalt concrete of Jitong Expressway.The test pile interval was K60+030~K65+180.The density values of the pavement without segregation,coarse segregation and fine segregation were measured.Compared with the core sample density obtained by the core sampling,the PQI-380 was tested to determine whether the test accuracy of the underlying layer ATB-25 asphalt concrete meets the requirements.The paving sections of RK62+884 and RK63+135 were selected to test the degree of compaction of each point of the section along with the number of rolling passes.The ASTM comparison test method was introduced,and the RK63+240~RK63+290 section was continuously tested in full width to evaluate the uniformity of construction quality.