Advanced Engineering Forum Vol. 5

Abstract: Pavement working state and service life assessment is really meaningful for traffic security, design evaluation and road maintenance. However, this job seems to be a mission impossible, because it is almost incredible to learn how a pavement inside works exactly when the construction is finished. As a result, in this paper, current situation of pavement-design theory and testing methods was summarized, at the same time the concept of Pavement Structural Health Monitoring (PSHM) was introduced, followed by the explanation of the FBG sensing component’s basic theory. Then, an engineering application of utilizing FBG sensors in actual pavement was introduced, the monitoring effect was shown. Conclusion is that PSHM is of great importance and utilizing FBG sensors in PSHM is effective.

Abstract: The types of noise reduction asphalt pavement were summarized such as single layer porous or two-layer porous asphalt pavement, elastic asphalt pavement, optimized surface texture pavement, and universally composable one based on these three types. In Beijing China, it was very drought and short of rainfall, there were large volume of traffic, heavy wheel load and many dirt things on the pavement surface taken by the tires too. So asphalt-rubber pavement was the most common one for noise reduction, which was paved by gap-graded, macrotexture, dense asphalt concrete, belonging to the types of elastic and optimized surface texture noise reduction pavement. And it could reduce tire-pavement noise obviously and had excellent durability, All proved that this types of noise reduction pavement had gone through traffic and climate environment of Beijing well. It had measured tire-pavement noise of asphalt–rubber pavement and stone mustic asphalt pavement in Beijing from 2009 to 2012. This measurement was according to Measurement of close-proximity method，which prepared by international organization for standardization in the year 2000. And the test vehicle was a trailer for measuring tire-pavement noise which met requirements of ISO/CD 11819-2:2000. The factors effected tire-pavement noise spectrum were analysed, such as temperature, speed, age of pavement and so on. It reveals that, The tire-pavement noise sound level could get higher especially higher during the frequency 500Hz~2500Hz in the noise spectrum, while the testing speed increase, or the temperature decrease , or the age of pavement grow. while the frequency lay on the range of higher than 800 Hz, the asphalt–rubber pavement’s noise sound level were lower than the stone mustic asphalt pavement’s one in all situations, and when the temperature decreased from 30°C to 0°C , the low limit frequency decreased from 800Hz to 63 Hz . In order to show the reason , it had tested dynamic modulus and phase angle of the two kinds of pavement materials under different temperature and load frequency with the help of Simple Performance Tester, The result shows that, asphalt-rubber concrete has smaller Phase angle at wide temperature as well as frequency changes, it could be one of the main reasons to explain this phenomenon. It could provide reference for designing, constructing, maintaining and evaluating the noise reduction asphalt pavement.

Abstract: This paper introduces dynamic water effect into the test, develops a laboratory test device for simulating the dynamic water effect on asphalt pavement, and puts forward a test method of dynamic water effect working together with load, water and temperature. Based on this method, the high temperature stability of seven kinds of asphalt mixtures with the factors of asphalt grade, gradation and air voids are studied. The research shows that the effect of dynamic water can take adverse effect for the high temperature stability of asphalt mixture. The effect degree is different under different factors. It is the most disadvantaged when the air voids of the mixture is near 10%, the skeleton structure gradation of mixture is better than the suspended structure at the most disadvantage air voids, and the mixture made of high viscosity asphalt is more affected when the temperature is higher.

Abstract: To improve the cement concrete deformation, small toughness traditional defects, with Adding the rubber grain in the concrete to form the rubber particles concrete; flexural modulus of Rubber particles of concrete and ordinary concrete was comparative studied, two kinds of concrete damping change was analyzed by using the finite element, through three point concrete trabecular bending test, the fatigue properties were comparative researched , the rutting test methods were used in proving the rubber particles of concrete of erosion performance; According to the test made the mechanical parameters of acquired in experiments , the applying the MEPDG 2002 design method, the road surface damage state were forecasted of the two kinds of concrete pavement in the design of the end; Experiment shows that rubber particles cement concrete flexural modulus is reduced by 12% than that of ordinary cement concrete, the damping ratio increased by 30%, the fatigue life have greatly improved, and surface erosion phenomenon did not happen; Theoretical analysis shows that, the rubber cement concrete panel breakage is lower 30% than ordinary concrete, Therefore, the rubber particles concrete pavement can overcome the traditional l defects of cement road and with has excellent road performance.

Abstract: The flexural strength and frost resistance properties of air entrained concrete were tested in this study. Although the flexural strength of concrete does not change largely with increasing of air content, it still has a maximum value with air content of 4%. The test results show that the frost resistance increase with increasing of air content. In air entrained concrete, the total air content is not the only factor that affect the final properties of the concrete, the air void structure parameters, including void size, shape, and distribution, are key factors as well. It was found that the air void structure and the frost resistance properties were influenced by the vibration time largely. The optimized vibration time is 30s.

Abstract: Recent research shows that there is a serious need for accurate methods to evaluate the deformation resistance of asphalt mixtures at high temperatures, especially for stone-skeleton mixtures. To reflect the interlocking angle between coarse aggregates, confining pressure should be considered during testing. The dynamic loading test has been developed for applying different repetitive loads to a limited area of the specimen. This test can measure permanent deformation indices under different loads to evaluate the deformation resistance of asphalt mixtures at high temperatures. The dynamic loading test is conducted on samples with different compaction rates and gradations. Further, the rutting resistance of two types of gradation is compared with a wheel tracking test and a dynamic loading test. The test results indicate that the dynamic loading test can apparently distinguish the influence of gradations on rutting resistance. It is also derived from this test that dense-graded mixtures have higher permanent deformation susceptibility than coarse-graded mixtures, which is consistent with experience in the field and validated by experiments. This test can reflect the entire permanent deformation and separate the compactive deformation and shear flow deformation. Furthermore, this test can simulate heavy and repeated loads to fully exhibit the deformation resistance of asphalt mixtures, especially for coarse-graded mixtures. However, this test is limited by the effects of rigid confinement, which can be improved by changing the confining pressure.

Abstract: A study has been carried out of the glass transition of fifteen asphalt-filler mastics in three different filler types. The dynamic mechanical analysis (DMA) and differential scanning calorimetry (DSC) method were used. The results show that DMA method can measure asphalt Tg of asphalt-filler mastics more accurately than DSC; The glass transition temperature measured by DMA is generally higher by 20~40oC than that measured by DSC; The glass transition temperature of the asphalt-filler mastics increase with the increase of the filler volume fraction, and andesite is the most sensitive; When the volume fraction of filler is greater than 0.5, the enhance capability of glass transition temperature of asphalt-filler mastics is in the order of andesite > granite > limestone; while the volume fraction of filler is smaller than 0.2, the enhance capability is in the order of granite > limestone > andesite.

Abstract: The built-in temperature gradient of concrete pavement formed during hardening period caused by various construction conditions will permanently exist in the pavement, which will have significant influence on the service behavior of concrete pavement. However, it’s still not involved in the current Specifications of Cement Concrete Pavement Design for Highway in China. In this paper, a user subroutine based on the ABAQUS code was developed to simulate the effects of weather condition, paving time, curing method, raw material temperature on built-in temperature gradient. The analyses indicate that these factors always produce obvious positive gradient in the slab and the influences of the first three aspects are obvious and the paving temperature of mixture has limited effect on the increasing of the final set temperature gradient. Furthermore, built-in temperature gradient is proposed as an index to evaluate the influences of various construction factors and optimize construction measures.