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In order to perform three-dimensional digital sieving based on X-ray computed tomography images, the definition of digital sieve size (DSS) was proposed, which was defined as the minimum length of the minimum bounding squares of all possible orthographic projections of an aggregate. The corresponding program was developed to reconstruct aggregate structure and to obtain DSS. Laboratory experiments consisting of epoxy-filled aggregate specimens were conducted to investigate the difference between mechanical sieve analysis and the digital sieving technique. It was suggested that concave surface of aggregate was the possible reason for the disparity between DSS and mechanical sieve size. A comparison between DSS and equivalent diameter was also performed. Moreover, the digital sieving technique was adopted to evaluate the gradation of stone mastic asphalt mixtures. The results showed that the closest proximity of the laboratory gradation curve was achieved by calibrated DSS, among gradation curves based on calibrated DSS, un-calibrated DSS and equivalent diameter.
Chichun Hu; Jiexian Ma; M. Emin Kutay. Three Dimensional Digital Sieving of Asphalt Mixture Based on X-ray Computed Tomography. Applied Sciences 2017, 7, 734 .
AMA StyleChichun Hu, Jiexian Ma, M. Emin Kutay. Three Dimensional Digital Sieving of Asphalt Mixture Based on X-ray Computed Tomography. Applied Sciences. 2017; 7 (7):734.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; M. Emin Kutay. 2017. "Three Dimensional Digital Sieving of Asphalt Mixture Based on X-ray Computed Tomography." Applied Sciences 7, no. 7: 734.
In this study, to overcome the high cost of accelerated loading test, a small-scale laboratory experiments were developed and conducted toward the potential dowel bar alternatives. Similarity theory and Accelerated Pavement Analyzer were used to evaluate dowel bars with different materials and cross-sections. The test results showed that larger FRP dowel is required to produce the same load transfer efficiency and differential deflection which would be produced with given size of round steel dowel. Moreover, steel dowel with large diameter can effectively improve the ability of joints to transfer vertical shear forces and reduce the internal stress, thereby extending the service life of dowel load transfer system.
Chichun Hu; Jiexian Ma; Jianying Zhao. Evaluation of Dowel Bar Alternatives Based on Similarity Model Test. DEStech Transactions on Engineering and Technology Research 2017, 1 .
AMA StyleChichun Hu, Jiexian Ma, Jianying Zhao. Evaluation of Dowel Bar Alternatives Based on Similarity Model Test. DEStech Transactions on Engineering and Technology Research. 2017; (ictim):1.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; Jianying Zhao. 2017. "Evaluation of Dowel Bar Alternatives Based on Similarity Model Test." DEStech Transactions on Engineering and Technology Research , no. ictim: 1.
In this study, a small-scaled accelerated loading test based on similarity theory and Accelerated Pavement Analyzer was developed to evaluate dowel bars with different materials and cross-sections. Jointed concrete specimen consisting of one dowel was designed as scaled model for the test, and each specimen was subjected to 864 thousand loading cycles. Deflections between jointed slabs were measured with dial indicators, and strains of the dowel bars were monitored with strain gauges. The load transfer efficiency, differential deflection, and dowel-concrete bearing stress for each case were calculated from these measurements. The test results indicated that the effect of the dowel modulus on load transfer efficiency can be characterized based on the similarity model test developed in the study. Moreover, round steel dowel was found to have similar performance to larger FRP dowel, and elliptical dowel can be preferentially considered in practice.
Chichun Hu; Jiexian Ma; Jianying Zhao; Zhen Leng; Denis Jelagin. Experimental Study of Dowel Bar Alternatives Based on Similarity Model Test. Advances in Materials Science and Engineering 2017, 2017, 1 -9.
AMA StyleChichun Hu, Jiexian Ma, Jianying Zhao, Zhen Leng, Denis Jelagin. Experimental Study of Dowel Bar Alternatives Based on Similarity Model Test. Advances in Materials Science and Engineering. 2017; 2017 ():1-9.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; Jianying Zhao; Zhen Leng; Denis Jelagin. 2017. "Experimental Study of Dowel Bar Alternatives Based on Similarity Model Test." Advances in Materials Science and Engineering 2017, no. : 1-9.
In order to compute the optimal dowel length in cement concrete pavement, semi-infinite beam on elastic foundation was deduced and modified for the analysis of dowel bars. The dowel deflection, bending moment and shearing were analyzed for dowel bars under the traffic loading, dowel length based on the second inflexion distance was computed and a relationship between dowel length and dowel diameter was established. The theoretical analysis found that the dowel length in Chinese specification is conservative. A finite element model was also established to simulate the dowel load system. Based on the result of maximum value and variation tendency of mises stress for different dowel diameters and dowel lengths, it is feasible to shorten dowel length specified in JTG D40-2002 by 50%. However, considering the construction tolerances in the making and sawing of joints in new pavement construction, which might add 50–150 mm to the required overall dowel length, it’s more appropriate to reduce the dowel length by 20% in practice.
Chichun Hu; Jiexian Ma; Yuan Yu; Yi Luo. Optimal design on dowel length for cement concrete pavement. International Journal of Pavement Research and Technology 2016, 9, 414 -423.
AMA StyleChichun Hu, Jiexian Ma, Yuan Yu, Yi Luo. Optimal design on dowel length for cement concrete pavement. International Journal of Pavement Research and Technology. 2016; 9 (6):414-423.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; Yuan Yu; Yi Luo. 2016. "Optimal design on dowel length for cement concrete pavement." International Journal of Pavement Research and Technology 9, no. 6: 414-423.
In the allowable range of bearing capacity of dowel bar, shortening the dowel length or increasing the dowel spacing can effectively reduce the initial construction cost of jointed plain concrete pavement. In order to calculate the optimal dowel length and spacing in cement concrete pavement, Timoshenko’s model of a beam resting uniformly on an elastic foundation was modified for the analysis of dowel bars. Based on the model, the deflection, bending moment, and shearing of dowel bars under the traffic loading were analyzed, and dowel length was computed. The relationships between the dowel spacing and effective number, mechanics of dowel bar were also established. The results showed that the dowel length suggested in the current specification can be reduced by 20% and the dowel spacing can be increased by 30% given the same diameter.
Chichun Hu; Jiexian Ma; Yuan Yu; Yi Luo; Sayvichit Phimmatat. Study on Dowel Bar Length and Spacing Based on Theoretical Computation. Geo-China 2016 2016, 45 -52.
AMA StyleChichun Hu, Jiexian Ma, Yuan Yu, Yi Luo, Sayvichit Phimmatat. Study on Dowel Bar Length and Spacing Based on Theoretical Computation. Geo-China 2016. 2016; ():45-52.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; Yuan Yu; Yi Luo; Sayvichit Phimmatat. 2016. "Study on Dowel Bar Length and Spacing Based on Theoretical Computation." Geo-China 2016 , no. : 45-52.
Many researches have focused on the application of titanium dioxide (TiO2) to the asphalt pavement to achieve the function of degrading automobile exhaust. Due to the good compatibility, high fluidity and strong bonding strength of waterborne epoxy resin, it is selected as the carrier of nano-titanium dioxide (TiO2). Therefore, in this study the feasibility of TiO2 waterborne epoxy resin as fog seal and exhaust degradation material was evaluated in asphalt pavement. To achieve this goal, laboratory photocatalytic performance, mechanical property and skid resistance tests were performed on waterborne epoxy resin with different content of nano-TiO2. The results showed that nano-TiO2 waterborne epoxy resin not only decomposes NO pollutant efficiently, but also maintains the skid resistance of the pavement.
Chichun Hu; Jiexian Ma; Hong Jiang; Jianying Zhao; Zhiwu Chen; Dharamveer Singh; Jan Valentin; Zhen (Leo) Liu. Study on Exhaust Degradation Material for Asphalt Pavement. Geo-China 2016 2016, 38 -44.
AMA StyleChichun Hu, Jiexian Ma, Hong Jiang, Jianying Zhao, Zhiwu Chen, Dharamveer Singh, Jan Valentin, Zhen (Leo) Liu. Study on Exhaust Degradation Material for Asphalt Pavement. Geo-China 2016. 2016; ():38-44.
Chicago/Turabian StyleChichun Hu; Jiexian Ma; Hong Jiang; Jianying Zhao; Zhiwu Chen; Dharamveer Singh; Jan Valentin; Zhen (Leo) Liu. 2016. "Study on Exhaust Degradation Material for Asphalt Pavement." Geo-China 2016 , no. : 38-44.