Study on grading envelope of AC-16 asphalt mixture based on rutting resistance performance
In this paper, the coarse aggregate packing density tests are studied on different proportion the various particle sizes over 4.75mm, and the demarcation point between coarse and fine aggregate of AC-16 asphalt mixture is 4.75mm, the optimum grading of coarse aggregate is determined by the minimum voids in mineral aggregate. Freeze-Thaw Split and Rutting are tested on 9 kinds of grading AC-16 asphalt mixture with different size and proportion fine aggregate. The results show that the percent passing 4.75mm sieve has affected significantly on the high-temperature rutting resistance and water stability of the asphalt mixture. Based on laboratory test results and grading application experience, it is proposed that the engineering design grading envelope of AC-16 asphalt mixture adapted to the summer hot climates characteristics, which improved the rutting resistance capability of asphalt pavement in hot areas during summer.
Experimental Investigation of Improving Anti-stripping Performance of Asphalt Mixture
Long term immersing Marshall test and frozen-thaw cycle test were used to investigate the anti-stripping performance of andesite asphalt mixture using cement and anti-stripping agent.It can be concluded from the experimental results that both cement and anti-stripping agent show improvement on moisture stability of asphalt concrete.The anti-stripping performance is significant improved by using cement and anti-stripping agent together.
The distribution of 54-Mn in the enamel and dentine of the rat incisor.
Abstract The distribution of 54 Mn was studied in the lower incisors of rats. Autoradiograms show 54 Mn to be present in the enamel and dentine 5, 10 and 15 days after its administration. In the dentine, the radioisotope is first localized in a zone near to and encircling the pulp and later becomes more diffuse. Pre-existing as well as the newly formed enamel incorporates the isotope. In both enamel and dentine 54 Mn appears to be principally associated with the inorganic portion.