| Summary: | 碩士 === 國立中央大學 === 土木工程研究所 === 87 === Under the subtropical climate-high temperature, humid and rainy-in Taiwan , We had poor drainage system of highways when it rains. It is easy to find accumulated water on the surface and it results in a lot of water vapors which spray out when cars run by. Those spray of vapors make poor visibility that affects driving safety, and the existence of water membrane decreases the friction on the road surface as well as durability of the paving asphalt.
The above phenomena is found connecting with the Open-Graded Friction Course(OGFC) , the property of aggregate , the property of asphalt, oil-content , quantity of Tack Coat and construction factors . By now the surface of highways in Taiwan is paved with 1.5 cm Open-Graded Friction Course, but it doesn’t seem to have much effect on that . To improve what we mentioned above , this research is to find out the best composition of the Open-Graded Friction Course . It is based upon the grade (nominal size 3/8”) adopted by National Expressway Engineering Bureau , and we use AC-20 asphalt or a better one, the lower flat and elongated rate of crushed stones which are selected by centrifugal force with the lime as anti-stripping agent.
The design of Open-Graded Friction Course in this research includes the best match between the oil-content and mixed temperature . We use testing objects produced by SGC under a series of experiments of letting water-through , being worn out , peeled off , anti-slippery and ruts , and then engage in the mechanics experiment such as the Resilient Modulus , Indirect Tension and Creep . At last, we evaluate the results by simulating the durability and anti-aging of Open-Graded Friction Course in ultraviolet-rays dryer .
After analyzing the results of all experiments, it shows that the Open-Graded Friction Course composed with high quality asphalt , low flat and elongated rate of crushed stones which are selected by centrifugal force added with lime or contented with more CaO of BOF slag is much better than the traditional one in results that declare to improve efficiently the situation we have in highways.
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