Study On The Cement Filler To The Long-term Water Stability Of Asphalt Concrete Impact

As China’s water conservancy development and construction of asphalt concrete core wall dam construction projects increasing. In recent years, suitable dam topographic and geological conditions getting worse, some of the suitable construction of asphalt concrete dam areas not suitable alkaline mineral aggregate, while in Northwest China, especially Xinjiang, natural gravel with a wide distribution, local materials, etc., asphalt concrete core wall full use of natural gravel aggregate water conservancy sector more and more attention. More compared to asphalt concrete asphalt content asphalt concrete core wall dam, the amount of filler is also higher porosity generally less than 3%. Water molecules in a short time is difficult to enter the interior of asphalt concrete, and water damage manifested behavior is not easy, according to the conventional test method for asphalt concrete water stability can easily achieve regulatory requirements, and sometimes even water stable coefficient larger than 1.0. Thus, when performing asphalt concrete core wall of water stability factor determined by asphalt concrete testing procedures approach has become inadequate. By Marshall immersion test, the freeze-thaw splitting test, appropriate to extend the soaking water stability test of time and the increase of water temperature and prolong the stability of the water soaking time Stability Test of Cement packing on hydraulic asphalt concrete. The main results are as follows:(1) Water into the interior of the test speed and extent of porosity size. By controlling compaction times get different porosity of asphalt concrete specimens were immersion Marshall test and extend the number of freeze-thaw thaw splitting test. When the cement as filler, residual stability of flooding increases the porosity decreases; freeze-thaw splitting strength with the change of porosity is not obvious, with the increase in the number of freeze-thaw slightly lower. When powder is as filler, freeze-thaw splitting strength with increasing porosity decreased slightly with the increase of the number of freeze-thaw slightly. Asphalt cements filler freeze-thaw splitting strength ratio TSR relatively large powder filler.(2) powder as filler in cement and asphalt concrete specimens prepared by an appropriate extension of water stability test results comparing soaking time: cement test piece filler hydration occurs when flooding, the solution pH value increased 8.7 to 12.12, and the aqueous stability factor is increasing; and as filler in powder specimen solution pH value unchanged during flooding, and water stability coefficient decreasing. As can be seen, the cement can effectively improve the performance and stability of asphalt concrete core wall of water.(3) respectively, to 12% of cement, 6% and 6% of cement powder and 12% filler powder is prepared specimen by raising the immersion temperature under condition of 80 to l℃ ong term stability test water. 12% of cement, 6% and 6% of cement powder as filler for asphalt stability coefficient increases with time after immersion in water first increases and then decreases, and after soaking 375 h, the largest water stability factor in the soaking water to 1500 h after stability factor 0.94 and 0.95, and still meet regulatory requirements; and 12% for the powder filler for asphalt stability coefficient with immersion time continued to decline, to 75 h after water immersion stability factor of 0.88, it has not satisfied the specification requirements. Cement filler can effectively improve the long-term water stability of asphalt concrete core wall.