摘要: In order to establish the mixture design method for warm mix asphalt (WMA), Marshall test was conducted under variable temperatures and compaction times to prepare AC-13C WMA specimens, and the volume characteristics of WMA specimens were researched. Analysis result indicates that the air void volume (VV) and the percent voids in mineral aggregate (VMA) increase with the decrease of compaction temperatures and compaction times, but the percent voids in mineral aggregate that are filled with asphalt (VFA) decrease. Compared with hot mix asphalt (HMA), the asphalt content absorbed by aggregates, the effective asphalt content (mass fraction) and the thickness of asphalt film in WMA differ a little, and the optimum asphalt content of AC-13C WMA is 4.7%. According to the volume characteristics, the compaction temperatures of WMAs are determined, and the compaction temperatures of WMAs with matrix asphalt and SBS modified asphalt decrease by about 10 ℃-20 ℃ and 10 ℃ respectively. WMA compactibility is better, and the compaction times of WMAs with matrix asphalt and SBS modified asphalt decrease by about 20% and 10% respectively.更多>
摘要: The load-deflection curves of RC beam strengthened with high-strength steel wire mesh and polymer mortar overlay were analyzed, and the bond mechanism between concrete surface and polymer mortar was studied. The overall flexural behaviour of strengthened beam could be divided into precracking stage, cracking stage and failing stage, and an analysis model of section moment and mid-span deflection for RC beam was developed based on plane assumption. The overall flexural behaviour of strengthened beam subjected to concentrated load was analyzed by using transformed section method, and the model was verified by using the test data of 10 strengthened beams. Analysis result shows that the average ratios between the test values and computation values of yielding moment and ultimate moment of beam section are 1.027 and 1.094 respectively, the average ratios between the test values and computation values of yielding mid-span deflection and ultimate mid-span deflection are 1.286 and 0.918 respectively, so the model is feasible.更多>