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目前国内外对于沥青混合料的抗水损害有多种评价方法,其中评价沥青与粗集料粘附性的水煮法因操作直观简便而多被采用,但也存在试验条件难以控制、评价结果因人而异的缺陷。本研究通过连续测量沥青和粗集料在水中重量的变化对粘附性进行定量评价以改进目前水煮法主观性大的缺点。文中对4种不同类型石料在基质沥青和添加SEAM改性剂后的情况下的粘附性进行了定量分析和评价。结果表明,采用剥落面积百分率和剥落质量百分率能对沥青与粗集料粘附性进行细化区分,剥落质量百分率指标能更有效、全面、细致地评价沥青与粗集料的粘附性。 相似文献
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Based on Navier-Stokes equation and renormalization group (RNG) onflow model, the 3D symmetrical impinging jet model of laser
cutting is established by adopting a taper nozzle and a convergence nozzle. Numerical simulation of gas flow in laser cutting
is used to investigate the effect of workpiece thickness on flow field of assist gas in cutting slot. The isolines of static
pressure as well as the distributions of static pressure and velocity are analyzed in details with different workpiece thickness,
and the trend of dynamics characteristics of gas jet is shown in the study. For taper nozzles and convergence nozzles, the
dynamic structure of assist gas being close to the lower surface of workpiece is exacerbated while the cutting quality and
cutting efficiency become worse with the increasing of workpiece thickness. The parallel degree between assist gas and the
axis of convergence nozzle is better than that of taper nozzle after the gas goes out of the nozzles. Two typical subsonic
nozzles are designed for the cutting experiment at the end of the paper. 相似文献
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