土工合成材料防治沥青路面裂缝的作用和施工技术

一、前言 沥青路面裂缝产生原因是多方面的,既有地基的原因,也有设计和施工的缺陷与不足,还有温度、环境暴露和老化等原因,另外还有重复荷载作用下的疲劳裂缝等。 当前通常使用两类方法来防治裂缝,第一类方法注重阻止或减少施工初期裂缝的形成。

焦炭粉造粒新工艺

介绍了采用压制成型的方法,以煤沥青为主要粘合剂,使黄磷生产中被废弃的焦炭粉成球并炭化后回收利用,所制得的焦炭球的物理、化学性质与原始焦炭基本相同. 该工艺已在实际生产中应用.

知识园地

石油沥青专利1 专利名称:一种用于聚合物改性沥青的稳定剂组合物及制备方法专利申请号:02140429.1公开号:1408750 申请人:中国石油化工股份有限公司茂名分公司研究院一种用于聚合物改性沥青的稳定剂组合物及制备方法。本发明提供了一种用于聚合物改性沥青的稳定剂组合物。稳定剂主要由硫化交联剂、交联促进剂、分散剂等复配而成。其制备方法是在混合器中加入硫化交联剂10%-90%(质量分数);交联促进剂10%-90%(质量分数);分散剂10%-90%(质量分数);充分搅拌混合研磨,温度10-80℃,时间10-60 min,得到的产品为粒径小于200目的聚合物改性沥青稳定剂组合物。

Evaluation of reclaimed asphalt pavement binder stiffness without extraction and recovery

A new testing procedure to estimate the low-temperature stiffness of the reclaimed asphalt pavement （RAP） binder was developed. In the testing procedure, the SuperpaveTM Bending Beam Rheometer （BBR） with special modifications and binder blending charts by Asphalt Institute were utilized. Modifications involved the development of a new kind of sample mold and different testing parameters were made to BBR testing procedure to capture the theological properties of bitumen mortars produced by mixing fresh binder with fine RAP materials or RAP aggregate. The stiffness relationship between binder and bitumen mortar was established based on the BBR test results. The blended binder stiffness in bitumen RAP mortar was estimated from the RAP mortar stiffness based on the binder-mortar relationship. And finally, the RAP binder stiffness was estimated from the blended binder and fresh binder stiffness based on the blending charts by Asphalt Institute. The results indicate that the new procedure can capture the rheological properties of bitumen mortar and can be used to estimate the low temperature stiffness of RAP binder without binder extraction and/or any chemical treatments.

Viscoelastic Characteristics of Asphalt Binders at Softening Point Temperature

In this paper, in order to investigate the viscoelasticity of asphalt binder at the softening point temperature, more than 30 different asphalt binders were selected and tested by dynamic rheological scan method using a dynamic shear rheometer(DSR). The softening points and the rheological parameters of the asphalt samples were measured and analyzed. The results indicated that at the softening point temperature the neat asphalt and the SBS modified asphalt showed two different rheological states. The neat asphalt binders had a majority of viscous components in viscoelastic composition, with the phase angles being mostly higher than 80 o. The SBS modified binders had lower phase angles, with their elasticity still retained. Meanwhile, the Shapiro-Wilk normality test showed that at a confidence level of 0.05, at whatever aging state, the neat asphalt had a stable complex modulus corresponding to the softening point, which was 13.034 kPa at a standard deviation of 2.105 kPa under the same test condition. The softening point of neat asphalt binder can be calculated via the equivalent modulus rule. It is found out that there is a good relationship between the calculated and the measured softening points. And it is suggested that more data are needed to validate this finding.

Waste Tire Rubber Particles using to Improve the Properties of Local Asphalt Concrete

The research considered urgent ecological reasons linked to environment such as worn tires, the waste tire rubber＇s powder was collected from the tire cars repair shops （passed from the sieve No 18 μm）, and used to improve the asphalt concrete properties. Raw materials used were prepared and tested. Varies of asphalt concrete mixtures were prepared with different ratios of bitumen （5, 5.5, 6, 6.5, 7% % of concrete weight）. The Marshall mix design method was used to determine optimum conditions for bitumen in asphalt concrete with specific weight, stability and flow Test, the optimum amount of bitumen was 6.1% of whole asphalt concrete. The different percentages of waste tire rubber powder （0.0, 0.05, 0.10, 0.15% of bitumen weight） were added in optimum bitumen of asphalt concretes, then specific weight and Marshall test were evaluated. These asphalt-rubber mixtures were found to act quite differently from traditional, unmodified asphalt mixtures. However, these results indicate that improved pavement performance can be achieved with asphalt-rubber binder.

Measured and Predicted Aging Properties of Arizona Asphalt Binders

The Arizona Department of Transportation （ADOT） in the USA conducted a series of asphalt aging related research and special studies between the 1970s and 1990s. The studies covered over 157 test sections representing both neat （virgin） asphalt and crumb rubber modified （asphalt-rubber） binders. The data comprised of a wide range of penetration, viscosity, and Performance Grade （PG） parameters, at original and aged conditions. In the late 1990s, asphalt PG complex shear modulus （G＊）, and phase angle （5） data were collected. The main purpose of this paper was to use the assembled database of the field core-aged asphalt test data and compare the test results to the American Association of State Highway and Transportation Officials approved Mechanistic-Empirical Pavement Design Guide （MEPDG） predictive modeled asphalt properties such as penetration and viscosity, G＊, and 5. Furthermore, G＊ and laboratory measurements on neat and asphalt-rubber binders extracted from the field cores of the pavement sections aged ten or more years were compared to the pressure aging vessel PG G＊ and ~. values. It was observed that the MEPDG predicted asphalt binder properties were rational for originally （tank） sampled binders, but fairly correlated for the aged binders. Additionally, penetration and viscosity aging indices representing over 20 years of field aged sections were established for a wide variety of asphalt binder grades. Overall, the relationships for aging indices were meaningful and rational. Results of this research indicated the degree of difficulty in predicting asphalt binder properties for pavements with ten or more years of field aging. The findings from this research study are envisioned to be of substantial value in future asphalt binder aging studies.