织物加筋沥青面层的研究

研究生：黄岩

指导教师：郭忠印教授

一九九九年一月

摘要

在对国内外土工织物性能、测试方法和指标、沥青面层常用土工织物种类及其使用效果广泛调研的基础上，选用两种具有典型力学特性的土工织物（抗拉强度小、延伸率大的土工布和抗拉强度大、延伸率小的玻璃纤维网格）作为加筋材料，与沥青混凝土复合成织物加筋沥青面层。对其进行了综合性室内试验研究（土工织物性能测试、织物加筋沥青混凝土小梁抗弯拉性能测试、沥青混凝土半中梁疲劳试验和足尺试验）、室外试验路验证。结合理论分析，全面系统地评价了不同织物加筋沥青面层的适用场合及使用效果，提出了织物加筋沥青面层应用于不同路面结构时，对织物选型和铺设方式的技术要求。
     论文回顾了以往旧水泥混凝土面层上沥青加铺层内反射裂缝产生的原因、分析方法及分析结果。依据室内、外试验测试结果，针对理论分析中的不足和织物加筋沥青面层自身的特点，在室内疲劳试验的基础上，建立了梁顶弯沉、裂缝扩展长度，梁底裂缝宽度之间的关系；此关系可以用来评价织物加筋沥青面层的使用性能，进而建立应用于旧水泥混凝土面板上的织物加筋沥青面层设计方法。
     通过净现值法分析了织物加筋沥青面层应用的经济效益。分析结果表明，虽然织物加筋沥青面层一次性投资比普通沥青混凝土（加铺）层大，但是却能大量节省长期的养护费用。

论文还初步提出了应用于己有水泥混凝土路面上的织物加筋沥青加铺层设计、施工方法。

关键词：织物加筋沥青面层，理论分析，反射裂缝，土工织物选型，使用性能评价，设计施工方法，室内试验，经济效益

ABSTRACT

After  extensive investigations on the properties of geosynthetic, test methods, and  use performances, two kinds of typical geosynthetic with different mechanical  properties are chosen in this research paper. One is geotextile which has low  tensile strength and high enlongation, while the other is glass grid which  has high tensile strength and low enlongation. They were used as reinforcing  materials in asphalt concrete to produce geosynthetic reinforced asphalt  concrete courses (GRACC).

    The tensile properties of the geotextiles, the flexural properties and the  fatigue properties of geosynthetic reinforced asphalt concrete were tested in  laboratory. Relations between the deflection at the top of beam，the length of crack and the  width at the bottom of beam were concluded through doing fatigue tests．The full-scale test of GRACC  was carried out．The  curves which includes the deflection at the top of GRACC' surface and the  strain at the bottom of the GRACC changing with loading times have been  drawn. Test roads using GRACC were constructed and the performance was  surveyed. Theoretical analyses were done to evaluate the performances and  reinforced effectiveness of different GRACC. Then, some advises were given on  the choice of geosynthetic types and technical requirements on the paving  period of GRACC.

    This paper also reviewed the theoretical analysis methods of reflective  cracks emerged on the asphalt overlays over the existing cement concrete  pavements. It is proposed that the design method of GRACC can be developed  regarding the crack propagation rate under traffic load. The economic  benefits of GRACC were estimated using the net-current-value method. The  analysis results show that the GRACC can save long term mass maintenance  costs, though its initial invest is more than that of conventional asphalt  concrete course.

    The design and construction method of the GRACC which is used overlay on the  existing cement concrete pavement were preliminarily developed in this paper.  

Key words: GRACC，Theoretical analysis，Reflective cracking，Geotextile’s choice，Performance evaluation，Design and construction method，Laboratory test，Net-current-value method