半柔性材料抗裂性能评价与改善措施的研究

发布时间：2018-05-06 02:29

本文选题：半柔性路面（SFP）材料 + 多孔沥青混合料　；参考：《华南理工大学》2014年硕士论文

【摘要】：半柔性路面（SFP）结合了混凝土和沥青路面的特点，它是利用特别设计的水泥砂浆填充多孔沥青混合料25-32％的空隙，待其凝结硬化后形成刚柔并济的路面结构。这种路面将两种常规路面——沥青和混凝土路面相结合，消除各自的缺点。半柔性路面最初在六十年代末提出，后来发现是有效防止汽油溶解和抗磨的表面材料。由于较高的承载能力和抗车辙性，半柔性路面还非常适合重载交通。半柔性路面的主要问题是开裂。沥青和水泥的弹性模量的差异是引起半柔性路面开裂及其它病害的主要原因。半柔性路面的开裂主要是体现路面刚性部分的水泥砂浆的刚性造成的。尽管从60年代起半柔性路面就已经开始采用，并引起了许多研究者的兴趣，但目前仍没有半柔性路面的多孔沥青骨架和水泥砂浆的设计标准，而只有应用技术指南、生产技术手册和一些研究报告。因此，本文的目的是研究一种合适的水泥砂浆，使它自身和沥青混合料的弹性模量可有效协调，以控制裂缝。半柔性路面材料设计主要有两部分：多孔沥青骨架混合料及水泥砂浆设计。设计多孔沥青骨架混合料的空隙率时，大部分研究者认为25%~32%较合适。设计水泥砂浆时，研究者添加不同的外加剂或添加剂配制所需砂浆。外加剂包括有粉煤灰、橡校、乳化沥青、羧酸醚、一些超增塑剂和树脂混和物等。水泥砂浆的工作性能（流动性）的差别取决于这些外加剂或添加剂的配比和使用类型。为设计出更合适填充多孔沥青骨架混合料的水泥砂浆，，本研究在普通水泥砂浆配合比设计基础上，采用粉煤灰、乳化沥青和羧基丁苯乳胶三种外加剂，优化普通水泥砂浆设计。根据一系列试验，在不添加外加剂的情况下，分析和评价不同水灰比情况下的水泥砂浆的机械性能，确定符合半柔性路面性能要求的普通水泥砂浆最佳配合比。最后确定水灰比为0.54、0.60和0.66，分别设计9组添加了不同比例和种类外加剂的水泥砂浆。水灰比的确定，是为了使水泥砂浆可以更容易地流入多孔沥青骨架，而无需过多的震动，且形成的砂浆强度足以抵抗路面在寿命周期内可能发生的应力应变，防止路面意外损害。分析各试件的力学性能试验结果后，确定高流动性水泥砂浆混合物的配比为：水灰比0.63，粉煤灰5%，乳化沥青4%，羧基丁苯乳胶9%。为研究对比添加和未添加外加剂的砂浆力学性能，总共拌合10组水泥砂浆，其中包括未掺加任何外加剂的普通水泥砂浆，另外分别普通水泥砂浆中分别添加粉煤灰、乳化沥青和羧基丁苯乳胶三种外加剂，每种外加剂选用三种掺量，共9组。每组水泥砂浆制作6个小长方体试件，进行干缩试验、抗折强度试验和抗压强度试验。设计制作三种空隙率分别为24%、28%和32%的多孔沥青混合料车辙板试件，分别灌浆三种不同的水泥砂浆，测定其流动性、抗弯、抗压、收缩等性能，以确定其机械性能。对比分析不同外加剂的水泥砂浆和不同空隙率的多孔沥青混合料对半柔性路面机械性能的影响。研究认为：多孔沥青混合料的空隙率对水泥砂浆中添加的外加剂种类的性能没有显著影响。然而，值得注意的是，空隙率越高，半柔性路面材料的机械性能越好。这是因为水泥砂浆形成了半柔性路面的刚性部分，空隙率使其含量增加，使得其更像混凝土路面。结果表明，不考虑试验类型和多孔沥青混合料的空隙率，相比比其它外加剂，添加羧基丁苯乳胶的水泥砂浆（半柔性路面材料）具有更高的稳定性（动稳定性、马歇尔稳定性、流值、劈裂拉伸强度）。引入内聚区模型概念，分析半柔性路面材料类型的抗裂性能。利用双悬臂梁的线弹性理论，得到解析解。根据杨氏模量（E）、最终位移（）、梁高（H）、内聚断裂能（Gc），建立裂缝长度和位移之间的关系式。如模型的图表所观察到的开裂现象，半柔性路面材料的内聚能Gc（粘结强度）越高，其抗外部变形能力越好，裂缝长度越小。添加羧基丁苯乳胶的水泥砂浆是三种添加不同外加剂的水泥砂浆中表现最稳定的，添加乳化沥青的水泥砂浆较稳定，而添加粉煤灰的水泥砂浆在几乎所有试验中都最不稳定。
[Abstract]:The semi flexible pavement (SFP) combines the characteristics of concrete and asphalt pavement, which is filled with a specially designed cement mortar to fill the void of the porous asphalt mixture, 25-32%, to form a rigid and flexible pavement structure after setting and hardening. The pavement combines two conventional pavements, asphalt and concrete pavement, to eliminate their shortcomings. Semi flexible pavement was originally proposed at the end of 60s. It was later found to be a surface material to effectively prevent gasoline dissolving and antiwear. Semi flexible pavement is also very suitable for heavy load traffic due to its high bearing capacity and rutting resistance.
The main problem of semi flexible pavement is cracking. The difference between the modulus of elasticity of asphalt and cement is the main cause of semi flexible pavement cracking and other diseases. The cracking of semi flexible pavement is mainly caused by the rigidity of cement mortar which embodies the rigid part of the pavement. Although the semi flexible pavement has been adopted since 60s, it has been caused by the semi flexible pavement. Many researchers are interested, but there is still no design standards for porous bitumen skeleton and cement mortar for semi flexible pavement, but only application technology guide, production technology manual and some research reports. The purpose of this paper is to study a suitable cement mortar to make the modulus of its own and bituminous mixture effectively synergistic. Adjust to control cracks.
There are two parts in the design of semi flexible pavement material: porous asphalt skeleton mixture and cement mortar design. When designing the void ratio of porous asphalt mixture, most researchers think 25%~32% is more suitable. When designing cement mortar, researchers add different admixtures or additives to prepare the mortar. Ash, acorn, emulsified bitumen, carboxylic ethers, some superplasticizers and resin mixtures. The difference in the working performance (liquidity) of cement mortar depends on the ratio and type of use of these admixtures or additives.
In order to design cement mortar which is more suitable for filling porous asphalt framework mixture, the design of ordinary cement mortar is optimized by using three kinds of admixtures, fly ash, emulsified bitumen and carboxyl styrene butadiene latex, on the basis of the mix ratio design of ordinary cement mortar.
According to a series of experiments, the mechanical properties of cement mortar under the condition of different water cement ratio are analyzed and evaluated without additive, and the optimum mix ratio of ordinary cement mortar which meets the requirements of semi flexible pavement performance is determined. Finally, the water cement ratio is 0.54,0.60 and 0.66, and 9 groups of different proportions and kinds of admixtures are added. Cement mortar. The determination of water cement ratio is to make cement mortar easy to flow into the porous asphalt skeleton without too much vibration, and the strength of the mortar is enough to resist the possible stress and strain that may occur during the life cycle of the pavement and prevent the accidental damage of the pavement. The ratio of mobile cement mortar mixture is: water cement ratio 0.63, fly ash 5%, emulsified bitumen 4%, carboxyl styrene butadiene latex 9%.
In order to study the mechanical properties of the mortar which was added and without additive, 10 groups of cement mortar were mixed, including ordinary cement mortar without adding any admixtures. In addition, three kinds of admixtures were added to the ordinary cement mortar, including fly ash, emulsified asphalt and carboxyl styrene butadiene latex, and three kinds of admixtures were selected, with a total of 9 groups. Each group of cement mortar made 6 small cuboid specimens for dry shrinkage test, flexural strength test and compressive strength test.
Three kinds of porous asphalt mixture rutting plate specimens of 24%, 28% and 32%, respectively, were designed and made of three different kinds of cement mortar, respectively, to determine their fluidity, bending, compression, shrinkage and other properties to determine their mechanical properties. Comparison and analysis of different additives of cement mortar and different porosity of the porous asphalt mixture to semi flexible. The effect of pavement mechanical properties is that the porosity of porous asphalt mixture has no significant effect on the properties of admixtures added in cement mortar. However, it is worth noting that the higher the void ratio, the better the mechanical properties of the semi flexible pavement material. This is because the cement mortar formed the rigid part of the semi flexible pavement. The porosity increases its content, making it more like concrete pavement.
The results show that the cement mortar (semi flexible pavement material) with carboxyl styrene butadiene emulsion (semi flexible pavement material) has higher stability (dynamic stability, Marshall stability, flow value, splitting tensile strength) than the other admixtures without considering the test type and the porosity of the porous asphalt mixture.
The concept of cohesive zone model is introduced to analyze the crack resistance of semi flexible pavement material. By using the linear elastic theory of the double cantilever beam, the analytical solution is obtained. According to the young's modulus (E), the final displacement (H), and the cohesive fracture energy (Gc), the relationship between the length and the displacement of the crack is established.
The higher the cohesive energy Gc (bond strength) of semi flexible pavement material is, the higher the cohesive energy of the semi flexible pavement material is, the better its resistance to external deformation and the smaller the length of the crack. The cement mortar with carboxyl styrene butadiene emulsion is the most stable in the three kinds of cement mortar adding different admixtures, and the cement mortar adding emulsified asphalt is more stable. The cement mortar added with fly ash is the most unstable in almost all tests.

【学位授予单位】：华南理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U414

【参考文献】