Papers by Keyword: Water Damage

Abstract: The performance of added 50% reclaimed asphalt (RAP) mixtures was investigated by four-point bending fatigue tests (FPBT). Mixtures with 50% RAP were modified with SBS polymer, diatomite (D) and hydrated lime (HL). Ten specimens were produced and fatigue of specimens was evaluated with FPBT. Some samples give the fatigue breaking cycle compatible with each other. In some samples, the number of cycles is much higher than the average breaking load. Some samples may deteriorate in a short time before the end of test. Although the briquettes are mixed homogeneously for longer mixing times and produced with great care, inconsistent results can be obtained. If water damage is applied to briquettes due to the presence of HL, more compatible results can be obtained. The use of SBS-HL and rejuvenating oil at high RAP ratios will provide more compatible results. As a result of 50% stiffness reduction, the difference in the remaining stiffness values is usually 2-3 times, while there are huge differences between the cycle numbers that cause this. In terms of sustainable and long-term performance, the homogeneity of the pavement composition appears to be essential, having a much more pronounced effect than the number of loadings.

Abstract: The life cycle of a road engineering usually contains multiple stages. It starts from design, through the construction, usage and damaged to discarded. Early disease water damage of asphalt pavement has great influence on the service life of road surface. Through analyzing the mechanism of water damage and summarizing the main forms of water damage, this paper puts forward the reasonable distribution of asphalt mixture and the good rigidity relationship between base and surface, which is the key factors to avoid water damage. We analyze and summarize the advantage of drainage asphalt pavement in the prevention and control of water damage of asphalt pavement in order to apply it in the practice of engineering.

Abstract: Through a highway asphalt pavement condition survey and analysis of the main causes of disease, through material selection and grading design, the design of the treatment structure, class structure using the drainage layer, exclude the internal structure of the water surface; focused on solving the asphalt pavement water damage issues, effectively extending the life of the highway.

Abstract: Under normal atmospheric pressure conditions, volume suddenly increases about 11% when the water freezes and decreased when the ice melts. The pressure can reach up to 2500 times of atmospheric pressure in the closed space when the water freezing. This is a very important characteristic of the natural world and the industrial. In low temperature condition, the snow on the pavement is easy to melt and freeze, and it will affect the road safety, increase the cracking of the road and accelerate asphalt pavement water damage. Bitumen is a mixture consisting of some extremely complex polymer hydrocarbons and hydrocarbon derivatives of non-metallic (oxygen, sulfur, nitrogen). Deicing salt is used to prevent freezing in that area, chloride salt is its main ingredient. When the water melting point reduced, it is not easy to icing but to penetrate the asphalt pavement. If the temperature is continued to reduce, salt solution will still freezing. At last, the pavement will form water damage in repeated freeze-thaw cycles conditions.

Abstract: According to laboratory physical simulation methods, Achieve the infiltration experiment of overheated steam in the porous medium. The experiment researched overheated steam’s improvement to damage and undamaged porous mediums. Permeability was increased 1 to 4 times in the damaged porous mediums, 3 to 6 times in those undamaged. The microstructure of porous medium is characterized by scanning electron microscope photos. A lots of mineral microcrystal adhered on the initial rock particle surface. After the infiltration experiment of overheated steam, mineral microcrystal decreased obviously, and the rock particle surface changes into even and smoothly, which made the filtration resistance precipitous declined. Based on theory assumptions, production calculation formulas were derived in some given conditions. And the regular pattern plate map out, which affected by overheated steam heating radius and water-damaged radius. The results turns out that, inject overheated steam can achieve obviously production increasing.

Abstract: Asphalt pavement of water damage is a major form of our country highway asphalt pavement damage, the paper analyzes pavement structure internal water source, water damage of asphalt pavement of the influence factors, through the determination of the three indexes and asphalt of asphalt mixture splitting tensile strength, water erosion proof of asphalt mixture and its influence, and put forward the corresponding prevention and control measures to improve the pavement performance and extend the service life of road surface has important practical value.

Abstract: Water damage in asphalt pavement is related to the interaction between cracks and hydrodynamic pressures caused by the vehicle. A 3D finite element model of the hydraulic crack in asphalt pavement was built to analyze the crack propagation character under vehicle load. The influence of asphalt pavement structure parameters, vehicle speed and crack geometric parameters of hydraulic crack were discussed. Then the differences, between aqueous cracks and cracks without water, were compared. The research results had the guiding meaning for anti-water damage design of asphalt pavement.

Abstract: A centrifugal earth structure deformation test system has been developed to study the mechanism and pattern of subgrade damage as caused by water wetting to the widened roads in collapsible loess areas. It incorporates an upgraded electric sensor logging system and a centrifugal field image pickup system and provides a centrifuge model test platform for both the new road and the original road that are subject to water wetting and infiltration. A centrifuge test model on which actual stress distribution can be simulated was set up to study the forms of water damage to the widened subgrade. In the same time, special research was conducted with regard to the working mechanism of geogrid in the splice between the new road and the old, as well as the effect of dynamic compaction on loess foundation. It indicates that high water content in the toe of slope of a widened road could significantly influence the stability of subgrade. Local instability in loess foundation, as caused by the presence of high level of underground water especially after a heavy rain, could be a great threat to the integrity and safety of the subgrade on top of it. In this case the loess foundation, which is locally wetted and softened by water, would undergo a reduction in shearing strength and gradually lose its stability under the load of subgrade, that eventually results in the sliding or separation between the new subgrade and the old. The reinforced materials used in the splice can enhance soil hardening and help establish soil arching effect under which the settlement of subgrade is well controlled.

Abstract: The water damage resistance performance of micro-surfacing is studied by means of gradation and clay content; It can be found that the cleaness of powder lot in the mineral aggregates plays an important role on water damage resistance ability of micro-surfacing; The MB test is proved to be more convenient for evaluating the cleaness and clay content in aggregates than the SE test, and the MBV for micro-surfacing is given so as to make sure the favorable water resistance ability of the mixture.

Abstract: Analyze and study the deformation and damage of asphalt pavement which is under the combined action of seepage and vehicle payload by the finite element analysis software ANSYS. Through the study and analysis of the deformation and damage of the asphalt pavement in the three cases of seepage, vehicle payload, and the combined action of seepage and vehicle payload, the study shows: the damage of the asphalt pavement emerges mainly under the vehicle payload, but after the seepage, the damage under the combined action of seepage and vehicle payload will be more serious.