Papers by Keyword: Asphalt Pavement

Abstract: Interlayer bonding within a multilayered pavement system plays an essential role in the overall performance of the pavement structure. Therefore, studying the interlayer shear strength (ISS) as a major index of the bonding strength and its accurate evaluation is of great importance. The main objective of this research is to assess the ISS of pavement using an experimental and statistically rigorous approach. The results showed that the ISS is highly temperature-dependent, experienced a rapid decline with increasing temperature. As tack coat rate increased, the ISS initially increased to reach a pick at 0.8kg/m² rate and then started to decline. The ISS demonstrated an almost linear correlation with vertical pressure at all temperature levels. Two-way factorial analysis of variance (FAV) underscored the significant impact of any two, namely temperature (T), tack coat rate (TC), and vertical pressure (VP), on ISS results. However, three-way FAV results indicated that the combined effect of T, TC and VP did not hold statistically significant influence on ISS. Moreover, all ISS models developed in this study were statistically significant at a 0.05 significance level, with a good coefficient of determination (R² =0.73) for multiple linear regression (MLR) and an excellent R² of 0.976 for polynomial regression (PR).

Abstract: As the important part of expressway, the construction technology of asphalt pavement will contribute to the production of greenhouse gases and other volatile organic compounds (VOCs), which has a significant impact on the environment. In order to further analyze the composition, distribution and release of VOCs during asphalt pavement construction, the VOCs emission during paving and rolling were measured through field investigation and sampling. The results show that there are approximately 100 kinds of VOCs substances detected due to the complex organic component of asphalt binder, which is a critical factor to influence the VOCs emission during asphalt pavement construction. During the paving process, the largest VOCs release is 1015.05 ug/m³. With the increase of rolling times, the pavement temperature gradually decrease, and the VOCs emission drops to 266.73 ug/m³. The content of the 10 kinds of substances with the highest concentration accounts for more than 50% of the total VOCs content, in which the proportion of aliphatic hydrocarbons (ALH) and oxygenated hydrocarbon (O-HYD) of the paving process are the highest, while the proportion of aromatic hydrocarbons (ARH) is dominated in the rolling process. The results are vulnerable to the external environment, especially at lower emission level. The relevant research results have certain guiding significance for the control and treatment of harmful gas emission in the construction process of asphalt pavement.

Abstract: This paper reviews the functionalization of nanomaterial especially nanoclay and nanosilica as commonly used material, process, and effect from both material to mechanical properties of the asphalt pavement. On the other sight, discussion about laboratories scale development on road site of engineer application and cost of nanomaterial functionalization are discussed then. In recent years, nanomaterial developed broadly in various applications. One of that application is asphalt pavement mixtures. Its nanoscale allow modification with its promise properties like specific surface area and spatial confinement. These promising properties lead to improve mechanical properties of nanomaterial asphalt mixture, the compressive strengths and heat resistance of the composite, the tear, and also shows good dispersion. Nanosilica and nanoclay are the common nanomaterial applied in asphalt pavement mixtures. Some studies reported that both materials could decrease asphalt road damage and failure due to poor drainage, or layer composition weakness. Nanomaterial play as filler or may be as the binder to improve the drainage or layer composition weakness. However, upcoming challenge appears as contrast different between nanoscale of nanomaterial and large scale of asphalt mixture in ton. This case lead to the high cost of nanomaterial in high purity and particle size. Furthermore, nanomaterial require to high skilled technician in preparation and modification. Therefore, engineer should modify the desired nanomaterial in those requirements which then low-cost mixture asphalt pavement modification can be achieved.

Abstract: The paper deals with the influence of geosynthetic reinforcement systems on the quality of asphalt bonding layers. A reinforcing element in the form of a fiberglass grid is incorporated into the road structure between two asphalt layers to prevent the formation of cracks and to reduce the tendency of their subsequent propagation throughout the asphalt layers. At the same time, however, they form a potential weak interlayer on which adjacent asphalt layers may slip. The total 90 drilled cores taken from a laboratory-produced two-layer slabs were subjected to the Leutner shear test. The selection of individual specimens took into account both the type of reinforcement element and the amount of applied bituminous emulsion.

Abstract: Recently, potholes have drawn attention as a major pavement distress. In Korea and other countries, slaked lime is used to improve the moisture resistance of asphalt mixtures in order to prevent road damages by moisture. The present study was conducted to evaluate the moisture resistance of asphalt mixtures containing air-cooled slag having a chemical composition similar to that of slaked lime. To evaluate the moisture resistance of asphalt mixtures containing air-cooled slag, a moisture resistance test that is applied in Korea and other countries was performed. The evaluation of the moisture resistance of asphalt mixtures containing air-cooled slag showed that the coverage ratio measured by the dynamic immersion test was about 80%, which was similar to that of the asphalt mixtures containing slaked lime. In the case of the indirect tensile strength test, the TSR value tends to increase with increasing the air-cooled slag content of the specimens. But the indirect tensile strength was slightly lower in the specimen containing 3% air-cooled slag. The Hamburg wheel tracking test showed that the moisture resistance of the specimens produced in a laboratory and in a plant was good but that of the specimen containing 3% air-cooled slag was slightly lower. The laboratory experiment performed in the present study showed that the moisture resistance was improved by the addition of air-cooled slag, which has a similar composition with slaked lime, to asphalt mixtures. However, when the entire filler of the asphalt mixture was replaced by air-cooled slag, the strength was slightly decreased, indicating that an appropriate amount of air-cooled slag should be added. The applicability of air-cooled slag to asphalt pavement material may need to be studied through a microstructure analysis and a long-term pavement performance test to investigate the mechanism more accurately.

Abstract: Layered double hydroxide containing chloride (Cl^- LDHs) was obtained by calcination recovery method, and the self-deicing coating was prepared by blending Cl^- LDHs and SBR modified asphalt emulsion. Freezing point and carbon steel corrosion rate of Cl^- LDHs solution were tested. Deicing performance of the self-deicing coating was investigated by testing the melting ice point of coating surface and the adhesion force between ice and self-deicing coating,then the deicing durability were evaluated by immersion test and microscopic observation. The results showed that the freezing point of solution with 20wt% Cl^- LDHs was-9.1°C. The corrosion rate of carbon steel in 20wt.% Cl^- LDHs solution was 1.17mm/a, which was only a little higher than corrosion rate of carbon steel in tap water. When the amount of the self-deicing coating with 8wt.% Cl^- LDHs was 400 g/m², the melting ice point on the coating surface was-3.2°C and the adhesion force between ice and self-deicing coating was 24N at-15°C. After immersion in water, the deicing performance and microstructure of the self-deicing coating almost unchanged, which indicates that Cl^- LDHs in the self-deicing coating wasn’t dissolved and the coating had excellent deicing durability.

Abstract: A silicone based self-deicing coating was prepared by blending of silicone solution and organics-coated NaCl deicing additive. The effects of deicing additive content and coating amount on freezing point of coating surface and adhesion force between ice and coating were investigated. The deicing durability of self-deicing coating was evaluated by immersion test. And the influence of silicone based self-deicing coating on friction coefficient and structure depth of asphalt pavement was researched. The experimental results showed that freezing point of coating surface and adhesion force between ice and coating decreased with the increase of the organics-coated NaCl content, freezing point and adhesion force of the self-deicing coating with 6wt.% organics-coated NaCl were-5.2°C and 24.5 N respectively. Immersion test results showed that the deicing performance had only a small reduction after immersion in water for 3 days,which indicated the self-deicing coating had good deicing durability. Moreover, silicone based self-deicing coating had slight influence on friction coefficient and structure depth of asphalt pavement due to the good permeability of silicone solution. The friction coefficient of asphalt pavement decreased by 10.4%, and the structure depth decreased by 6.1% when the amount of the self-deicing coating was 300 g/m².

Abstract: Environmental and climatic factors directly affect the temperature of asphalt pavement layers. Air temperature is one of the most important environmental factors that significantly affect the temperature distribution profile of asphalt pavement layers. It is important therefore, to comprehend the asphalt strength characteristics because of the differences in asphalt pavement designs. This study was conducted in ​​tropical area with high humidity in Indonesia. A testing method was carried out to measure both temperature and humidity using thermocouples equipped with data logger and an application program of SAGA Technology. Measurements were taken for consecutive seven sunny days in July 2014. The average values obtained ​​for hourly air temperature and humidity were ranging from 24.92 to 36.98 °C and from 50.31 to 83.69% respectively. Meanwhile, pavement surface temperatures measured at 0, 20 and 65 millimeters depths were varied from 25.29 to 45.65 °C, from 25.37 to 43.59 °C, and from 26.70 to 38.54 °C respectively. Both air and asphalt pavement temperatures are sharply increased from 10:00 a.m. to 02:00 p.m. and are gradually decreased afterward.

Abstract: This paper established a three-dimensional model of asphalt pavement by finite element analysis method, studied the effects of vehicle braking on the asphalt pavement, and analyzed the mechanical law of asphalt pavement through comparing the stress of pavement asphalt when the vehicle is in uniform motion or braking condition. The results show that the vertical stress, vertical displacement and horizontal shear stress of the asphalt pavement increase significantly while the vehicle is under the braking condition. In every asphalt pavement structure layer, the maximum horizontal shear stress under vehicle braking condition are all about four times to that of under vehicle uniform motion, so it’s necessary to significantly improve the shear strength of the asphalt pavement in these sections which often bear automobile braking force.

Abstract: The Beijing-Tianjin-Tanggu expressway is the first highway which is built by using World Bank loan in china. With the influence of service life increasing and traffic growing, the diseases appear such as rut, crack and poor flatness, so the use performance of the highway obviously degrades. Pavement overhaul effectively reduces the appearing of pavement diseases and prolongs the service life of the road. This paper conducts a detailed research on the engineering management and construction quality control of the Beijing-Tianjin-Tanggu expressway overhaul which has strong reference significance on highway overhaul.