Water Stability Of Asphalt Mixture Research Articles

Investigation of the Performance of the Ecofriendly Fiber-Reinforced Asphalt Mixture as a Sustainable Pavement Material

This article presents a study to evaluate the performance of the ecofriendly calcium sulfate whisker fiber- (CSWF-) reinforced asphalt mixture as a sustainable pavement material. Asphalt mixtures containing 0.2 wt.%, 0.4 wt.%, 0.6 wt.%, and 0.8 wt.% of the CSWF were designed by the Marshall method. Asphalt mixtures without fiber were also prepared as control samples. The Marshall test, wheel-tracking test, low-temperature bending test, water sensitivity test, and fatigue test were conducted to evaluate the performance of the CSWF asphalt mixture. And the mechanism of fiber reinforcement was discussed. The results showed that the CSWF could improve the high-temperature stability and low-temperature crack resistance of the asphalt mixture. Water stability of asphalt mixtures in the presence of the CSWF was also improved. When the CSWF content was 0.4 wt.% of the total mixture, the performance of the asphalt mixture is the best. Compared with the conventional asphalt mixture, the CSWF asphalt mixture not only utilized power plant waste effectively to preserve ecosystems but also improved the performance of the pavement, which is suggested to be used in sustainable pavement construction and rehabilitation.

Study of the long-term water stability of asphalt mixtures containing steel slag aggregate

This article aims to elucidate the long-term water stability of a steel slag asphalt mixture. Both chemical composition and physical morphology of the steel slag were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), the Vickers hardness test and mercury injection testing. Methods of testing wet-dry (W–D) cycles and freeze-thaw (F–T) cycles were designed, and corresponding indices were proposed. The immersion rutting test was conducted to explore the variation in rutting depth, and consequently, the long-term dynamic water coefficient Kl was proposed to analyze the resistance to dynamic water flushing. A regression model was used to analyze the relationship between steel slag content and long-term water stability. Finally, the long-term corrosion characteristics of the steel slag asphalt mixture were analyzed by SEM. The results show that the addition of steel slag can improve the long-term water stability of the asphalt mixture. The water stability of the steel slag asphalt mixture declines with increasing W–D and F–T cycles. The degradation trend becomes gentle after 6 W–D cycles. The attenuation of the water stability of the mixture slows after 15 F–T cycles. The long-term water stability of the steel slag asphalt mixture was evaluated by comparing the residual stability after 6 W–D cycles (MS6) and the tensile strength ratio (TSR) of the steel slag asphalt mixture after 15 F–T cycles (TSR15). The Kl value of the steel slag asphalt mixture first increases and then decreases with increasing steel slag content, and the best effect in terms of long-term dynamic water corrosion resistance is observed for a 30% steel slag asphalt mixture. The SEM results show that, for steel slag asphalt mixture water damage, the steel slag hydrates and produces microcracking on the surface.

Effects of Cement–Mineral Filler on Asphalt Mixture Performance under Different Aging Procedures

Cement-containing mineral powder can effectively improve the moisture stability of an asphalt mixture; therefore, this study systematically summarizes the research status of cement–mineral fillers on the performance of an asphalt mixture and determines the limitations of related studies. In this study, long-term performance tests of styrene-butadiene-styrene- (SBS)-modified asphalt mixtures are designed and evaluated with different blending ratios of the cement–mineral powder under three aging conditions. Moreover, the effect of the cement–mineral composite filler on long-term performance of the asphalt mixture using different blending ratios is determined. Cement improves the high-temperature performance and water stability of asphalt mixtures, but only for certain aging conditions. Considering the regulations for the road performance of asphalt mixtures for three aging conditions, as well as long-term performance considerations, the results indicated that the mass ratio of Portland cement to mineral powder must not exceed 2:2. Low-temperature bending and splitting tensile tests confirmed that an excessive amount of cement filler will embrittle the modified asphalt mixture during long-term aging, thereby deteriorating the tensile properties. The mechanism by which the filler influences the performance of the asphalt mixture should be further studied from the perspective of microscopic and molecular dynamics.

Performance deterioration mechanism and improvement techniques of asphalt mixture in salty and humid environment

To prolong the service life of asphalt pavement in coastal areas, firstly, the continuous immersion, dry-wet cycle and freeze-thaw cycle in 0% (pure water), 5% and 10% NaCl solution were selected to speed up the corrosion of salty and humid environment on asphalt mixture. The changing law of mechanical property of asphalt mixture was studied by splitting test. Then the deterioration of microstructure and road performance of asphalt mixture in salty and humid environment was tested by laboratory tests. Finally, the effects of additives such as anti-stripping agent, fiber and hydrated lime on water stability and mechanical property of asphalt mixture were studied. The test results show that the splitting strength of asphalt mixture gradually decreases with the increase of action number after treated by different ways. The method of dry-wet cycle reflects the adverse effect of salty and humid environment on the performance of asphalt mixture better. Dry-wet cycle in 10% NaCl solution for twelve times is recommended to simulate the corrosion effect of salty and humid environment. After treated by dry-wet cycle in 10% NaCl solution, the high temperature performance, low temperature crack resistance and water stability of asphalt mixture all decrease by various degrees. Especially the water stability declines seriously, which residual stability and freeze-thaw splitting strength ratio cannot meet the requirement of specification. The void ratio of asphalt mixture increases first and then stabilizes with the increase of dry-wet cycles. The chloride crystal precipitates and continues to expand in the mixture, which eventually leads to the performance deterioration of asphalt mixture. Among different additives, basalt fiber achieves best effect in combating the deterioration of asphalt mixture in salty and humid environment.

Study on the feasibility of desulfurized-high-calcium-fly-ash (DHCFA) used in asphalt mixture as mineral powder

Harmless treatment and resource utilization of wastes like fly ash have always been a social difficulty and a research hot spot in the field of pavement. In this paper, samples of fly ash generated from a coal-fired power plant in Yan’an City, Shaanxi Province were collected; and a desulfurized-high-calcium-fly-ash (DHCFA) was selected as the representative to be used for the alternative of traditional limestone fine powder (LFP) in asphalt mixture. Specifically, the chemical and physical characteristics of DHCFA and LFP were studied and compared firstly. Then the performance of asphalt mortar and asphalt mixture containing different amounts of DHCFA were further investigated. XRF and XRD results show that DHCFA and LFP both have significant alkalinity, and DHCFA has relatively richer chemical composition and phase distribution. TG-DSC results show DHCFA and LFP both satisfy the construction requirements on thermal stability. Asphalt mortar results showed DHCFA had the similar effect as LFP (control sample) on the whole. Asphalt mixture results revealed that the characteristics of DHCFA such as density, composition and compaction influence the performance of asphalt mixture. DHCFA could improve the low temperature performance and water stability of asphalt mixture, while reducing the high temperature performance and strength. Above results indicates that DHCFA could be used for mineral powder in asphalt mixture, however, its dosage should be carefully verified since it has adverse impact on the high temperature performance and strength of asphalt mixture.

Material optimization and optimum asphalt content design of asphalt mixture in salty and humid environment

To improve the water stability of asphalt mixture in coastal areas, the optimization of asphalt anti-stripping agent and the design of optimum asphalt content were studied according to the characteristic of salty and humid environment. Firstly, the improved boiling water test was put forward to determine the type and dosage of anti-stripping agent suitable for salty and humid environment preliminarily. Secondly, the improvement effect of anti-stripping agent on water stability of asphalt mixture was evaluated. The type and optimum dosage range of asphalt anti-stripping agent were eventually determined. Finally, the design method of optimum asphalt content based on indirect tensile strength (ITS) for asphalt mixture in salty and humid environment was proposed. The results show that the anti-stripping agent of PA-1 (P), HT-09 (H), AMR (A) and TJ-066 (T) all improve the adhesion between asphalt and aggregate in salty and humid environment, but the performance of anti-stripping agent H declines significantly after aging. The anti-stripping agent A is recommended to improve the water stability of asphalt mixture in salty and humid environment. The optimum dosage range of anti-stripping agent A is 0.5–0.6% by weight of asphalt. The temperature of 40 °C and loading rate of 5 mm/min are proposed as appropriate condition for indirect tensile test. Replacing the stability by ITS and combining with volume indexes to determine the optimum asphalt content could ensure good water stability of asphalt mixture in salty and humid environment.

Performance Study of Warm Mix Asphalt Fiber Mixture in the Thin Overlay

Ultrathin asphalt mixture used to overlay has better road performance. Asphalt mixture can be mixed and constructed at relatively low temperatures, basing on warm mix technologies, solving issues of the thin overlay fast cool and poor compaction. Warm mix overlays is a fine thin overlay, rutting resistance of concrete and thickness 2~3cm. It composed of high quality modified asphalt, aggregate gradations, warm mix agent and polyester fiber. Indoor experimental research analyzed the performance of warm mix of ultrathin asphalt mixture water stability, high temperature stability, rutting resistance, anti-slide and noise reduction. Tests show that 5% of asphalt, 0.3% mineral fiber is the optimum dosage of warm mixed agent.

Study on Influence of Crumb Rubber on Rubber Asphalt Mixture Water Stability

As the number of cars increases, “black pollution” has been brought to the road environment in recent years. This article focuses on the environmental protection to recycle the crumb rubber. Select local limestone as aggregate and Matrix asphalt as asphalt binder materials. Put the crumb rubber into asphalt by wet process and then form the Marshall Specimens according to the aggregate gradation. Rely on the two methods, control of crumb rubber particle size unchanged and select different crumb rubber content, control of crumb rubber content unchanged and select different crumb rubber particle size. Then through asphalt mixture Void test, Cantabro abrasion loss, Coefficient of permeability, Indirect tensile strength, Indirect tensile strength ratio and Resilient modulus, compare the influence of different crumb rubber content and crumb rubber particle size on asphalt rubber mixture water stability. The regular is found: increasing crumb rubber content and particle size, asphalt rubber mixture water stability decreases.

Investigation on snow-melting performance of asphalt mixtures incorporating with salt-storage aggregates

Chloride salts are the most commonly used chemicals that serve as snow-melting agents for winter highway maintenance due to their abundance and low cost. However, the heavy use of chloride-based deicers has caused a series of environmental problems, because the deicers are directly spread on the pavement surface before snowing. Therefore, how to decrease the damage of chloride salts on pavement and environment is very important. Thus, introduction of the deicer into the asphalt mixtures and making the deicer slow release has brought a recent scientific and industrial interest. In this work, salt-storage aggregates (SSA) were innovatively prepared. Asphalt mixtures incorporating 0%, 5%, 10%, 15% and 20% SSA by volume as limestone aggregates (LSA) were prepared and their engineering properties were tested, such as high temperature stability, crack resistance at low temperature and water stability. In addition, salt-release performance of asphalt mixtures with SSA was investigated. Finally, field snow-melting test was conducted by outdoor experiments of the asphalt mixtures. The results show The SSA possesses excellent water stability, high mechanical strength and salt-storage function. The properties of asphalt mixtures with SSA can meet the requirements of specification, but the influence of SSA on water stability of asphalt mixtures should be noticed. The electrical conductivity of asphalt mixtures increases with the increase of SSA content. Salt precipitation amount per unit area increases and then gradually becomes stable with the increase of soaking time. Salt precipitation amounts from asphalt mixtures increase with the standing time and the SSA content. The asphalt pavement with SSA can possess satisfied snow-melting performance in reference to the simulated field tests.

Research on the Evaluation Method of Water Stability for Large Size Aggregate Particle Asphalt Mixture

Aiming at the deficiency of the current asphalt mixture test procedures using the traditional Marshall compaction molding test specimens method to evaluate water stability of asphalt mixture, large size aggregate particle asphalt mixture water stability test method, evaluation index and standard are proposed, namely the freeze-thaw cycles dynamic stability ratio index is adopted to evaluate asphalt mixture water stability, the freeze-thaw cycles dynamic stability ratio ≥ 85% is required and verified by experiment.

Research of Coarse Grading Asphalt Mixtures Based on Grey Relational Analysis

Grey relational analysis (GRA) is an important data handling techniques. In this paper, combining the characteristics of asphalt mixture, the method of GRA is applied to the study of coarse grading. The high temperature stability, low temperature cracking resistance and water stability of asphalt mixture with different grading were evaluated in the laboratory. The results showed that OGFC-25 gradation apply to asphalt mixture that demand high temperature stability. Similarly, ATB-25 gradation benefit low temperature performance and SUP-25 benefit water stability.

Effect and its Mechanisms of Hydrated Lime on Water Stability of Hot Asphalt Mixture

The mechanism that hydrated lime can improve water stability of asphalt mixture was analyzed through contrasting the performance of hydrated lime and ordinary limestone ore filler. The test results indicated that hydrated lime can obviously improve the water stability of asphalt mixture.

The Effects on Pavement Performance of AC-20 Asphalt Mixture Addicted with Polyester Fiber or Anti-Rut Agent

The pavement performance of AC-20 asphalt mixture added with certain polyester fiber or the anti-rut agent are studied in this paper. By analyzing the high temperature stability and water stability of asphalt mixture through the indoor test, it can be concluded that: after adding polyester fiber and anti-rut agent, the pavement performance of asphalt mixture has the remarkable enhancement, it can be better adapted to our heavy traffic requirements.

Research on Evaluation Index of Water Stability for Asphalt Mixtures

Aiming at the deficiency of the water stability evaluation index of bituminous mixtures by immersion Marshall test in present specifications in china, the water stability of various of bituminous mixtures test pieces was analyzed by comparing freeze-thaw splitting tensile tests with immersion Marshall stability tests. There is larger difference between the evaluation results of immersion Marshall test and freeze-thaw splitting tensile test. The residual stability by immersion Marshall test is rarely inconsistent with regulatory requirements, Residual modulus is brought up to evaluate the water stability of bituminous mixtures. Residual modulus suggested to evaluate the water stability of asphalt mixtures has the similar trend with freeze-thaw splitting tensile strength ratio and the residual modulus threshold valve 0.85 is recommended.

Influence of Fine Aggregate on the Performance of Asphalt Concrete

The performance of asphalt concrete mixed with 3 types of fine aggregate respectively (i.e. natural sand, limestone, basalt) are compared. The results of Marshall test and rutting test show that the high temperature performance of asphalt mixture mixed with basalt is the best, that of asphalt mixture mixed with natural sand is the worst, and that of asphalt mixture mixed with limestone is between the above two. The result of immersion Marshall test show that the water stability of asphalt mixture mixed with basalt and that of asphalt mixture mixed with limestone are similar, but better than that of asphalt mixture mixed with natural sand. Therefore, it indicates that the machine-made aggregate (of basalt or limestone) have better pavement performance and environment benefit than the natural sand.

Study on Road Performance of Phase-Change Temperature-Adjusting Asphalt Mixture

Mixing the composite phase change material (CPCM) to asphalt mixture is a new way to solve the worldwide problem of the low-temperature cracking and high temperature rutting of the asphalt pavement. Asphalt mixture with CPCM can remain in the ideal working temperature range for a relatively long time. This paper analyzes the influence of the contents of CPCM on its road performance by laboratory testing. The study shows that mixing CPCM to asphalt mixture had little effect to the optimal asphalt content. For CPCM prepared by polymer shape-stabilized method, the high-temperature stability and the water stability of asphalt mixture increases firstly and then decreases the low-temperature anti-cracking stability decreases firstly and then increases with the increasing of CPCM. For CPCM prepared by carrier-adsorbed packaging process, the high-temperature stability decreases, low-temperature anti-cracking stability decreases firstly and then increases, the water stability increases firstly and then decreases with increasing of CPCM. The results indicate that CPCM has significant influences on its road performance. The optimal content of CPCM is around 0.3%.

Study of Water Stability of Asphalt Mixture Based on Residual Water

At present, AC, a major gradation type of asphalt mixture, is widely used in highway construction in China. Due to internal large porosity, the water of road surface draining quickly, OGFC pavement is also widely used. However, water is easier flow into OGFC asphalt pavement than ordinary asphalt pavement. So the water stability of OGFC asphalt pavement is particular important. We get the following conclusion by the test of residual water and water stability based on the two gradations asphalt mixture of AC and OGFC. Residual water stays in AC asphalt mixture for about one week.While the residual water stays in OGFC asphalt mixture for more than three months. When the residual water is 50% in AC, the water stability is the worst. When the residual water is 75% in OGFC, the water stability is the worst.

Experimental Study on Water Stability of Asphalt Mixture

To improve water stability, we mixed asphalt mixture with cement, slag micro powders and lignin fibers, respectively. The Marshall immersion and freeze-thaw splitting tests were carried out. It is shown that cement replacing mineral powders can improve the water stability of asphalt mixture, especially at the content of 1/3 mineral powders, with a Marshall stability of 11.50 kN and a soaking residual stability of 92.46%, increasing by 10.79% and 6.58%, respectively, than those without any cement. According to the results of cement replaced by slag micro powders, its stability increases by 1.38kN, and the soaking residual stability is 90.64%, but the freeze-thaw splitting tensile strength slightly decreases. It is indicated that the water stability of the asphalt mixture can be improved by adding 0.3% lignin fibers, the soaking residual stability increasing from 86.75% to 97.41% and the ratio of freeze-thaw splitting tensile strength rising from 60.94% to 80.29%. It is concluded that the best effect can be reached by adding 0.3% lignin fibers.

Experiment Study of Water Stability of Fiber-Reinforced Asphalt Mixture

To study the influence of fiber on the water stability of asphalt mixtures, the optimum dosage of asphalt and fibers are studied by the method of Marshall test and rut test. The results demonstrate that the optimum dosage of asphalt and fibers are 4.63% and 0.30%, respectively. Then the improved effects of basalt fiber on water stability of asphalt mixtures are evaluated through immersed Marshall test and freeze-thaw splitting test according to related specifications. The results show that the freeze-thaw splitting strength and splitting strength without freeze-thaw of fiber-reinforced asphalt mixture are improved to some extent compared with control mixture. Splitting strength without freeze-thaw of basalt, polyester and xylogen fiber-reinforced asphalt mixture is increased by 36.4%, 15.4% and 6.2%, and freeze-thaw splitting strength is increased by 55.2%, 28.7% and 14.5%. It can be concluded that fiber can remarkably improved the water stability of asphalt mixtures, besides; the improvement effects of basalt fiber are superior to polyester fiber and xylogen fiber.