Porous Asphalt Research Articles

Integrated assessment of available water volume for sustainable sponge city construction - A case study in Xi'an, China.

To address the lack of theoretical guidance for sponge city construction (SCC) in China, this study introduces a method to evaluate the available water volume (AWV) in urban watersheds. This evaluation is based on the water balance relationship, water volume, and ecological water demand (EWD). The Xi'an urban area was selected as a case study due to its water shortage and flooding issues. Results show monthly surface and subsurface AWV ranging between 53.06 and 53.98 million m3 and between 8,701.89 and 8,898.14 million m3, respectively. By maximizing the potential for surface AWV, an annual water supply of 527.75 million m3 could be provided, surpassing the annual artificial water consumption of 394.20 million m3, effectively addressing water scarcity. During the rainy season, implementing measures such as employing permeable paving materials, establishing wetlands and rainwater gardens, and constructing lakes and reservoirs can mitigate flooding caused by rainfall exceeding 32.8 mm. While the subsurface space in Xi'an holds significant potential for subsurface AWV utilization, revitalizing the ecological environment of subsurface water is crucial. Overall, the AWV theoretical framework offers a comprehensive solution to water shortage and flooding issues in the Xi'an urban area, serving as a vital theory for SCC.

The Consequences of Dimension Reduction for Open Graded Friction Course (OGFC) Asphalt Mixtures: Morphological Characteristics and Finite Element Model (FEM) Simulation

Asphalt mixtures exhibit complex mechanical behaviors due to their multiphase internal structures. To provide better characterizations of asphalt pavements under various forms of potential distress, a two-dimensional (2D) finite element simulation based on images of asphalt mixtures can be used to increase computational efficiency and reduce labor consumption. Nonetheless, using a representative image to eliminate the influence of dimension reduction from three dimensions to two dimensions is of great significance for attaining a reliable simulation result. Therefore, in this study, we investigated the consequence of dimension reduction for open-graded asphalt mixtures (denoted as OGFC-16), including a comprehensive characterization of these 2D models in terms of their morphologies and the similarities between them. This study aimed to reveal the variation in a 2D finite element simulation when applied to open-graded asphalt mixtures. Structural compositions, gradations, the aspect ratios of aggregates, and aggregate orientations were counted and calculated. In addition, the cosine similarity and structural similarity index measure (SSIM) were also calculated. Consequently, we performed a statistical analysis on the aforementioned indicators to quantitatively identify the discrepancy in the 2D images caused by dimension reduction. The results demonstrate that this 2D simulation might not be sufficient for representing the realistic mechanical performance of asphalt mixtures due to the remarkable variations in the image morphologies in different 2D images. However, the basic rules of stress behavior within structures can be accurately simulated. A compensative methodology for conducting a 2D simulation of open-graded asphalt mixtures should be based on a morphological characterization, considering structural compositions and the structural similarity index measure.

Use of municipal solid waste incineration (MSWI) bottom ash as a permeable subgrade material: An experimental and mechanism study

ABSTRACT As a traditional method of waste treatment, municipal solid waste incineration (MSWI) has become one of the main methods of urban waste treatment. However, as a byproduct of MSWI, a large amount of MSWI bottom ash is not reused in current practice. This study innovatively posits MSWI bottom ash as an eco-friendly adsorbent rather than a pollutant, exploring its potential application as a permeable subgrade material. The results reveal that MSWI bottom ash exhibits promising properties to serve as a permeable subgrade material to achieve the permeability and improve the sustainability for subgrade. Due to the arrangement of its particles, it shows excellent performance in shear strength and permeability, which are comparable to or surpass those of sandy soils. The average pore width of 14.200 nm allows heavy metal substances to be encapsulated within the matrix, significantly reducing their leachability, thereby aligning with environmental friendliness standards. Its adsorption capacity is about 6.60 mg/g, and the adsorption capacity per volume is 3.66 times and 2.04 times that of fly ash and clay, respectively. The mechanism analysis shows that the adsorption process is monolayer heterogeneous adsorption. This paper presents a novel perspective on reusing MSWI bottom ash and provides evidence supporting its effective utilization as a permeable subgrade material, offering substantial environmental benefits through enhanced adsorption ability. Implications: Municipal solid waste incineration (MSWI) is a common method for municipal solid waste treatment, while the MSWI bottom ash is often not reused. This paper explored the explores the feasibility of using MSWI bottom ash as a permeable road base material. The results show that the particle arrangement enables excellent shear strength and permeability, comparable to sandy soil. It meets safety requirements for the leaching of heavy metals and acts as an adsorbent for pollutants leaching from permeable pavements. Furthermore, the mechanisms underlying these behaviors of MSWI were confirmed by microstructural and mineralogical analyses. These indicate that MSWI bottom ash has great potential as a permeable road base material. This paper provides a clear understanding of the physical, mechanical and environmental properties of MSWI bottom ash, which can promote its reuse in practice.

The Value of Traditional Ecological Knowledge in Stormwater Management: A Case Study of a Traditional Village

In recent years, floods have occurred frequently in urban and rural areas around the world, causing heavy casualties and property damage. In contrast, some traditional Chinese villages have never flooded. It is hypothesized that these villages, because of their long-term adaptations to their environment, hold necessary ecological knowledge regarding stormwater management so that damaging flooding can be avoided. Previous studies on the traditional ecological knowledge regarding stormwater management in traditional Chinese villages are mostly qualitative studies, and these fail in their evaluation of the functional performance of stormwater management facilities and measures. Therefore, we use the Storm Water Management Model (SWMM) in our quantitative evaluation of stormwater management in Zhuge, a traditional Chinese village, so as to rationally analyze the traditional ecological knowledge regarding stormwater management in traditional Chinese villages. In order to analyze the functions and efficiency of stormwater management facilities such as ponds, canals, and permeable pavement in Zhuge Village, this study sets out four scenarios: the No Pond Scenario (NO-PO), the No Canal Scenario (NO-CO), the No Permeable Pavement Scenario (NO-PP), and the actual Current Scenario (CS). The SWMM is used to simulate and quantitatively analyze the stormwater hydrological processes of the four scenarios in different rainfall return periods. The following conclusions emerged from our evaluation of the approaches used in Zhuge Village: (1) The rainwater regulation system composed of ponds, canals, and permeable pavement can play a dual role in alleviating rainstorm disasters and fully storing rainwater, achieving the flexible allocation of rainwater resources. It can effectively alleviate the problem of uneven time and space of local rainfall in shallow, hilly areas, reflecting the traditional ecological wisdom of residents in adapting to the local natural environment. (2) As a rainwater regulation device, ponds are very effective in storing water and mitigating periods of intense runoff. (3) The main function of canals is to rapidly drain water and balance rainwater resources. (4) The main function of permeable pavement is to increase rainwater infiltration and reduce the peak runoff and runoff. (5) The use of the SWMM proved effective in both quantifying the results as well as elucidating stormwater management strategies.

Diffusion characteristics of surface treatment emulsion in aged asphalt mortar of porous asphalt mixture through SEM/EDS analysis

ABSTRACT Spaying surface treatment (ST) asphalt emulsion can be an effective preventive maintenance method to alleviate the ravelling problem of porous asphalt (PA) pavement. The applied ST emulsion may gradually diffuse in and soften the aged asphalt mortar film in PA, which however still lacks quantitative evidence. This study aims to quantify the diffusion behaviour of new ST emulsion residue in aged asphalt mortar of PA within 28 days of curing. The Scanning Electron Microscopy (SEM) with Energy Dispersive Spectroscopy (EDS) was utilised to capture the spatial distribution of ST emulsion residue within PA under different curing temperatures and durations. Titanium dioxide was selected as a tracer for ST emulsion. Diffusion degree (Dd), derived from the counting of Ti and S elements, was proposed to quantify the diffusion depth of ST residue in aged mortar. It was found that the SEM/EDS is an effective microscopic method to directly monitor the diffusion phenomenon at the mixture scale. The diffusion rate at 60oC is about 5 times faster than that at 25oC, indicating that spraying ST emulsion in hot weather can improve its diffusion efficiency. Besides, the existence of fine aggregates in mortar may increase the diffusion path due to the hindrance effect.

Discovering the Perception Differences of Stakeholders on the Sustainable and Innovative Stormwater Management Practices

The overarching aim of the present work is to explore the perception differences of stakeholders, i.e., municipalities (MN), water administrations (WS), non-governmental organizations (NGO), and universities (UN), playing vital roles in the decision mechanisms regarding one of the sustainable flood mitigation techniques, i.e., low impact development (LID) practices. As being rewarding alternative to conventional drainage techniques, four different LID strategies, i.e., green roof (GR), bioretention cells (BC), permeable pavement (PP), and infiltration trench (IT), and three of their combinations were adopted to the densely urbanized Ayamama River basin, Istanbul, Turkey. The performances of the LIDs were comprehensively evaluated based on three pillars of sustainability (i.e., social, economic, and environmental) using a hybrid multi-criteria decision-making (MCDM) framework containing the implementation of fuzzy analytical hierarchy process (fuzzy AHP) and the VIKOR (VIse KriterijumsaOptimiz acija I Kompromisno Resenje) for finding the weights of constraining criteria and prioritizing the LID scenarios, respectively. The major outcomes of this research showed that experts from MN, WS, and UN put forward the environmental dimension of sustainability, whereas respondents from NGO concentrated on the social aspect. Furthermore, MN and WS highlighted initial investment cost as the most determining criterion in optimal LID selection. On the other hand, criteria weights regarding the judgments of the experts attended from NGO revealed the significance of community resistance in specifying the optimal LID practices, while aesthetic appearance was the major concern of the academia. Hence, the present study, as an initial attempt, enabled critical standpoints for discovering perceptions of stakeholders.

Combining Pocket Parks with Ecological Rainwater Management Techniques in High-Density Urban Environments

In this paper, the benefits of combining pocket parks with Sustainable Drainage Systems (SuDS) in densely built urban areas are demonstrated, through an application proposal in a medium to low-income neighborhood of the historical center of Thessaloniki, Greece. After an outline of the urbanization impact upon rainwater management, the features of the proposed site are presented, in particular those related to rainwater runoff (e.g., rather large ground slope, narrow sidewalks), which result in considerable nuisance, even during medium intensity rainfall events. The choice of the SuDS components, namely a small-scale rain garden and a permeable pavement zone is explained next. Then, the basic design details of the proposed rain garden are given, including the form of the inlet structures and a list of plants, suitable for the climatic conditions of many North Mediterranean regions. The role and the features of the permeable pavement zone are also discussed and some ideas for the urban equipment required to upgrade the park are presented. A preliminary estimate of the cost for the construction of the rainwater management works and for upgrading the available lot to a pocket park is also included. Compared to the cost of sewer pipe network reconstruction, it can be concluded that the proposed solution is cost-efficient, even without considering aesthetic and social benefits. Moreover, it allows for stepwise construction, based on the available funds.

A Comparative Study of Porous Asphalt Strength Reinforced with Expanded Polystyrene Foam and Ash-Based Fillers: Cantabro Test Findings

This research sought to evaluate the effects of incorporating extruded polystyrene (XPS) into porous asphalt mixtures and to understand the role of various filler combinations, specifically coconut shell ash (CSA) and rice husk ash (RHA), on the mixture’s performance. For this purpose, asphalt mixtures were subjected to the Cantabro test under both unconditioned and conditioned modes. Mixtures were treated with XPS in varying proportions ranging from 7% to 11%. The filler combinations were further varied, with mixtures containing 7% XPS showing Cantabro loss results of 35.71% for 1SD:3CSA and 43.44% for 1SD:1RHA, and those with 11% XPS demonstrating significant reductions to 19.24% and 18.93% respectively. The findings indicate that introducing XPS notably enhances the mixture’s stability and resistance to abrasion and disintegration. CSA-based mixtures generally showcased a more pronounced positive effect on stability than those with RHA. When subjected to moisture conditioning, all mixtures exhibited an increased sensitivity, though the 1SD:1RHA mixture showed the highest resilience against moisture damage. In conclusion, integrating XPS in porous asphalt mixtures can lead to significant performance improvements. The choice of filler, its proportion, and its interaction with XPS are critical factors in determining the mixture’s overall performance, especially its resistance to moisture and abrasion.

Experimental study of the effect of high-strength clogging-resistant permeable pavement (CRP) on the runoff using a rainfall simulator.

Permeable pavements play an effective role in reducing runoff by decreasing the impermeable area. But, conventional permeable pavements suffer disadvantages such as low resistance. To address this, the 'high-strength clogging-resistant permeable pavement (CRP)' has been developed. The present study aimed to evaluate the performance of the CRP model with varying percentages of coverage (A) of 25, 50, and 100%, slopes (S) of 1, 3, and 5%, as well as rainfall intensities (I) of 45, 55, 70, 90, 170, and 200 mm/h. Based on the results, there was an increase in A from 50 to 100% at I = 90 mm/h, decreased runoff coefficient (C) of 18, 15, and 13% at S of 1, 3, and 5%, respectively. At the same I, increasing S from 1 to 5% increased the C coefficient in A of 0, 25, 50, and 100% by 3, 31, 32, and 39%, respectively. Due to the ever-increasing urbanization and the subsequent increase in impervious areas, the risk of severe floods has greatly increased. Therefore, providing solutions such as the CRP model can help reduce flood risks in urban areas. The findings of this research can be used as a guide in the design of high-strength clogging-resistant permeable pavements in urban areas.

Impact of rainfall on the thermal performance of geothermal permeable pavement systems

Geothermal permeable pavement (GPP) systems are a nascent type of energy geo-structures. GPP combine ground-source heat pump (GSHP) systems with permeable pavements to enable the additional functionality of heating and cooling, through energy harvesting using roads alongside existing drainage controls. GPP thermal performance is relatively unknown, hence, this research focuses on the development of a detailed 3D finite element (FE) model that considers local thermal non-equilibrium (LTNE) for exploring the influence of rainfall infiltration on the thermal performance of GPPs. The 3D numerical model was successfully validated and was used to evaluate the short-term thermal response of GPPs during rainfall events in both cooling (summer) and heating (winter) demand conditions. Furthermore, the diurnal rainfall effects and the influence of raindrop temperature and rainfall duration on GPPs were also examined. Results show that rainfall can have significant impacts on the thermal performance of GPPs and the raindrop temperature is an important parameter in yield predictions. Compared to no-rainfall events, the GSHP system fluid temperature during rainfall can differ by up to 19% when in the cooling operation model (air conditioning) and 63% in heating mode. These results indicate the significantly better performance of GPPs than impervious geothermal pavements, depending on the climatic conditions and end-use.

Recycling of plastic waste in porous asphalt pavement: Engineering, environmental, and economic implications

With the rapid rise in the number of plastic products, recycling plastic waste has become a crucial challenge worldwide. Recycling plastic waste in asphalt pavement has emerged as an alternative solution to traditional mechanical and chemical recycling methods. However, there has been limited research into the comprehensive exploration of using plastic waste in porous asphalt pavement, an ecologically sustainable and safer form of pavement. This study aims to assess whether recycling plastic in porous asphalt pavement through wet process is a sustainable strategy by analyzing its engineering, environmental, and economic implications. The engineering properties of plastic-porous asphalt pavement, including rutting resistance, moisture sensitivity, abrasion resistance, cracking susceptibility, and fatigue life, were evaluated to verify if this strategy can provide adequate performance and durability. In addition, this study also examines the potential impacts of plastic waste on the aquatic environment due to the crucial significance of water resources. Moreover, a life cycle cost analysis (LCCA) was performed to determine the economic benefits of incorporating plastic waste into porous asphalt pavement. The results indicate that the incorporation of plastic waste can enhance the rutting and stripping resistance of porous asphalt pavement, but excessive use of plastic waste may reduce its abrasion resistance. Furthermore, recycling plastic waste in porous asphalt pavement does not contribute to aquatic environmental pollution, and the appropriate use of plastic waste has the potential to generate economic benefits. Overall, this study proves that recycling plastic waste in porous asphalt pavement is a sustainable engineering solution to address the plastic waste crisis and create a circular economy for plastics.

Field temperature performances of in-use permeable sidewalks and asphalt vehicle roads and the potential impacts on apparent temperature and land surface temperature.

Permeable pavements help reduce surface temperatures and have been widely implemented in urban areas. This study utilized an in-use permeable pavement sidewalk in front of a mass rapid transit station in the Taipei city center of Taiwan to determine the actual pavement surface temperature performance. A neighboring asphalt road and impervious pavement were also monitored. With a full year of continuous monitoring, the results showed that the temperature of permeable pavement was 3.7°C lower than that of impervious pavement and 4.5°C lower than that of asphalt pavement in the hot season. The frequent rainfall in spring resulted in the smallest temperature differences between the different pavement types. The cooling effects of permeable pavement differed at the different air temperatures. At air temperatures lower than 15 °C, the differences among pavement surface temperatures were noticeable. However, when the air temperature was higher than 35 °C, the surface temperature of permeable pavement was not different from that of impervious pavement and was greater than 55 °C. Field observations were carried out to determine the effects on the apparent temperature and the future surface temperature of climate change scenarios. The results showed that permeable pavement could reduce the average apparent temperature to near the air temperature, and asphalt pavement could increase the apparent temperature by 1.2°C, assuming that the pavement temperature completely affects the air temperature. With the good prediction ability of the machine learning approach and 15 environmental factors, the preliminary prediction showed the projected surface temperature change in Taipei city in 2033. In the worst-case scenario, the average impervious pavement temperature is as high as 39.12°C, whereas the average permeable pavement temperature is 32.50°C.

Investigation of energy-based interlayer debonding of open-graded friction course pavement under mode I fracture test

Layer bonding performance is essential for ensuring the longevity of open-graded friction course (OGFC) pavements. This study examined the interlayer bonding efficacy between OGFC and the underlying layer, considering variations in underlying layer types and the quantity of tack coat applied. To assess the bonding characteristics, three-point bending tests were performed at temperatures of 0 ℃ and 25 ℃. Parameters such as bonding stiffness, stress intensity factor, equivalent stress intensity factor, and energy parameters were determined to elucidate the fracture behavior between OGFC layers and their supporting layers. The total fracture energy (GF) was segmented into three components: plastic dissipation energy (Ud), elastic stored energy (Ue), and surface energy (Up), providing a comprehensive analysis of the energy dynamics during fracture. Results showed that at 0 ℃, the maximum bonding stiffnesses of OGFC-A and OGFC-B were obtained when the coat application contents were 1.0 kg/m2 and 0.5 kg/m2, respectively. With the increase of temperature, the bonding stiffness decreased significantly. At 0 ℃, the maximum value of KIC of OGFC-A was higher than that of OGFC-B by 7.1 %, which was attributed to the rougher surface of mixture A in terms of texture depth, average roughness and fractal dimension. At 0 ℃ and 25 ℃, the optimal tack coat application contents for fracture energy were 1.0 kg/m2 and 0.5 kg/m2 for OGFC-A and OGFC-B, respectively. At 0 ℃, the maximum value of GF of OGFC-B was higher than that of OGFC-A by 54.0 %; while at 25 ℃, the maximum value of GF of OGFC-B was lower than that of OGFC-A by 16.7 %. At both 0 ℃ and 25 ℃, the maximum values of Ud + Ue of OGFC-B were larger than that of OGFC-A, indicating that at both 0 ℃ and 25 ℃, the rougher interface of the underlying layer (mixture A) would not require more energy to initiate a crack. At 0 ℃, then energy required for crack propagation of OGFC-B was larger than that of OGFC-A; while at 25 ℃, opposite results were obtained, indicating a rougher interface (mixture A) helped delay the crack propagation. Temperature, underlying layer type, and tack coat affected the proportions of Ud, Ue and Up.

Investigation of material composition, design, and performance of open-graded asphalt mixtures for semi-flexible pavement: A comprehensive experimental study

The primary goal of this study is the design and construction of semi-flexible pavement (SFP) mixture in accordance with the engineering and mechanical criteria. This study involves the use of a range of gradation curves, air void contents, cellulose and synthesized fibers, and neat and modified asphalt binders to prepare the open-graded asphalt (OGA) mixtures. To analyze the characteristics of these mixtures, a variety of test, namely binder drainage, semi-circular bending (SCB), Cantabro, wheel tracking, indirect tensile strength (ITS), and permeability tests were conducted. Additionally, to analyze the prepared grouting material, flexural strength, compressive strength, and fluidity tests were conducted. In the final stage, SFP was compared to HMA in terms of engineering characteristics and performance. According to the results, SFP was more resistant to skid, rutting, fire, and moisture damage, while HMA had a better performance in fracture tests, including SCB test. According to the results of the mechanical performance tests conducted on OGA mixtures, the highest and lowest values for air void content to achieve the highest mechanical performance level were 30%–35% and 25%, respectively. Also, based on the laboratory results, it was determined that the required void ratio for constructing OGA mixtures was 24%–26% based on the bitumen type and fibers amount in the mixture. Finally, SFP mixture can be regarded as a viable alternative to common pavements thanks to its high resistance to rutting and moisture damage, long freezing-thawing fatigue life, and adequate fire and skid resistance.

3D modelling of the hydraulic performance of open-graded asphalt using the DEM and CFD methods

In this study, we propose a modelling approach that combines computational fluid dynamics (CFD) and the discrete element method (DEM) to simulate the hydraulic performance of three-dimensional (3D) porous asphalt (PA) specimens. Initially, realistic aggregate appearances are captured through the image analysis technique. This information is then transferred to DEM software for the reconstruction of pore structure with distinct aggregate shapes following the real particle size distribution (PSD) as identified by local construction standards. The pore structure, reproduced via DEM, is used as input for CFD simulation to assess the hydraulic performance. To capture the dynamic of water motion simulation, the multiphase model, volume of fluid method (VOF), within CFD is applied to track and predict the interactions between different material phases, and the effect of porous structure to the hydraulic behaviour and performance. Results of numerical simulations indicate that PA samples with higher total porosity (air voids) have better pore connectivity and more effective porosity. For samples with the total porosity of 20%, the difference between the total porosity and the effective porosity was 14.8%; while a much lower difference of 8.3% was found for the higher porosity (25%) specimen. Compared with effective porosity, the reduction in active porosity reaches 58.8% in deeper layers for the sample at 20% total porosity, and only 32.2% for the sample at 25% total porosity. Overall, the results show that there is about a 4.57 times difference in hydraulic performance represented by mass flow rate among PA samples with 5% total porosity difference.

Shear strength parameters for porous asphalt mixtures: From macro to meso

The shear strength of asphalt mixtures significantly influences the rut resistance of flexible pavements. Existing methods predominantly address macroscopic aspects, failing to unveil the underlying mechanisms. Moreover, experimental determination of shear strength parameters is time-consuming, but there is a lack of simple prediction methods. This study explores correlations between macroscopic parameters (friction angle and cohesion) and key mesoscopic shear-related factors in Porous Asphalt Mixtures (PAMs) using multiscale triaxial compressive tests, dynamic shear rheometer tests, and sessile drop tests. The research reveals that PAM is influenced not only by aggregate interlock but also by stiff mastic, resulting in a reduced friction angle at a lower temperature. Regression analyses establish a prediction formula for PAMs, incorporating the friction angle of the aggregate skeleton and the complex modulus of the mastic. A correlation function, inspired by Griffith's fracture theory, was also proposed to link PAM's cohesion with the complex modulus and the work of cohesion of mastic, and the friction angle of PAMs. Predictions for PAM's friction angle and cohesion align well with macro-level experimental results, with all the coefficients of determination of over 0.94. These findings enhance the understanding of asphalt mixture shear strength formation and enable shear-resistance optimisation from meso-level.

Evaluation of a hybrid-polymer pervious mortar and optimization of its mix design

The utilization of permeable pavement has notably increased in urban areas. However, the conventional bonding layer composed of ordinary mortar or coarse sand can lead to challenges such as easy-loosening and a pseudo-permeable effect. To tackle this problem, this study utilized a hybrid polymer additive (HPA) to develop a novel hybrid-polymer pervious mortar (HPPM). An orthogonal experiment with the Composite Scoring Method (CSM) was conducted to determine the optimal mix design for HPPM, and the effect of the HPA content water-to-binder (W/B) ratio on the mechanical and bonding properties was analyzed. The CSM result revealed that the HPA content presented a higher significant impact than the W/B ratio, and the optimal combination was B3A2 - HPA content of 6 % (B3) and W/B of 0.3 (A2). Under this optimal combination, HPPM was able to enhance the compressive strength, flexural strength, tensile bond strength, and workability compared with the pervious mortar without HPA. Simultaneously, this study revealed that HPPM exhibited a higher ratio of interconnect voids compared to ordinary mortar, and demonstrated HPPM was able to achieve a good permeable function. In addition, according to the life-cycle cost and eco-efficiency analysis, the cost of permeable pavement using HPPM was lower than that of ordinary mortar, while HPPM represented savings in resource consumption and in energy consumption. Consequently, these results demonstrated the feasibility of using HPPM as an eco-friendly alternative to mitigate the pseudo-permeable issue of permeable pavement.

Research on skid-resistance durability of high viscosity modified asphalt mixture by accelerated abrasion test

To evaluate influence of external environment and material composition on skid-resistance durability of high viscosity modified asphalt (HVMA) mixture, the accelerated abrasion test was selected to simulate decay of skid resistance for asphalt mixture by setting different test conditions. The influence of aggregate gradation, asphalt type, ambient humidity and overload on skid-resistance durability of asphalt mixture was discussed, and the significant effect of selected factors on skid-resistance durability of asphalt mixture was revealed. The results show that the skid-resistance durability of SMA-13 (Stone Mastic Asphalt) mixture is better than OGFC-13(Open Graded Friction Course) and PA-13 (Porous Asphalt) mixture under different conditions, and attenuation rate of different indexes of SMA-13 mixture is 1.6–2.2% and 0.8–2.1% lower than compared with OGFC-13 and PA-13 mixture. The attenuation rate of texture depth for asphalt mixture is closely related to aggregate gradation and asphalt, but the attenuation rate of british pendulum number for asphalt mixture with the same mineral aggregate is only significantly affected by the asphalt. The skid resistance of SMA-13 and PA-13 mixture is improved slightly by addition of high viscosity modified asphalt. The attenuation rate of texture depth of SMA-13 and PA-13 mixture with HVMA is reduced about 0.6–3.0% and 2.2–4.2% than SBS modified asphalt, but the attenuation rate of british pendulum number of above mixtures is increased about 1.2–1.6% and 0.3–1.7%. The skid-resistance durability of asphalt mixture with TPS (TAFPACK-Super) and SINOTPS high viscosity agent is better than HVA (High viscosity additive). The skid-resistance durability of asphalt mixture based on texture depth is improved under wet condition. However, the skid-resistance durability of asphalt mixture for british pendulum number gets worse due to water intrusion. The skid-resistance durability of asphalt mixture is rapidly decreased under overload condition. The influence of overload and SBS modified asphalt on skid-resistance durability of asphalt mixture is higher than ambient humidity and HVMA. This paper will provide foundation for high viscosity modified asphalt applied in asphalt pavement.

ANÁLISE CRÍTICA DAS TÉCNICAS COMPENSATÓRIAS DE DRENAGEM URBANA

The following research presents compensatory techniques for urban drainage, through a literature review. Among the compensatory methods, four different techniques were chosen: permeable pavement, green roof, rain garden and retention basin, to present their operating principles and environmental benefits, compare the positive environmental impacts of compensatory techniques in comparison with traditional approaches to urban drainage and analyze case studies of different cities that have successfully implemented the compensatory techniques under study. The main objective of the study was achieved, as it can be clearly understood that the techniques under study contributed to the reduction of floods, reducing the impacts caused by them.

Laboratory performance evaluation of porous asphalt mixture containing recycled concrete aggregate and fly ash

This study performed laboratory experiments to evaluate the performance of porous asphalt mixtures (PAMs) containing recycled concrete aggregate (RCA). One open aggregate gradation with Class C fly ash as the filler, granite aggregate, two binder types (PG 67–22 and PG 76–22), and four RCA contents (0%, 10%, 20%, and 30% by mass of aggregates in the sieve size range of 4.75 to 9.5 mm) were included in the experiments. The mixture properties evaluated include permeability and air-void content, Marshall stability and flow, indirect tensile strength, moisture susceptibility, Cantabro abrasion loss, macrotexture, and sound absorption coefficient. The study found that using a blend of granite and RCA in a PAM led to better performance in terms of indirect tensile strength, stiffness, moisture resistance, and resistance to raveling. This was particularly confirmed for PAMs with an unmodified PG 67–22 binder. The mixture that contained 30% RCA performed the most satisfactorily, with an indirect tensile strength of 0.81 MPa and a Marshall stability of 23 kN at 25 °C. These values were 37.5% and 15%, respectively, higher than the control mixture. Based on these results, the study recommends the use of 30% RCA in PAMs for the friction course of a highway pavement or the porous surface of a porous pavement.