Permeable Road Research Articles

Field experiment on a vegetation-wicking geotextile-reinforced base for a permeable sidewalk

Wicking geotextiles have proven effective in reducing water content in road bases under both saturated and unsaturated conditions, thereby increasing granular base strength and mitigating moisture-related damage to the pavement. Despite their effectiveness in paved roads, the use of wicking geotextiles in permeable road and sidewalk, particularly in areas requiring robust drainage such as sponge cities, is not well explored. In “sponge city” roads, moisture content fluctuations and subsequent damage to the structure often cause concern, and the wicking geotextile’s drainage could be a potential solution. Therefore, this study aims to investigate and quantify the effectiveness of wicking geotextiles in reducing the moisture content and improving the resilient modulus of permeable sidewalk base layers. The moisture contents of unstabilized and one-directional wicking geotextile- and two-directional wicking geotextile-stabilized bases under permeable paving bricks were monitored with an interval of 7–10 days for over a year. An analytical approach to reconstruct daily moisture content in the base layer was proposed based on the simulated rainfall saturation test. This approach further assesses the enhancements in resilient modulus due to the drainage capabilities of wicking geotextiles. The experimental results indicated that the two-directional wicking geotextile outperforms its one-directional counterpart and both wicking geotextiles outperformed the control condition in terms of drainage efficiency. By reconstructing the daily moisture content and utilizing the relative damage model, the two-directional wicking geotextile significantly improved the annual equivalent resilient modulus of the base layer under permeable paving bricks.

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.

Experimental Study on the Mechanical Properties and Permeability of Cement-Stabilized Permeable Recycle Aggregate Materials

This paper designed cement-stabilized permeable road subgrade materials. Construction demolition waste with recycled aggregate replaced natural aggregate in cement-stabilized materials to utilize recycled resources for construction solid waste. This paper tests the compressive strength, water permeability, bending strength, and compressive resilience modulus of cement-stabilized permeable recycled aggregate materials under different cementitious additive ratios. The results show that at a recycled aggregate proportion of 30% in cement-stabilized permeable recycled aggregate material, the 7-d unconfined compressive strength exceeds 3.5 MPa, and the permeability coefficient surpasses 3.5 mm/s, which can meet the roadbed requirements in China. The incorporation of recycled aggregates significantly reduces the mechanical properties and water permeability of cement-stabilized permeable recycled aggregate materials, while cementitious additives improve the mechanical properties. Specifically, red brick, old concrete, and ceramics in recycled aggregates weaken the mechanical properties of the skeleton structure of cement-stabilized permeable recycled aggregate materials, and the compressive strength, bending strength, and compressive resilience modulus decrease with the recycled aggregate content. Cementitious additives can fill the micro-pores of the interface transition zone of cement-stabilized permeable recycled aggregate materials to improve the cementation strength between aggregates.

Case Study of Stormwater Control by Permeable Road in Commercial Centre under Equatorial Climate

This paper describes the investigation into stormwater control measures of a 3,425 m2 commercial centre with 61% of the total areas which were tarred surfaces. Targeting these surfaces, permeable roads of various surface areas from 10 to 34% of the total areas were modelled using Storm Water Management Model version 5.0. Testing the permeable roads for very-short duration storms ranging from 5 to 15 minutes, the study found that the catchment area contributing water for detention purposes played a major role in stormwater control. Other than that, the orifice outlet attached to the storage facility was dominant in determining the flow than the storage depth.

Testing the Concept of Mitigating Urban Flooding with Permeable Road: Case Study of Tong Wei Tah Street, Kuching City, Sarawak, Malaysia

This paper describes the investigation of permeable road as a mitigation measure for urban flooding. The study involves the reconstruction of a historical case of inundation, namely the 11 December 2019 flood event along the Tong Wei Tah Street in Greater Kuching City, Sarawak, Malaysia. The Storm Water Management Model version 5.0 was used as the platform to describe the flooding at the selected site and the functionality of permeable road to alleviate flooding. A permeable road with a dimension of 200 m long, 6 m wide and 1 m deep was simulated along the whole stretch of Tong Wei Tah Street. The model results show that flooding was caused by a backwater effect in the drainage system. Models predicted 0.1 to 0.5 m flood depths which matched the observed 0.3 m flood depth account of a local resident. The permeable road exhibited capability to absorb all the out-of-drain floodwaters, leaving no water due to the 11 December 2019 flood on the street. Modelling efforts demonstrated that the floodwater hydrographs in the drain rose and fell within 7 h, while the underground storage, filled and drained within 13 h. Moreover, the storage of permeable road was found to fill up to 75 %, reserving the unfilled 25 % for adverse weathers.
 HIGHLIGHTS
 
 It was demonstrated in the case study of Tong Wei Tah Street that waterproof tarred road could be changed to permeable road that consists of permeable pavement layer and underground storage as urban flood mitigation strategy
 Through modelling efforts of a flooding event along Tong Wei Tah Street and its associated drainage systems, any spill of running water from the urban drains could be directed to the permeable road for temporary storage and conveyance
 It was found that floodwater on the road could be adsorbed by the permeable road structure itself, and as such, lessening the hydraulic burden of urban drains
 
 GRAPHICAL ABSTRACT

ENVIRONMENTAL ASSESSMENT OF STORMPAV GREEN PAVEMENT FOR STORMWATER MANAGEMENT

This study evaluates the stormwater management potential of a green pavement technology for permeable road pavement with subsurface micro-detention storage (StormPav) from a water quality perspective. The system provides integration of permeable pavement with hollow spaces to attenuate peak discharge with design installation using precast products. The environmental assessment was gathered from field experiments to assess the water quality, mosquito breeding capability and infiltration rate in the StormPav. The water quality parameters were determined to assess environmental benefits, which are one of the components of sustainable development. The parameters consist of total suspended solids, pH and alkalinity and they showed identical results to other permeable pavement types. Larvae development was found as early as eight days in stagnant water in the cylindrical hollow section of StormPav. However, the StormPav showed a high permeability rate within 122.45 mm/hr to 168.12 mm/hr at subgrade soil of HSG A soils group with no stagnant water retained in the void section in less than two hours, which nullified the required retention time for larvae development. Hence, StormPav displayed a significant benefit in terms of environmental concern for a sustainable design invention in stormwater management with the presence of subsurface detention storage.

A Study on the Design Depth of Permeable Road Pavement through Dynamic Load Experiment.

This study investigated vertical strain and stress through a dynamic load experiment at the testing area of Ke-Da Road, Pingtung, Taiwan. A thirty-five-ton truck was moved at constant speeds of 40, 60, and 80 km/h to simulate heavy load conditions to study the mechanical variations. From the results, it was found that the strain and stress curves of the permeable road pavement showed asymmetry due to the viscoelastic property of the open-grade friction course. The results showed that vertical strains and vertical stresses of permeable road pavement were greatly affected by the axle configuration and the change in traffic speed. Furthermore, to propose the design thickness of a permeable road pavement, the pavement strain and stress were modelled with respect to depth using regression based on these collected data. According to the stress regression models and considering the construction uncertainty, the recommend design depth of a permeable pavement is 30 cm. The findings of this study would be helpful in determining the permeable road pavement depth when subjected to heavy traffic load, and the material combination of open-graded friction concrete, porous asphalt concrete, and permeable cement concrete was proposed in this study during the design period.

Svojstva poroznih asfaltnih mješavina s etilen propilen-dienskim monomerom

Porous asphalt pavements are environmentally friendly permeable road pavements. There is a need to improve the strength performance of porous asphalt mixtures. Waste Ethylene Propylene Diene Monomer (EPDM) rubber modification of porous asphalt mixtures is investigated in this study. The mixture was initially designed for the selected mix aggregate gradation. Waste EPDM rubber scraps were replaced with filler materials at the rate of 2 % and 4 % of the total aggregate weight. Performance tests were conducted on test specimens. The EPDM rubber scraps improved the elasticity and strength properties of PA mixtures.

A Study on Heat Storage and Dissipation Efficiency at Permeable Road Pavements.

The main contributing factor of the urban heat island (UHI) effect is caused by daytime heating. Traditional pavements in cities aggravate the UHI effect due to their heat storage and volumetric heat capacity. In order to alleviate UHI, this study aims to understand the heating and dissipating process of different types of permeable road pavements. The Ke Da Road in Pingtung County of Taiwan has a permeable pavement materials experiment zone with two different section configurations which were named as section I and section II for semi-permeable pavement and fully permeable pavement, respectively. The temperature sensors were installed during construction at the depths of the surface course (0 cm and 5 cm), base course (30 cm and 55 cm) and subgrade (70 cm) to monitor the temperature variations in the permeable road pavements. Hourly temperature and weather station data in January and June 2017 were collected for analysis. Based on these collected data, heat storage and dissipation efficiencies with respect to depth have been modelled by using multi regression for the two studied pavement types. It is found that the fully permeable pavement has higher heat storage and heat dissipation efficiencies than semi-permeable pavement in winter and summer monitoring period. By observing the regressed model, it is found that the slope of the model lines are almost flat after the depth of 30 cm. Thus, from the view point of UHI, one can conclude that the reasonable design depth of permeable road pavement could be 30 cm.

Evaluation of Siltation Degree of Permeable Asphalt Pavement and Detection of Noise Reduction Degree

This study mainly uses PFC (particle follow code) to simulate the void characteristics of permeable asphalt mixture, and uses these to simulate the silting process. Then, a tire drop test was used to evaluate the noise reduction performance of permeable asphalt concrete. Finally, a self-made ring rutting test machine was used to simulate the silting process. Through experiments, the following conclusions were obtained: 1. The critical size of the sludge particle size is 0.3 mm–0.6 mm. 2. The quality of the water-permeable asphalt concrete specimens increased by 13% before and after silting, and the porosity of the specimens finally decreased from about 20% to about 8%. The water-permeable function only retained less than 20% of the original, and the water-permeable function was basically lost. 3. By measuring the road noise detection, it was found that the road noise is directly proportional to the degree of blockage of the permeable road. Compared with the original road with a perfect permeable function, the road noise of the completely blocked road increased by about 4 decibels. This study reveals the silting process of permeable asphalt mixture and the key particle size of the silt, which is of great significance for the detection, cleaning and maintenance of permeable asphalt pavements.

Testing the Concept of Mitigating Overflowing Urban Drain with Permeable Road

Testing the Concept of Mitigating Overflowing Urban Drain with Permeable Road

Hydrological impact assessment on permeable road pavement with subsurface precast micro‐detention pond

AbstractThe purpose of this paper is to study stormwater management potential of new permeable pavement with subsurface micro‐detention storage (PPDS) at low‐speed residential suburban area. The main features incorporated permeable pavement of a hollow micro cylinder precast structure with solid hexagon precast concrete as top and bottom covers. The purpose of hollow micro detention design is for rainwater holding and void between the sets is for self‐drying through the side and bottom seepage during rain. The hydrological parameters were obtained from laboratory rainfall simulator experiment. The performance was evaluated via simulation with Storm Water Management Model (SWMM). The outcomes from the physical model matched well with SWMM. A case study was then developed to assess the hydrological impact of PPDS with the existing condition and other types of permeable pavements. Significant variance was observed, where PPDS displayed its best hydrological performances for stormwater management with the presence of subsurface detention storage.

Permeability Properties of Crushed Stone Aggregates in Bedding Course of Urban Permeable Roads: An Experimental Study

Crushed stone is the most common material for use in the aggregate of bedding course. The aggregate for the bedding course of permeable roads needs to not only meet the requirements of basic mechanical properties but also ensure permeability and structural stability. This work analyzed permeability under extreme rainfall conditions and the particle mass loss during permeation and then investigated the stability of crushed stone aggregate and examined the optimal gradation and compaction levels of the crushed stone aggregate in engineering applications. It shows that (1) the permeation process included two phases, and the change of permeation velocity mainly occurred in the first phase. The permeation velocity of samples with different gradations at different compaction levels showed a stepwise change in its order of magnitude. (2) The change in permeability coincided with the change in flowrate, most probably because the sudden change of the flow altered the permeability of the sample. Factors such as gradation, compaction, and the randomness of particles arrangement in the crushed stone during sample charging all affected the permeability of the sample. (3) During the permeation process, the mass loss decreased with rising gradation. The gradation and compaction had strong influence on particle mass loss. Therefore, ensuring the structural stability of permeable road necessitates careful selection of the gradation and compaction for the crushed stone aggregate. It is recommended to use the crushed stone sample with a gradation of n = 0.7 and a compaction level of no greater than 20 mm for the aggregate of the bedding course.

Properties of Modified High Permeable Concrete with a Crumb Rubber

Background: High permeable concrete is designed with high porosity, which allows water to pass through it. By considering this ability, it has been widely used for various applications including high permeable road pavement. However, to fully adopt highly permeable road pavement technology is challenging due to high cost and maintenance, besides the present engineers and contractors have insufficient expertise and experience with this technology. Henceforth, the high porosity property is highly favorable for road curb applications especially in the tropical region like Malaysia with high rainfall intensity. Objective: This paper aimed to determine the properties of the concrete experimentally, and propose the optimum mix design of high permeable concrete for road curb. Methods: The flow value and setting time of the cement paste were investigated. Next, the effects of the modified high permeable concrete with varying amount of crumb rubber on compressive strength, permeability and void ratio were also investigated. Results and Conclusion: Results have revealed that the workability of the cement paste increases when the water-binder ratio and the amount of fly ash increase. Meanwhile, an increasing amount of cement ratio and crumb rubber lowers the flow value and consequently leads to lower void ratio and permeability. Besides, it has been found that the higher the compressive strength, the lower the void ratio and permeability of the concrete. The research findings support that using an optimum amount of cement replacement with crumb rubber as an additive may increase the performance a high permeable concrete. Herein, the results indicate that the mix design of the concrete studied has the potential to be applied onto the road curb.

Application of StormPav Green Pavement System in a Government Buildings Redevelopment Scheme

StormPav Green Pavement System is a non-commercialized permeable road with a function of stormwater detention. This paper demonstrates the application of the R&D product in part of a 14,000 m2 government building complex as a new feature of sustainable drainage system. To assess its stormwater impacts to the project site, two software are utilized to analyze the stormwater flow processes when merely 10% of the project area is incorporated with StormPav. Firstly, Storm Water Management Model (SWMM) is used to simulate the project-wide stormwater flow, in which reductions between 22% - 6% in terms of peak flow rates are predicted compared to conventional drains when subjected to 5 – 180 minutes of 10-year Average Recurrent Interval (ARI) design rainfall. Secondly, SolidWorks Flow Simulation (SWFS) simulates the detailed flow processes within the StormPav system, in which it is found 0.5 – 1.3 m/s of velocities are predicted around the inlets and outlet that conform to the local stormwater management standard. Besides, SWFS allows visualization of velocity and streamline profiles across the StormPav system that conventional SWMM could not provide.

Design Factors and Procedure for Hydrological Design of Permeable Road Systems

Design Factors and Procedure for Hydrological Design of Permeable Road Systems

Hydraulic properties of polyurethane-bound permeable pavement materials considering unsaturated flow

Constant urban and infrastructural growth leads to increased sealing of areas in municipal areas. This surface sealing results in distortions of the natural water cycle, which again can lead to noticeable changes in the natural ecosystem. To counteract the effects of surface sealing, innovative permeable road structures provide a promising environment-friendly opportunity. An innovative highly permeable road surface material based on alternative binders using polyurethane (PU) to replace the conventionally used bituminous binders has been developed in the course of an ongoing research project. It is intended that the high permeability of the road’s surface material and underlying support layers leads to a quick drainage through the road construction down to the subsoil. The aim of this study is to understand and quantify the relevant hydraulic properties of PU-bound road surface material, i. e. the water retention behaviour and the hydraulic conductivity in saturated and unsaturated states. A predictive model to determine the surface material’s water retention behaviour was used as a first estimation and very low air entry values were observed. Results from laboratory experiments on the material’s saturated hydraulic conductivity as well as the water retention behaviour in the low suction range are presented. Additionally, empirical hydraulic models to describe the retention behaviour and models for the saturated and unsaturated hydraulic conductivities are outlined and applied.

Simulation study on effect of permeable pavement on reducing flood risk of urban runoff

Permeable pavement is part of the low impact development (LID) measurement, which can decrease urban surface runoff coefficient and flood peak flow. In this paper, a two-way, six-lane road in Nanjing was selected as the study area. Storm water management model (SWMM) was used to simulate the effect of different pavement structures (drainage surface, permeable pavement and permeable road) under different rainfall conditions on reducing surface runoff and controlling urban stormwater. The simulation results show that the drainage surface can reduce part of surface runoff, but it has no influence on the reduction and hysteresis of flood peak. The permeable pavement can reduce part of surface runoff and flood peak and can delay peak time. The permeable road has better effect on reducing runoff coefficient and flood peak, which can effectively reduce the pressure of urban drainage and reduce the risk of stormwater flood.

Modelling of Surface Permeation in Multiple-Orifice Permeable Road

A patent-pending StormPav green pavement is introduced here as a form of permeable road, in which the system employed precast concrete pieces as modular units. The pavement layer consists of hexagonal plates with each a service inlet to drain water. This study is exploring the water draining capability or technically surface permeation of these service inlets. Virtual and physical modelling are performed to investigate the service inlets as multiple orifices to permeate surface water of the said permeable road. Both modelling efforts have deduced that the permeable road has 18,000 – 24,000 mm/hr of permeation rate when subjected to a 5-minute red-alert storm (>60mm/hr of intensity). It implies that StormPav green pavement has superior surface permeation against the forming of water ponding and flash flood on roads.

Augmenting Drainage System in the Old Town of Kuching, Sarawak, Malaysia

Padungan, one of the busiest business districts within Kuching City has been facing difficulties due to its age and inability to manage urban runoff. To sustain its historical heritage value without compromising the beauty and ability to discharge urban runoff, environmental needs have called for a change in urban stormwater management. The main objective of this study is to incorporate StormPav Green Pavement along the backstreet of Padungan and to investigate the effectiveness of the permeable road. The methodology used in this study is by means of computer modelling using Storm Water Management Model (SWMM). There are two models built, simulating conditions as (a) current drainage system facility; (b) implementing StormPav Green Pavement along the back of Padungan Street for the purpose of accommodating runoff from the whole two rows of buildings. From the analysis of modelling scenes, implementing the permeable road is a preferable solution as it encompasses both the present and future needs into the design consideration.