Showing papers on "Pervious concrete published in 2007"

Evaluation of Four Permeable Pavement Sites in Eastern North Carolina for Runoff Reduction and Water Quality Impacts

Abstract: Four permeable pavement applications in North Carolina’s Coastal Plain were constructed and monitored to determine their effectiveness of reducing runoff quantity and improving water quality. Sites were either constructed of permeable interlocking concrete pavers (2), porous concrete (1), or concrete grid pavers (1). One site of each pavement type was monitored for runoff reduction for periods ranging from 10 to 26 months. Measured runoff depths from rainfall events over 50 mm were used to determine permeable pavement equivalent curve numbers for the sites, which ranged from 45 to 85. Only the two permeable interlocking concrete pavement (PICP) sites were monitored for water quality. Runoff and exfiltrate samples were intended to be collected, in addition to runoff monitoring, from the Swansboro PICP site. However, no runoff was produced during this study from the Swansboro PICP site for rainfall events up to 88 mm . From exfiltrate concentrations, nutrient retention was estimated to be 3.4 and 0.4 kg∕ha∕...

Aggregate Effects on Pervious Portland Cement Concrete Static Modulus of Elasticity

Abstract: The effects of aggregate gradation, amount, and size on pervious portland cement concrete (PCC) static modulus of elasticity were compared using four different mixtures. A standard mix and three variable mixes using a uniform gradation, increased aggregate amount, and increased aggregate size were used. The effective air void content was determined for each mixture. The compressive strengths and static elastic moduli were determined and compared at equal void contents. For a uniform gradation, the compressive strengths and static elastic moduli appeared to be higher within an optimal range of voids; however, there was no statistically significant difference between the results from the different gradations. An increased aggregate amount resulted in a statistically significant decrease in both compressive strength and static elastic moduli due to the subsequent decrease in paste amount. While the compressive strengths were higher for mixtures containing smaller aggregate sizes, there was no significant difference between the static elastic moduli when different aggregate sizes were used. Further research is needed to understand the effects of aggregate size on the static modulus of elasticity of pervious PCC.

Evaluation of an infiltration best management practice utilizing pervious concrete

Abstract: A pervious concrete infiltration basin was installed on the campus of Villanova University in August 2002. A study was undertaken to determine what contaminants, if any, were introduced to the soils underlying the site as a result of this best management practice (BMP). The average infiltration rate at the site is approximately 10 -4 cm/s. The drainage area (5,208 m 2 ) consists of grassy surfaces (36%), standard concrete/asphalt (30%), and roof surfaces (30%) that directly connect to the infiltration beds via downspouts and storm sewers. Composite samples of infiltrated stormwater were collected from the vadose zone using soil moisture suction devices. Discrete samples were collected from a port within an infiltration bed and a downspout from a roof surface. Samples from 17 storms were analyzed for pH, conductivity, and concentrations of suspended solids, dissolved solids, chloride, copper, and total nitrogen. Copper and chloride were the two constituents of concern at this site. Copper was introduced to the system from the roof, while chloride was introduced from deicing practices. Copper was not found in porewater beneath 0.3 m and the chloride was not significant enough to impact the ground water. This research indicates that with proper siting, an infiltration BMP will not adversely impact the ground water.

Properties of Concrete Containing Nonground Ash and Slag As Fine Aggregate

Abstract: The possibility of using granulated blast-furnace slag (GBFS), furnace bottom ash (FBA), and their combination as fine aggregates in concrete was studied by performing experiments These materials were used without applying any preprocesses such as sieving and grinding The compressive, flexural, and split tensile strengths of concretes with natural sand replaced with GBFS, FBA, and GBFS plus FBA at 10, 20, 30, 40, and 50% were examined at a fixed water-cement ratio (w/c) The percentages represent the replacement percentage of fine aggregate by GBFS, FBA, or their combination and were evaluated depending on weight basis Also, microstructure and water absorption capacity of concrete were researched Test results showed that concrete strength decreases with increasing replacement ratio with respect to reference concrete In addition, FBA decreases the strength of concrete more than GBFS In particular, the strength of concrete was detrimentally affected when the replacement ratio was beyond 40% The microstructure studies showed that different pore structures were formed in the concrete depending on the replacement material, that is, GBFS or FBA It is concluded that the main reason for the strength reduction in new concrete is the formation of a porous concrete structure Moreover, an increase trend in water absorption capacity was observed for both replacement materials

Temperature Effects on the Infiltration Rate through an Infiltration Basin BMP

Abstract: Infiltration Best Management Practices (BMPs) are becoming more readily acceptable as a means of reducing postdevelopment runoff volumes and peak flow rates to pre-construction levels, while simultaneously increasing recharge. However, the design, construction, and operation of infiltration basins to this point have not been standardized due to a lack of understanding of the infiltration processes that occur in these structures. Sizing infiltration BMPs to hold and store a predetermined volume of runoff, typically called the Water Quality Volume, has become a widely accepted practice. This method of sizing BMPs does not account for the infiltration that is occurring in the BMP during the storm event; which could result in significantly oversized BMPs. The objective of this study was to develop a methodology to simulate varying infiltration rates observed from a large scale rock infiltration basin BMP. The results should aid in improved design of such structures. This methodology is required to predict the performance of these sites using single event and continuous flow models. The study site is a Pervious Concrete Infiltration Basin BMP built in 2002 in a common area at Villanova University. The system consists of three infiltration beds filled with coarse aggregate, lined with geotextile filter fabric, overlain with pervious concrete and underlain by undisturbed silty sand. The BMP is extensively instrumented to facilitate water quantity and quality research. The infiltration performance of the site is the focus of the study. Recorded data indicates a wide variation of linear infiltration rates for smaller storm events. A model was developed using the Green — Ampt formula to characterize the infiltration occurring in the basin for small storm events characterized by an accumulated depth of water in the infiltration bed of less than 10 cm. The effectiveness and accuracy of the model were measured by comparing the model outputs with observed bed water elevation data recorded from instrumentation on site. Results show that for bed depths of <10 cm, hydraulic conductivity is the most sensitive parameter, and that the storm event measured infiltration rate is substantially less then the measured saturated hydraulic conductivity of the soil. The governing factor affecting hydraulic conductivity, and subsequently, infiltration rate is temperature; with higher rates occurring during warmer periods, affecting the infiltration rate by as much as 56%.

Portland cement pervious concrete pavement: field performance investigation on parking lot and roadway pavements

Abstract: Portland cement pervious concrete (PCPC) has an excellent performance history in the Southeastern United States, but until recently has seen limited use in environments with significant freeze-thaw cycles. Therefore, assessment of actual field performance is important. This project documents field observations, and nondestructive testing results of PCPC sites located in the states of Ohio, Kentucky, Indiana, Colorado, and Pennsylvania. PCPC is most often used as a pavement for parking lots. Field performance depends on the quality of the mixture as well as proper control of construction and curing. In addition to field observations and nondestructive testing, laboratory testing was performed on cores removed from some of the test sites. Generally, the PCPC installations evaluated have performed well in freeze-thaw environments with little maintenance required. The research goals included developing recommendations as to how to build PCPC pavements in freeze-thaw environments, and how to prevent clogging. Observations suggest that providing sufficient drainage under PCPC pavements to keep them from becoming saturated in freezing weather is likely to be effective. Site specific observations of clogging patterns provided insight into sources of clogging, and how these may be avoided.

Hydrologic Design of Pervious Concrete

Abstract: A properly designed pervious concrete pavement system can reduce the environmental impact often associated with development. Pervious concrete pavement systems can also be used to improve the environmental performance of existing sites without compromising the business value of a property by replacing existing conventional pavements. The capability to simultaneously maintain water quality, reduce flooding, increase base flow, and preserve valuable parking areas for the property owner, especially in retrofit applications, are capabilities not easily obtained with other water quality or flood mitigation alternatives. Pervious concrete also provides a unique leadership opportunity for stewardship in context-sensitive construction and Low-Impact Development (LID). This document describes the fundamental hydrologic behavior of pervious concrete pavement systems and demonstrates basic design methodologies appropriate for a variety of sites and circumstances. This document also briefly discusses limitations of these methodologies.

Pervious Concrete for Sustainable Development

Abstract: Pervious concrete is a special type of concrete with a high porosity used for concrete flatwork applications that allows water from precipitation and other sources to pass through it, thereby reducing the runoff from a site and recharging ground water levels. The void content can range from 18 to 35% with compressive strengths of 400 to 4000 psi. The infiltration rate of pervious concrete will fall into the range of 2 to 18 gallons per minute per square foot (80 to 720 liters per minute per square meter). Typically pervious concrete has little to no fine aggregate and has just enough cementitious paste to coat the coarse aggregate particles while preserving the interconnectivity of the voids. Pervious concrete is traditionally used in parking areas, areas with light traffic, pedestrian walkways, and greenhouses. Pervious Concrete is an important application for sustainable construction.

Hydraulic Performance Assessment of Pervious Concrete Pavements for Stormwater Management Credit

Abstract: Portland cement pervious concrete’s ability to infiltrate water has encouraged its use for stormwater management However, the material has suffered historically poor acceptance due to a lack of data related to long term infiltration rates and rainfall retention which leads to an undefined credit for stormwater management Before stormwater management credit could be estimated, it was necessary to develop a testing device to gather information from existing pervious concrete parking lots currently in use Eight parking lots were examined to determine the infiltration rates of the pervious concrete, as well as to assess the soil makeup beneath pavement A total of 30 pavement cores were extracted and evaluated for infiltration rates Three of the sites had a pervious concrete section that included a gravel reservoir Infiltration rates were measured using the application of an embedded single-ring infiltrometer A mass balance model to simulate the hydrologic and hydraulic function of pervious concrete sections was developed The purpose of the model is to predict runoff and recharge volumes for different rainfall conditions and hydraulic properties of the concrete and the soil The field derived hydraulic data were used to simulate infiltration volumes and rainfall excess given a year of rainfall as used in a mass balance operated within a spreadsheet The results can be used for assessing stormwater management credit

Performance Assessment of Portland Cement Pervious Pavement

Abstract: A pervious concrete shoulder was constructed along a rest stop on Interstate 4 in central Florida. The shoulder was 90 feet long and 10 feet wide. The depth of pervious concrete was 10 inches. A 12 inch deep reservoir consisting of select pollution control materials was used beneath the pervious concrete. The shoulder was monitored over a one year period for wear and stormwater management. The shoulder was monitored for traffic counts recording approximately 500 axles per week. This use included stopping and starting and sometimes the stops were rapid as the truckers did prefer to park on the hard surface pervious concrete area. There was no visual wear noted on the concrete. An embedded single ring infiltrometer was used to monitor the infiltration rates. The rate of infiltration did not decrease with time. The average rates of infiltration over one year were 2.5 inches per hour at a head of zero to one inch; 4.8 inches per hour at a six inch head; and 6.3 inches per hour at a nine inch head. An acceptable rate of infiltration for these designs is 1.5 inches per hour. Water quality leaving the reservoir was about equal to rainwater quality. The amount of water from the collection pipe nearest the edge of pavement was about 50 times the volume from the collection pipe seven feet from the edge of pavement. The demonstration using pervious concrete was considered a success based on wear, water quantity, and water quality considerations. It is recommended for other similar locations.

Pervious concrete pavement system capable of collecting rainwater

Abstract: The present invention relates to a rainwater-collecting permeable concrete pavement system. It is characterized by that said pavement structure includes rammed earth layer whose thickness is greater than 10mm, general concrete base layer whose thickness is 80-100 mm, permeable concrete structure layer whose thickness is 100-150 mm and permeable concrete face layer whose thickness is 40-60mm from bottom to top. Said pavement system is adjacent to green belt, under the green belt a rainwater-collecting pool is set, and the bottom portion of said rainwater-collecting pool is equipped with a submersible pump. Along the length direction of said pavement structure two sides of said pavement system are respectively equipped with a rainwater-collecting channel, the outlet of said submersible pump is connected with pipe network, and said pipe network is distributed in the green belt.

Construction and Maintenance Assessment of Pervious Concrete Pavements

Abstract: The information in this report focused on the construction and maintenance activities for Portland cement pervious concrete as used in selected sites in Florida, Georgia, and South Carolina. Construction specifications were suggested for Portland cement pervious concrete pavement in regional conditions typical to the States of Florida, Georgia, and South Carolina based on current construction practices and updated as a result of this research. Contractor certification is necessary. A total of 30 pervious concrete cores were extracted from actual operating pervious concrete sites and evaluated for infiltration rates before and after various rehabilitation techniques. The pervious concrete field sites investigated ranged in service life from 6 to 20 years and exhibited regionally similar structural integrity, infiltration rates, pavement cross sections and subsurface soils. The infiltration rates were performed at the same pressure head for comparative purposes. The techniques were pressure washing, vacuum sweeping and a combination of the two methods. For cores from pavements properly installed, it was found that the three methods of maintenance typically resulted in a 200% or greater increase over the original infiltration rates of the pervious concrete cores. However, it was noted that pressure washing may dislodge pollutants that can not be captured before entering receiving waters, thus in these situations, vacuum sweeping may be the preferred method.

Feasibility study of water purification using vertical porous concrete filter

Abstract: Cheapest and simplest techniques of filtration systems are required for rural water treatment in developing countries. Using a filter made of blocks for the water treatment enables us to make porous concrete filter and use it vertically. It is expected that the required area would decrease by more than 70 % if porous concrete filters were used vertically. The operation and backwash mode would be simpler than using horizontal sand filters as filters made of blocks would be used instead. The feasibility study focused on finding adequate materials, compositions and methods of making a block with enough resistance to water pressure, sufficient porosity for water transformation and using inexpensive and available materials. A pilot study was performed to determine an appropriate thickness of filter. Testing the porous filter in another pilot study using the low overflow rate of river water showed biological growth in that media and an adequate efficiency of about 90–100 % was obtained for decreasing the coliform bacteria. The required backwash water was 2.9 % of total treated water.

Effectively Estimating In situ Porosity of Pervious Concrete from Cores

Abstract: Pervious concrete is an alternative pavement material which may help reduce nonpoint source pollution problems. The porosity of pervious concrete is an important parameter used for both pavement and environmental design and is dependent on field placement techniques. It is recommended that porosity be tested on field-placed specimens. It has been noted that some of the concrete is knocked out while coring from field-placed samples which may affect the porosity. This paper researches a methodology for estimating the in situ porosity of pervious concrete from the porosities of cores taken from the field based on aggregate size, core size and porosity.

Method for detecting surface porosity on road surface of pervious concrete, and porosity on section of test block

Abstract: A method for detecting porosity of pavement surface prepared by water penetration concrete includes brushing a layer of color juice on detection region of pavement surface, covering a white paper on brushed region before color juice is divided off, pressing balanced pressure on white paper fro mark-printing out print image being inputted into computer to carry out pixel binary treatment for calculating out area ratio of color print on complete white paper and utilizing a formula to calculate out porosity of concrete pavement surface based on said area ratio.

Performance assessment of Portland cement pervious pavement: report 1 of 4: hydraulic performance assessment of pervious concrete pavements for stormwater management credit

Abstract: This report is part two of a four part report that explores the performance of pervious concrete at sites where it has been in use for several years. The reports 1. examine infiltration rates for eight pervious concrete parking lots and their subsoils; 2. investigate pervious concrete construction and maintenance techniques; 3. review the compressive strength of pervious concrete compared to conventional concrete; and 4. evaluate the wear and infiltration of a pervious concrete roadway shoulder.

Color pavement formed by spraying on porous polymer concrete facing and construction method therefor

Abstract: A colorful road plated with porous polymer concrete face and relative construction first mix polymer, broken stone and stuff uniformly to form polymer porous concrete material, lay to form polymer porous concrete face 1, mix uniformly the colorful face, and plate colorful face on the face of porous polymer concrete face layer 1 to form a colorful face layer 2, while the colorful face layer 2 is adhered with the porous polymer concrete face layer 1, to form a colorful road. The inventive road has high strength, better deformation property, abrasion resistance or the like, while the color can adjust via different fields.

Manufacturing methods of high performance concrete for kelp forest regeneration utilizing industrial by-products and kelp forest regeneration concrete block by using it

Abstract: A method of manufacturing high performance concrete for kelp forest regeneration and a kelp forest regeneration concrete block consisting of the concrete are provided to obtain numerous continual gaps and large specific surface area for marine life, and to restore marine ecosystem ultimately in short time. A method of manufacturing high performance concrete for kelp forest regeneration comprises a step of laminating a leachy porous concrete layer for restoring marine ecosystem and a conventional concrete layer for structural stability. The leachy porous concrete comprises mixed cement for marine concrete selected from blastfurnace slag cement having 2.9-3.2g/cm^3 of density and 3,000-4,300cm^2/g of particle size degree which comprises 5-60% by mass of pulverized powder of blastfurnace slag power and fly ash cement having 2.5-3.3g/cm^3 of density and at least 2,500cm^2/g of particle size degree which comprises 5-30% by mass of pulverized powder of fly ash; coarse aggregate selected from one mixture comprising 0.5-100Vo.% of crushed stone having 5-30mm of particle size range, 2.45-2.92g/cm^3 of density, 1,500-1,800kg/m^3 of bulk density, 0.3-2.9% of absorption rate and 52.0-66.0% of ratio of absolute volume or cinder coarse aggregate having 2.25-2.70g/cm^3 of density, 1,220-1,650kg/m^3 of bulk density, 1.0-4.0% of absorption rate and 48.0-62.0% of ratio of absolute volume with respect to the volume of the crushed stone having the same particle size degree for incorporation or usage; filler comprising 0.5-40% by mass of cinder powder having 5mum-2.5mm of particle size range, 2.0-2.6g/cm^3 of density, 1,150-1,380kg/m^3 of bulk density, 0.5-4.5% of absorption rate and 45.0-58.0% of ratio of absolute volume with respect to the cement for incorporation; reaction booster for cinder powder comprising 0.03-5.5% by mass of NaCl, Ca(OH)2 or NaOH in the form of powder with respect to the cement for incorporation; and admixing agent comprising 0.2-2.0% by mass of high performance superplasticizer or high range water reducing admixture with respect to the cement for addition while the ratio for water-cement is 15-45% for obtaining 8-40% of total porosity with respect to total concrete volume. The kelp forest regeneration concrete is constructed with the high performance cement having double layer structure consisting of the leachy porous concrete layer and the conventional concrete layer.

Desarrollo de mezclas de hormigón poroso para pavimentos urbanos permeables

Abstract: The present study aimed to analyze the hydraulic and mechanical behaviour of a series of roller-compacted, laboratory porous concrete mixtures. The mix design variables examined were the actual void ratio in the hardened concrete and the water/cement ratio. From these results the better dosages from the mechanical and hydraulical behaviour point of view were determined. One of the designs developed was found to exhibit excellent hydraulic capacity and 20% greater strength than the mixtures recommended in the literature. Moreover, concrete with an actual void ratio of only 14% was observed to meet permeability requirements. Maximum flexural strength of concretes with different w/c ratios was achieved with a cement paste content of 250 l/m3. Relationships were found between the void ratio and both 28-day concrete permeability and flexural strength. Finally, the doses exhibiting the best mechanical and hydraulic performance were identified.

The Influence of Some Surfactants on Porous Concrete Properties

Abstract: Expanded polystyrene is used as packing material in various industrial fields in the world. A large quantity of expanded polystyrene is consumed, and is disposed as a waste. On purpose to utilize packing tare waste of expanded polystyrene, composite material is created. The matrix in this composite material is porous concrete and insertion – crushed tare waste. The properties of composite matrix are analyzed comprehensively in this article. As it is known, porous concrete is one of types of lightweight concrete. One of ways to get porous concrete is the usage of surfactants in the formative mixtures. It has been widely used to decrease the density of concrete and to improve its thermal properties. The surfactant molecules help entrain air bubbles and stabilize them in the fresh cement paste. Researches with 6 different types of surfactants were made. The Ufapore TCO surfactant was chosen for the further research as the most suitable for production of composite material.

Performance Assessment of a Pervious Concrete Pavement Used as a Shoulder for an Interstate Rest Area Parking Lot

Abstract: A pervious concrete shoulder was constructed along a rest stop on Interstate 4 in Central Florida. The shoulder was 90 feet long and 10 feet wide. The depth of pervious concrete was 10 inches. A 12 inch deep reservoir consisting of select pollution control materials was used beneath the pervious concrete. The shoulder was monitored over a one year period for wear and stormwater management. The shoulder was monitored for traffic counts recording approximately 500 axles per week. This use included stopping and starting and sometimes stops were rapid as the truckers did prefer to park on the hard surface pervious concrete area. There was no visual wear noted on the concrete. An embedded single ring infiltrometer was used to monitor the infiltration rates and the rate of infiltration did not decrease with time. Water quality leaving the reservoir was about equal to rainwater quality and the amount of water from the collection pipe nearest the edge of the pavement was about 50 times the volume from the collection pipe seven feet from the edge of the pavement. The demonstration using the pervious concrete was considered a success based on wear, water quantity, and water quality considerations and it is the shoulder is recommended for other similar locations.

Performance assessment of a pervious concrete pavement used as a shoulder for a interstate rest area parking lot: report 4 of 4: hydraulic performance assessment of pervious concrete pavements for stormwater management credit

Abstract: This report is part one of a four part report that explores the performance of pervious concrete at sites where it has been in use for several years. The reports 1. examine infiltration rates for eight pervious concrete parking lots and their subsoils; 2. investigate pervious concrete construction and maintenance techniques; 3. review the compressive strength of pervious concrete compared to conventional concrete; and 4. evaluate the wear and infiltration of a pervious concrete roadway shoulder.

Performance Assessment of Portland Cement Pervious Pavement Report 2 of 4: Construction and Maintenance Assessment of Pervious Concrete Pavements

Abstract: The information in this report focused on the construction and maintenance activities for Portland cement pervious concrete as used in selected sites in Florida, Georgia, and South Carolina. Construction specifications were suggested for Portland cement pervious concrete pavement in regional conditions typical to the States of Florida, Georgia, and South Carolina based on current construction practices and updated as a result of this research. Contractor certification is necessary. A total of 30 pervious concrete cores were extracted from actual operating pervious concrete sites and evaluated for infiltration rates before and after various rehabilitation techniques. The pervious concrete field sites investigated ranged in service life from 6 to 20 years and exhibited regionally similar structural integrity, infiltration rates, pavement cross sections and subsurface soils. The infiltration rates were performed at the same pressure head for comparative purposes. The techniques were pressure washing, vacuum sweeping and a combination of the two methods. For cores from pavements properly installed, it was found that the three methods of maintenance typically resulted in a 200% or greater increase over the original infiltration rates of the pervious concrete cores. However, it was noted that pressure washing may dislodge pollutants that can not be captured before entering receiving waters, thus in these situations, vacuum sweeping may be the preferred method.

Permeable concrete using slag as aggregate

Abstract: This invention relates to a pervious concrete technology, which utilizes slag as the aggregate of pervious concrete in the following ratio: cement 300-500kg/S, slag 1700-2100kg/S, grounting agent 0.03-0.045 times of the mass of the cement and water 0.3-0.35 times of the cement mass, which applies slag in stead of carpolites to increase the road-use performance of the pervious materials doped with slag and increase the safety factor of road surfaces to improve the water circulation function of the environment.

Construction and maintenance assessment of pervious concrete pavements: report 2 of 4: hydraulic performance assessment of pervious concrete pavements for stormwater management credit

Abstract: This report is part two of a four part report that explores the performance of pervious concrete at sites where it has been in use for several years. The reports 1. examine infiltration rates for eight pervious concrete parking lots and their subsoils; 2. investigate pervious concrete construction and maintenance techniques; 3. review the compressive strength of pervious concrete compared to conventional concrete; and 4. evaluate the wear and infiltration of a pervious concrete roadway shoulder.

Evaluation of Various Types of Permeable Pavements with Respect to Water Quality Improvement and Flood Control

Abstract: In North Carolina and several other U.S. states, all permeable pavements are currently considered to have similar capabilities in reducing runoff, but are not credited with improving water quality. Previous research conducted by the North Carolina State University on one particular permeable block pavement type has shown that when compared to runoff from an adjoining asphalt lot, permeable pavement exfiltrate contained significantly lower concentrations of phosphorous and zinc, as well as reductions in total nitrogen. To further test various permeable pavement designs, a parking lot consisting of four different types of permeable pavements and standard asphalt was constructed in Kinston, NC. The permeable pavement sections consist of permeable interlocking concrete pavers (PICP) with 8.5 % void space, PICP with 12.9 % void space, concrete grid pavers (CGP), and porous concrete (PC), each covering a 1200 sq. ft. area with a 10 in. gravel storage layer. The purpose of this study is to evaluate and compare the effects of each pavement type on water quality and runoff reduction. Conclusions on the difference in reduction between each pavement type have not been determined. Site analyses on every rainfall event will be conducted beginning January, 2006 and will continue for one year. As a result of the Kinston study, it is expected that the state of North Carolina will be able to make an informed judgment on how much pollutant removal credit permeable pavements should receive when implemented as stormwater best management practices. Also, this study can be used to determine whether or not stormwater credit should vary based on pavement type.

Method of modifying porous vegetation concrete pore alkalinity

Abstract: This invention relates to a reform method for alkalinity of holes for porous vegetation concrete, which confects spraying solution, carries out filming by spraying and film solidification to form a densed macromolecular film layer on the surfaces of the holes, so that the filled soil in the holes is not basified and keeps neutral for a long time, which is suitable for the growing of vegetable roots and does not influence the strength of porous concrete.

No-fines concrete as ecologic stream bank erosion control

Abstract: No-fines concrete is a pervious concrete obtained by eliminating the sand from normal concrete mix. Compared with conventional concrete, no-fines concrete has unique properties desirable for various applications. Because of the presence of large voids, no-fines concrete has lower density, cost and thermal conductivity, smaller dying shrinkage, no segregation, larger contaminant retaining capability, and reduced capillary movement of water. No-fines concrete is used for construction of pavement, storm water control utilities and green houses. This paper discusses the application of no-fines concrete as an ecology preservative method for stream bank erosion control. Soil erosion is an important factor that can trigger the instability of an embankment. A sustainable revetment should provide soil erosion protection without significantly changing the existing ecologic environment. The strength of no-fines concrete provides sufficient protection against scour of embankments. Although grasses are found to be hard to survive with ordinary types of bank revetment, especially when subjected to periodic inundation from river water level fluctuations, the large pore spaces of no-fines concrete protect grass seeds and provide an environment for grasses to grow. By installing artificial access holes in the no-fines concrete revetment, the ecologic conditions can be preserved to the maximal extent. The design criteria and durability of no-fines concrete revetments are discussed in this paper. This paper also provides an example application of a no-fines concrete revetment that achieved the desirable ecologic effects.

Porous concrete having fertilizer component

Abstract: PROBLEM TO BE SOLVED: To provide porous concrete having fertilizer components easily constructed and also excellent in fertilizer effect. SOLUTION: The porous concrete having fertilizer components is obtained by using material having fertilizer and fertilizer components as part of the porous concrete material, using wood-base biomass incinerated ash as the fertilizer components, and using dried crushed-stone peat as porous concrete aggregate. When the porous concrete is used for bank protection work, the conventional porous concrete using aggregate and binding material is applied as an upper layer and the porous concrete in the present invention is applied as a lower layer so as to make the bank protection have a double-layer structure. COPYRIGHT: (C)2008,JPO&INPIT