Cellular Porous Brick—A Novel Permeable Pavement Strategy

Permeable pavement is generally considered as one of the most effective prac-tices of rainwater management. This paper analyses the defects of current permeable pavement. Inspired by the honeycomb bionic structure which has superior mechanical properties and structural efficiency, an innovative “honeycomb-like” model of permeable brick measuring 190 × 100 × 60 mm in size was proposed and constructed. The mechanical strength and permeability performance of the honeycomb permeable brick were experimentally assessed by universal testing machine and artificial rainfall equipment, respectively. Ex-periment results demonstrated an excellent performance in compressive toler-ance and permeability. The critical damage load (Fc) and compressive strength (Ec) of honeycomb brick were 336.46 KN and 17.70 MPa, which were 18.06% and 11.04% higher than that of ordinary solid permeable bricks, respectively, compared with the conventional permeable bricks. The honeycomb brick is capable of increasing the permeability coefficient by 19.2% and 11.96% under rainfall repetition period of 20 and 30 years respectively. These results demon-strated that the permeable brick with honeycomb-like structure can provide a new paving strategy for the construction of sponge city.

Utilisation of Geothermal Heat Pumps within Permeable Pavements for Sustainable Energy and Water Practices

Geothermal heat pumps （GHPs） are an attractive proposition for renewable energy worldwide as it uses energy naturally stored in the earth. The Earth is a very resourceful form of energy, using the natural solar energy collection and heat storage capabilities as an infinite heat source/heat sink at the base of permeable pavements, which can provide excellent temperature gradients for GHP＇s. Experimental rigs were setup up at The University of Edinbttrgh for a combined permeable pavement and GHP system. At the base of a pavement structure （approximately 1 meter） below the ground＇s surface, temperatures are constant of 10℃ in the U.K all year round. The GHP performance efficiency was analysed by the coefficient of performance （COP） in a heating cycle and the energy efficiency ratio （EER） in a cooling cycle. The mean COP and EER for both systems averaged between 2-4.5 and 3-5 respectively. The combined GHP and pavement structure operated at an optimum efficiency for both heating and cooling cycles and has shown to be unaffected by higher summer or lower winter temperatures. This hybrid system is an attractive renewable energy technology and has additional environmental benefits such as urban runoff reuse and recycling.

Paving Materials and Engineering Applications of Permeable Pavement

The stability of roads in cities directly affects the safety of traffic and transportation.In the process of pavement laying,relevant personnel should use permeable paving materials in the process of construction.Based on the analysis of road drainage requirements,traditional paving materials have relatively poor water permeability,which leads to ponding problems during road use[1].Within this frame of reference,beginning with the characteristics of permeable paving materials,this paper makes an in-depth exploration on practical application measures.

Pervious Concrete as an Alternative for Non-structural Drainage to the Amazon Region:From Properties to Applications in Watersheds

The urbanization process of the urban centers in the Amazon occurred quickly and without planning. Belém, one of the main cities in the region, suffers from intense flooding due to urbanization growth and the disorderly occupation of floodplains. The objective was to evaluate the producing of pervious concrete that meets the mechanical and hydraulic performance criteria for permeable pavement molded on site and to simulate the replacement of the entire public walkway system of a hydrographic basin in Belém in order to verify if this measure would alter the permeability of the basin and meet minimum requirements of at least 25% permeable area. The properties of three mixtures of pervious concrete with aggregates of different grading were evaluated. The permeability and flexural strength of all blends were higher than the minimum required for use as a permeable pavement for light vehicle traffic. The simulation showed that replacement of the public walkway by permeable pavement increased the permeable area of the watershed from 19 to 23%, changing from a poor condition to an acceptable level. The results indicate the potential to improve the performance of drainage systems through the wider use of permeable pavement associated with traditional structural measures.

RESIDENTIAL STORMWATER:METHODS FOR DECREASING RUNOFF AND INCREASING STORMWATER INFILTRATION

INTRODUCTION Humans and plants depend on an adequate supply of clean water for numerous reasons,from food production to sustaining terrestrial and aquatic life.The average Virginia resident uses about 47 gallons(178 L)of fresh water daily(VDEQ 2008).While a majority of Virginians are provided water from a centralized,public utility,there are nearly two million Virginia residents who depend on well water as their main source(VDH 2008).Replenishing groundwater withdrawals depends on recharge(water moving from the surface to groundwater)from infiltration of precipitation through permeable surfaces in the environment;an important part of the hydrologic,or water,cycle(VDEQ 2010).Forests and grasslands provide much of the available recharge area due to their high capacities to infiltrate precipitation.However,the urbanization process is rapidly converting forested areas and grasslands to commercial,residential,or industrial developments.This conversion creates a significant increase in impervious surfaces such as concrete,asphalt,building roofs,and even compacted vegetated sites(U.S.EPA 2003).Impervious surfaces decrease infiltration and groundwater recharge.They also generate increases in stormwater runoff;defined as any precipitation from a rain or snow event that flows off of an impervious surface.As water runs off urban impervious surfaces,it picks up sediment,oils,debris,nutrients,chemicals,and bacteria.The runoff is then collected in a conveyance system,transported,and discharged to surface waters such as creeks and rivers;most of the time without any type of water quality treatment(U.S.EPA 2003;Paul and Meyer 2001).In addition to carrying pollutants,the runoff is also typically warmer than the receiving surface waters.The increased volume and velocity of the stormwater runoff erodes soil and stream channels and can lead to stream“blow out.”Water quality is degraded and aquatic habitats are adversely altered(Meyer,et al.2005,Booth and Jackson 1997).Due to the interconnected nature of watersheds,the degraded water travels downstream causing subsequent problems.The effect of increased development is an increase in stormwater runoff and associated pollutants into surface waters and a decrease in infiltration for groundwater recharge and stream base flows.Traditional practices for mitigating stormwater runoff impacts have targeted the management of peak runoff by using storage facilities such as detention and retention ponds.Mounting evidence that these methods are inadequate prompted the National Research Council in 2008 to advocate a shift to Low Impact Development(LID)practices to better meet stormwater quality and quantity management goals.LID is based on a set of techniques used in Prince Georges County,Maryland(Prince Georges County 1999).LID seeks to restore the natural hydrology of a site by minimizing the creation of impervious surfaces and increasing infiltration of runoff volume.The ineffectiveness of conventional management approaches and the implementation of the Chesapeake Bay and other critical watershed Total Maximum Daily Loads(TMDLs)caused Virginia to revise its entire process for regulating stormwater.LID and Environmental Site Design(ESD)practices are now used to design sites to meet hydrologic goals and to treat runoff to meet a net site nutrient export standard(Battiata et al.2010).As of the date of this paper,15 of these best management practices,or BMPs,have been approved for use by Virginia(Virginia Stormwater BMP Clearinghouse 2011).Similar approaches are being considered and adopted in other Chesapeake Bay jurisdictions,as well as nationally.The responsibility of stormwater management can be fragmented between state,local,and municipal government(Roy,et al.2008),often differing from watershed to watershed.Because LID is decentralized,it changes the management focus from a large,regional scale to a site scale.Changes at the residential lot level can generate much greater infiltration over the watershed.Each homeowner can significantly reduce the stormwater load leaving their property,thereby improving surface water quality and helping to recharge groundwater reserves.From a green building perspective,LID techniques can provide a substantial credit under the LEEDS-ND(Leadership in Energy and Environmental Design-Neighborhood Development)program.The objective of this paper is to provide a relative context for runoff at the site scale,and an overview of the available BMPs that may be applicable.

DESIGNING FOR ENVIRONMENTAL AND INFRASTRUCTURE SUSTAINABILITY: ONTARIO CASE STUDIES FOR RETROFITS AND NEW DEVELOPMENTS

The Low Impact Development (LID) approach has been implemented worldwide for managing stormwater quantity and quality within the context of land development, re-development, and retrofits within an existing development site. Since the inception of the concept in the 1990s, the application of LID has covered different land uses, spatial scales, and environmental objectives, leading to an expanded vision for applying and testing the LID approach. Recently, holistic methodologies and frameworks have linked land planning to key ecological landscapes larger than the previous site scale practice. This new emerging paradigm considers the watershed, subwatershed, and neighbourhood, in addition to the site scale, and consequently, recommends a landscape-based LID and broader Green Infrastructure (GI) solutions (Benedict and McMahon, 2002;Tzoulas et al, 2007;NRDC, 2011). As part of the holistic understanding of land planning and environmental features and functions within the intended spatial scale, LID and GI measures have been designed and constructed as retrofit measures (i.e., measures implemented within existing development) and as measures implemented within new development areas. Under this new paradigm, the land planning context is linked to environmental objectives to provide end points for environmental conservation and restoration within an ecological landscape such as watersheds, subwatersheds, and stream corridors. This paper presents three case studies for the design and construction of LID and GI measures within different land use contexts and for providing multiple environmental objectives.