Pervious Concrete Pavements

رویه های بتنی

Pervious concrete pavement is a unique and effective means to meet growing environmental demands. By capturing rainwater and allowing it to seep into the ground, pervious concrete is instrumental in recharging groundwater, reducing stormwater runoff, and meeting U.S. Environmental Protection Agency (EPA) stormwater regulations. In fact, the use of pervious concrete is among the Best Management Practices (BMP) recommended by the EPA— and by other agencies and geotechnical engineers across the country—for the management of stormwater runoff on aregional and local basis. This pavement technology creates more efficient land use by eliminating the need for retention ponds, swales, and other stormwater management devices. In doing so, pervious  concrete  has the ability to lower overal project costs on a first-cost basis. In pervious concrete, carefully controlled amounts of water and cementitious materials are used to create a paste that forms a thick coating around aggregate particles. A pervious concrete mixture contains little or no sand, creating a substantial void content. Using sufficient paste to coat and bind the aggregate particles together creates a system of highly permeable, interconnected voids that drains quickly. Typically, between 15% and 25% voids are achieved in the hardened concrete, and flow rates for water through pervious concrete typically are around 480 in./hr (0.34 cm/s, which is 5 gal/ft2/ min or 200 L /m2/min), although they can be much higher. Both the low mortar content and high porosity also reduce strength compared to conventional concrete mixtures, but sufficient strength for many applications is readily achieved. While pervious concrete can be used for a surprising number of applications, its primary use is in pavement. This report will focus on the pavement applications of the material, which also has been referred to as porous concrete, permeable concrete, no-fines concrete, gap-graded concrete, and enhanced-porosity concrete. Although not a new technology (it was first used in 1852 (Ghafoori and Dutta 1995b), pervious concrete is receiving renewed interest, partly because of federal clean water legislation. The high flow rate of water through a pervious concrete pavement allows rainfall to be captured and to percolate into the ground, reducing stormwater runoff, recharging groundwater, supporting sustainable construction, providing a solution for construction that is sensitive to environmental concerns, and helping owners comply with EPA stormwater regulations. This unique ability of pervious concrete offers advantages to the environment, public agencies, and building owners by controlling rainwater on-site and addressing stormwater runoff issues. This can be of particular interest in urban areas or where land is very expensive. Depending on local regulations and environment, a pervious concrete pavement and its subbase may provide enough water storage capacity to eliminate the need for retention ponds, swales, and other precipitation runoff containment strategies. provides for more efficient land use and is one factor that has led to a renewed interest in pervious concrete. Other applications that take advantage of the high flow rate through pervious concrete include drainage media for hydraulic structures, parking lots, tennis courts, greenhouses, and pervious base layers under heavyduty pavements. Its high porosity also gives it other useful characteristics: it is thermally insulating (for example, in walls of buildings) and has good acoustical properties (for sound barrier walls). Although pavements are the dominant application for pervious concrete in the U.S., it also has been used as a structural material for many years in Europe (Malhotra 1976). Applications include walls for two-story houses, load-bearing walls for high-rise buildings (up to 10 stories), infill panels for high-rise buildings, sea groins, roads, and parking lots. Table 1 lists examples of applications for which pervious concrete has been used successfully, and Figure 2 shows several examples. All of these applications take advantage of the benefits of pervious concrete’s characteristics. However, to achieve these results, mix design and construction details must be planned and executed with care.

رویه های بتنی

رویه های بتنی

برای دانلود این کتاب بر روی دانلود کلیک کنید

دانلود

مقالات ویژه:

Solid Mechanics and Its Applications_مکانیک جامدات و کاربردهای آن SUPER-HIGH-STRENGTH HIGH PERFORMANCE CONCRETE_ بتن با عملکرد فوق العاده بالا Seismic Design of Concrete Buildings to Eurocode 8_طراحی لرزه ای ازساختمان های بتنی یورو 8 Handbook on Concrete Block Paving – کتاب کفپوش های بتنی Concrete Fracture_ شکستگی بتن Concrete Recycling_ بتن بازیافتی Durability Design of Concrete Structures in Severe Environments_ طراحی دوام سازه های بتنی در محیط های سخت Experiment and Calculation of Reinforced Concrete at Elevated Temperatures_آزمایش و محاسبه تقویت شده بتن در دماهای مرتفع Best Practices Guide for High-Volume_راهنمای بهترین روش ها برای حجم بالا CEMENT and CONCRETE MINERAL ADMIXTURES_ مواد افزودنی معدنی برای سیمان و بتن CONCRETE FOR UNDERGROUND STRUCTURES_بتن سازه های زیرزمینی  Concrete Buildings in Seismic Regions_ کتاب ساختمان های بتنی در نواحی زلزله خیز