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Pervious Concrete - When Rain Drains
- 1. PERVIOUS CONCRETE “when it rains… it drains…” NITHIN B 4VP11CV046 1
- 2. PERVIOUS CONCRETE • Pervious concrete sometimes referred to as “no-fines concrete,” is a mixture of hydraulic cement, coarse aggregate of smaller size, admixtures and water. • Pervious concrete allows the water to percolate through the concrete into the sub-base and recharge the underground water level. • Typically, pervious concrete does not contain any sand and its air void content varies between 15 and 30% 2
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- 6. ADVANTAGES 1.Environmental ▲ Reduces the size and sometimes the need for storm water runoffs ▲ Recharges the ground water level ▲ Allows for the natural treatment of polluted water by soil filtration ▲ Does not create heat islands due to its light color ▲ Reduces risk of flooding and top soil wash away ▲ Improves the quality of landscaping and reduces the need for watering 6
- 7. 2.Safety • Reduces tire noise • Prevents glare • Reduces hydroplaning and flooding 3.Economics • Reduces or eliminates the need for storm sewers or retention ponds • Increases facilities for parking by reducing water retention areas • Requires less costly repairs than black top • Longer service life and lower life cycle cost than asphalt 7
- 8. 8 DISADVANTAGES • Difficult in providing the reinforcements • Frequent maintenance is required • Compressive strength is comparatively less • Require more time and experimental works for the construction • It cant be used for the construction of bridges, buildings, dams and so on….
- 9. 9 MIX DESIGN Aggregates • Pervious concrete has little or no fine aggregates in the mixture. • Aggregate size is typically between 3/8 to1/2 inch maximum. • Natural or crushed aggregate can be used. In general, rounded aggregate will require less compaction effort than crushed aggregate. • The aggregate should be kept moist or wet especially when high temperatures are expected. • The aggregate to cement ratio usually falls between 4:1 to 5:1.
- 10. 10 Cementitious Materials • Typically Type I cement is used for the production of pervious concrete. • Supplementary cementitious materials such as flyash or slag can be used in exchange up to about 25% (flyash) and up to about 50% (slag) of cement. Water • Water meeting standard requirements for conventional concrete can be used for the production of pervious concrete. Admixtures • Water reducing admixtures may be used for lowering w/c ratio and increasing the strength of paste/mortar.
- 11. 11 Admixture Contin….. • Air Entraining Admixtures may be used to improve the freeze/thaw durability of the paste/mortar. • Retarding / Accelerating admixtures allow one to adjust the setting properties of concrete in relation to ambient conditions. • Color/pigment additives in powdered or liquid form can be used for the production of colored pervious concrete.
- 12. 12 Typical composition of Pervious Concrete
- 13. 13 CONCLUSIONS • The pervious concrete help the water to infiltrate , which is help full. • It is made by using without sand or fine aggregates. • The pervious concrete is mainly used for pavement constructions. • It cant be used for the construction of buildings because of its low strength.
- 14. 14 REFFERENCES • www.perviouspavement.org • A guide to pervious concrete
Notes de l'éditeur
- In spite of the realization that a promising avenue of economic activities has been opened up by Geosynthetics, the interdisciplinary nature of this industry and the current state of affairs of the Indian polymer and textile industries constitute serious hurdles of its growth. Lack of trained manpower is another concern. R&D issues would be primarily governed by the extent of cooperative activities of the interested parties, namely the designers, test organizations, suppliers, manufactures, and installers. There is a dire need to quickly break the barrier of isolation between the customer, consultant, contractor and the manufacturer. Unless necessary co-ordination is established, the true benefits of Geosynthetic materials shall not be realized. The most of the Geosynthetic material including woven and non-woven geotextiles are currently being imported / manufactured in India with technologies derived from various countries. As these are from different countries, it is obvious the test methodology varies from the country of origin. Therefore, there is a need for establishing a Geosynthetic institute in India. Formulation of Indian Standard relating to engineered Geotextiles / Geomembranes and allied products (natural and polymeric) for various civil engineering applications. There is a need to develop methods of tests, design construction and selection criteria. Even though BIS is publishing several documents the project related authorities are required to adhere more and more to the published national / international standards and guidelines. This will minimize the gap on required information for project clearance and completion. The end users and specifiers on Geosynthetic in the country must be aware of significant of technical parameters and their appropriate evaluation procedures. Development of a comprehensive manual is the requirement to achieve successfully implementation and long-term performance of the structures.