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Pervious concrete
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- 2. What is perviousconcrete ? Pervious concrete is a special type of concrete, which consists of cement, coarse aggregates, water and if required, admixtures and other cementitious materials. It is a concrete with high porosity used for concrete flatwork applications. It allows water from precipitation and other resources to pass through it. Used in parking areas with light traffic, residential streets, pedestrian walkways, and greenhouses
- 3. PERVIOUS CONCRETE PAVEMETS Controlled amounts of water and cementitious materials creates a paste that forms a thick coating around aggregate particles without flowing off during mixing and placing Has a 15-25% void structure, hence lightweight
- 5. Need of perviousconcrete A large amount of rain water ends up falling on impervious surfaces such as parking lots, drive ways, sidewalks, and streets rather than soaking into the soil. This creates an Imbalance to the natural ecosystem and leads to a host of problems including erosion, floods, ground water level depletion and pollution of rivers, lakes etc..
- 6. PERVIOUS VS IMPERVIOUSPAVEMENT Pervious concrete pavement Impervious concrete pavement
- 7. PROPERTIES 1. COMPRESSIVESTRENGTH : Falls in the range of 3.5 MPa to 28 Mpa . Typical values are about 17 Mpa 2. FLEXURAL STRENGTH : Ranges between about 1 and 3.8 Mpa Influenced by degree of compaction, porosity, and the aggregate-to-cement (A/C) ratio 3. DENSITY: Depends on The properties and proportions of the materials used Compaction procedures used in the placement In-place densities in the order of 1600 to 2000 kg/m3 –falls in upper range of lightweight concretes
- 8. 4. DURABILITY: FREEZE-THAW RESISTANCE It depend on the saturation level of the voids in the concrete at the time of freezing Voids are saturated, complete freezing can cause severe damage 5. ABRASION RESISTANCE Open and rough structure- abrasion and raveling of aggregate on the surface can be a problem Hence Highways are generally not suitable for pervious concretes
- 9. APPLICATIONS Residential roads, alleys and driveways • Low volume pavements. • Sidewalks and pavements. • Parking areas • Tennis courts • Swimming pool decks • Noise barriers
- 10. ADVANTAGES It rechargesground water directly. It Protects streams, watersheds, and ecosystems. It Reduces surface temperatures and heat island effects. It Eliminates need of expensive collection and detention systems. It Eliminates the cost of curb and gutter installations.
- 11. DISADVANTAGES Extended curingtime. It is more expensive to install as compared to traditional pavements. Limited use in heavy vehicle traffic areas. Frequent maintenance is required because it is prone to clogging. Compressive strength is low. It is not ideal for building , airport runways and highways.
- 12. WAYS OF IMPROVEMENTOF STRENGTH OF PERVIOUS CONCRETE Addition of small quantity of fine aggregates Addition of small quantities of cementitious materials. Usage of small sized coarse aggregates. Using low w/c ratio.
- 13. Recycling of disposalPolypropylene Blister Tablets and Strapping ties as fiber reinforcement for Pervious concrete
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- 19. CONCLUSION In thepast due to the scarcity of cement, the pervious concrete has been used extensively. The pervious concrete has lost its importance after successful production of cement in large quantities. But now-a-days, the usage pervious concrete has gained its popularity due to many advantages. The urban areas all over the world have become CONCRETE JUNGLES. The discharge of storm water is very difficult problem in the present conditions. By using the pervious concrete we can able to recharge the ground water table and the storm water disposal can also be done. So, in future it can tackle the aforesaid problems.