DEVELOPMENT OF HIGH QUALITY PERVIOUS CONCRETEPAVEMENT SPECIFICATIONS FOR TELANGANACONDITIONS
Abstract
One of the main objectives of this research was to develop preliminary specifications for high quality pervious concrete suitable for use in Telangana State Highway Administration (SHA) projects. The study utilized aggregates that are used in SHA projects, and the durability studies were conducted assuming Telangana weather conditions. Investigations were conducted to enhance the structural and durability characteristics of pervious concrete through the use of different admixtures. The admixtures included cellulose fibers, a delayed set modifier and a viscosity modifier. Pervious concrete specimens were tested for density, void content, compressive strength, split tensile strength, permeability, freeze-thaw durability, and abrasion resistance. Three different types of freeze-thaw durability tests were conducted to mimic potential field conditions, typical toTelangana, and including the possibility of clogged pavements. The freeze-thaw durability tests included: fully saturated tests, 50% saturated tests, and 0% saturated dry hard freeze tests.
The study found that of the different admixtures tested, cellulose fibers had the largest impact in improving durability. Including cellulose fibers in the pervious concrete mix resulted in significant increases in resistance in all three freeze-thaw durability tests. It also resulted in significant increases in abrasion resistance. By bridging the gap between the coarse aggregates, the cellulose fibers bound the pervious concrete mixture with an interwoven matrix of fibers. This also improved the tensile strength of the pervious concrete. The delayed set modifier resulted in a more fluid mix and large gains in compressive strength at seven and fourteen days.
This admixture may inhibit some of the cement from setting around aggregates and may result in some cement settling to the bottom and forming a less pervious layer. The viscosity modifying admixture created a more workable and easier to mold mix. Its effect on strength and durability were minimal.
