Evaluation of Mechanical Properties of Pervious Concrete with Changing Cement content

Abstract

Pervious concrete was first used in the nineteenth century but it has recently begun to increase in popularity. As urban areas expand, the problems associated with runof management have become more challenging. The focus on the negative en- vironmental effects associated with pavement runof has also increased. These two issues have increased the recent interest in pervious concrete pavements. Pervious concrete, however, has deficiencies which limit its application as pavements. These limitations include low compressive strength, exural strength, clogging, and other durability issues. In many developed countries, the use of pervious concrete for the construction of pavements, car parks and driveways is becoming popular. In order to develop ma- terial specification for pervious concrete, it is necessary to conduct tests to evaluate the performance of this new type of high-performance concrete. The pervious concrete is produced by using conventional cementitious materials, aggregates and water. This concrete is tested for its properties, such as density, porosity, compressive strength, water permeability and drying shrinkage. The most important property of pervious concrete is its water permeability. Earlier there were no standard procedure to determine the permeability. A method was therefore developed to determine the water permeability. To improve the acceptance of pervious concrete, it is necessary to improve the surface texture. Due to the rough surface texture and bigger void content, it may be difficult for pervious concrete for wide acceptance by the construction industry. The main objective of this investigation is to achieve a range of compressive strength & permeability by changing the cement content. Generally in pervious concrete sand is not used but to increase the compressive strength of pervious concrete, coarse aggregates will be replaced by various percentage of sand. The main properties to be studied are void ratio, compressive strength & permeability. For the measurement of permeability, a setup is developed known as Falling Head permeability test which is readily used all over the world. Pervious concrete is produced using two size of aggregates. The first is 4.75-10 mm i.e. size A (passing from 10 mm and retaining on 4.75 mm IS sieve) and second is 10-20 mm i.e. size B (passing from 20 mm and retaining on 10 mm IS sieve). For this experimental investigation, cement content is varied from 250 kg/m3 to 450 kg/m3 at an interval of 50 kg/m3. The aggregate/cement ratio is kept constant as 4. Three w/c are used i.e. 0.3, 0.35 and 0.4. Also, sand is used as a partial replacement of aggregates ranging from 0%-40% at an interval of 10%. In pervious concrete as the density increases compressive strength increases but subsequently the Permeability decreases. Throughout the experimental investiga- tion the density of pervious concrete ranged from 1860 kg/m3 to 2272 kg/m3. The 28 days compressive strength of pervious concrete ranges from 5.8 to 13.8 MPa for size A aggregates and 10.23 to 20.21 MPa for size B aggregates. The void content ranges from 11.78 to 25.72% for size A aggregates and 10.34 to 22.89% for size B aggregates. The permeability of pervious concrete ranges from 1.38 to 4.14 mm/s for size A aggregates and 1.03 to 2.07 mm/s for size B aggregates. The results shows the comparison between Compressive strength v/s Void ratio and Permeability v/s Void ratio. As the void ratio decreases the compressive strength increases and per- meability decreases and vice versa. Chapter 1 includes the introduction, objective and scope of work of the experimental investigation. Chapter 2 includes the literature review for the experimental inves- tigation. Chapter 3 includes the details of the experimental investigation. Chapter 4 includes the results and discussion of the experimental investigation. Chapter 5 includes the conclusions of the experimental investigation followed by references.