No Fine Concrete

Abstract

No-fine concrete has been in use in many countries over more than a century. Its higher porosity helps in percolating rain water directly to ground and thereby helps in recharging groundwater aquifer. In this study, 3 batches of no-fine concrete each with two different sizes of aggregate were prepared to find the mix that generated high compressive strength and study the effect of percentage of fine aggregate on the compressive strength of no-fine concrete. The purpose of this project is to analyze the feasibility of producing highly sustainable no-fine concrete mixtures and evaluating the effect of fine aggregate on their properties. No-fine concrete is produced by using ordinary Portland cement, coarse aggregates, and water. This concrete is tested for its properties, such as slump value, porosity and compressive strength. The results showed that porosity has significant effect on compressive strength of no-fine concrete.
The study found that of the different admixtures tested, polypropylene fibers had the largest impact in improving durability. Including polypropylene 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 compressive 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 and twenty eight 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 minimum.