A Study Of Pumping Ability On Crumb Rubber Concrete

Crumb Rubber Concrete (CRC) is a new kind of environmental-protection building material with crumb rubber as a constituent from discarded tires, which is also called Rubberized Concrete. Based on a series of material experiments and some existing literature results, this paper makes the first step on the possibility research of the pumping ability of Crumb Rubber Concrete.The paper presents a study on the relationship between slump and the sand percentage in crumb rubber concrete (CRC). Here, the sand percentage is defined as the ratio of fine aggregate (sand) to coarse aggregate. The amount of added crumb rubbers takes the volume by 0%, 5%, 10% and 15%. Taking the equivalency in volume between crumb rubber and fine aggregate in establishing the formula for determining sand percentage is proposed. The results show that the optimum sand percentage is decreased along with the increase of added crumb rubbers.In this study, a modifies apparatus is developed to measure the adhesion coefficient of the fresh concrete with different amount of added crumb rubbers, which can takes a volume up to 100kg/m~3. It is discovered that several factors (W/C, sand percentage, fly ash and water reducers) play a major role in affecting the adhesion coefficient of CRC, and a desirable rheological properties of fresh concrete may be achieved by adjusting those factors.The results also show that CRC strength reduces as the rubber is contended in concrete. With the rubber content of 150kg/m~3, the CRC compressive strength under 28 days decreases by as much as 51.2%.