This paper experimentally measures the hydraulic conductivity of crumb-rubber modified masonry concrete using the falling head method. Six mix batches using a mix ratio of 1:1.5:3 and a water-cement ratio of 0.42 was used to produce masonry concrete having 0%, 5%, 10%, 15%, 20% and 25% crumb-rubber particles partially replaced by volume of coarse granite was used for the investigation. The results reveals that the reference masonry concrete (0%CR) have a hydraulic conductivity of 9.88 x 10-11 m/sec while the 5, 10, 15, 20 and 25% have hydraulic conductivity of 1.68 x 10-10 m/sec, 2.34 x 10-10 m/sec, 3.26 x 10-10 m/sec, 4.03 x 10-10 m/sec and 4.51 x 10-10 m/sec respectively; which indicates that the hydraulic conductivity of the modified masonry concrete increased with addition of more crumb-rubber content up to 25%. The outcome of these study implies an increase in the ability of the modified masonry concrete to absorb surface water which will be highly desirable for use as a pervious concrete to reduce storm water runoff.
Key words: Crumb-rubber, Masonry concrete, Unit weight, Compacting factor, Compressive strength and Hydraulic Conductivity.
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