PROPERTIES OF CONCRETE USING RICE STRAW ASH AS A PART OF CEMENT

Abstract

Workability, increasing cement replacement by rice straw ash about 15% by weight, was accompanied with difficulty in mixing the mortar by hand, as the water cement ratio maintained constant and no admixture were used to improve the workability. -Consistency, the experimental results on concrete showed an increase in the water needed in the standard consistency test as the ratio of RSA replacement increased. -Weight per unit volume of concrete is decreased as the content of RSA increased. The rate of increasing the unit weight at 28 days was height in the control mixes with Zero content of RSA compared to other mixes with RSA replacement. -Strength, in all mixes, the compressive strength with the passage

times. However, the 90 days compressive strength increased by

10% at the optimum RSA replacement at I 0% for mixes with ordinary Portland cement. -Rate of strength, the rate of strength development at the early ages of RSA concrete mixes slower than that of the control m1x. However, at later ages, the rate of strength development for RSA concrete mixes was higher than that of the control mixes. This is attributed to the delayed pozzolanic activity of the RSA.