USE OF HOMRA POWDER IN SELF-COMPACTING CONCRETE

Although 5-10% of the production of clay bricks in Egypt is considered as wastes, their
use in concrete is still limited. This study investigates the use of hornra powder as a partial
replacement of cement and the influence of the total powder content on the properties of self￾compacting concrete (SCC). The cement content for concrete mixes ranged from 250 to 400
Kg/m3 and that of powdered homra from zero to 150 Kg/m3, in order to obtain a total powder
content of 400 Kg/m3. A Viscocrete admixture is introduced in these mixes with three
different contents: 1, 1.5 and 2% of the total powder content. In addition to the 400 Kg/m3
total powder content three other contents of 500, 550 and 600 Kg/m3 with 2% of the total
powder content superplasticizer are studied and compared with that of 400 Kg/m3. The self￾compactability of concrete is measured by means of slump flow, V-funnel, L-box and
resistance to segregation tests. Also the influence on the compressive strength is studied using
cubes poured without any internal or external compaction. The results showed that the
optimum dosage of Viscocrete admixture in SCC with a total powder content of 400 ~~lm~ is
2% of the total powder content, irrespective of the amount of cement. Addition of homra
powder as a partial replacement of cement resulted in a slight reduction in the concrete
flowability, noticeable decrease in compressive strength and prolonged initial and final setting
times of concrete. The use of high powder content (500-600 Kg/m3) with 2% superplacticizer
resulted in a concrete with high flowability and moderate viscosity that are necessary for the
successful casting of SCC.