Effect of Foam Concentration on Structural Characteristics of Steel Reinforced Aerated Concrete Beams

ABSTRACT

This work presents the results of investigation conducted to evaluate the effect of foam concentration on the structural properties of steel- reinforced foamed aerated concrete beams. The properties investigated were the density, compressive strength, shear strength, and flexural strength. Relationships between compressive strengths and densities were developed, as well as comparison between the compressive strengths and the shear strengths. The foam concentrate/water ratios adopted in this investigation are 1:20, 1:25, 1:29, 1:33, 1:40, and 1:50. For the compressive strength and the dry density determinations, 150 x 150 x 150 mm cube specimens were cast and tested; and 225 x 225 x 2300 mm reinforced beam specimens were used for the shear and flexural strengths tests.

The results of the investigation shows that: (i) a reduction in foam concentration through the use of higher foaming agent to water ratio resulted in decrease in density, decrease in compressive strength and increased in deflection. (ii) there was increase compressive strength, density with curing ages at all foamed concentrations (iii) the relationship between the compressive strength and the density of the specimens were observed to be linear for all the foam concentrations, (iv) the mathematical expressions developed between the compressive strengths and the densities for the different foam concentration can be considered valid for the specimens used in this work, and (v) the shear strengths developed by the beam specimens used in this investigation were between 13.15% and 20% of the compressive strengths.

(Keywords: compressive strength, foamed aerated concrete, foam concentration, density, shear strength)