A comparative study of normal concrete with concrete which contained laterite instead of sand

Abstract

This paper reports the use of soft laterite as fine aggregate in structural concrete. The modulus of elasticity of $\text{1:1}\text{1}\text{2}\text{:3}$ by weight of concrete mix which contained soft laterite as fine aggregate was 1840 kg mm⁻² (2·62 × 10⁶ lbf in⁻²) as compared with the modulus of elasticity of normal concrete mix of $\text{1:2:4}$ of 2025 kg mm⁻² (2·88 × 10⁶ lbf in⁻²), whilst the compressive strength was 2·47 kg mm⁻² (3525 lbf in⁻²) against 2·82 kg mm⁻² (4000 lbf in⁻²) for normal $\text{1:2:4}$ mix.

The effect of exposure to high temperature of concrete which contained laterite is about the same as that for normal concrete for various mixes considered in the tests.

Two rectangular reinforced concrete beams were tested to pilot further investigations: one with normal concrete mix of $\text{1:2:4}$ and the other with the concrete $\text{1:1}\text{1}\text{2}\text{:3}$ with soft laterite as fine aggregate instead of sand. The ultimate moments of resistance of the two beams are almost the same although the beam of normal concrete offers greater flexural rigidity throughout, and deflexions of the beam with $\text{1:1}\text{1}\text{2}\text{:3}$ mix with laterite fines deflected about twice as much as the normal concrete beam of $\text{1:2:4}$ mix prior to the appearance of flexural cracks in both beams. The phenomenon still requires further investigation. The effect of creep on various types of structural elements cast with the concrete containing laterite fines instead of sand will need to be studied before concluding on suitability of the material for structural work.