Application of foundry by-product materials in manufacture of concrete and masonry products

This research was undertaken to evaluate the performance of foundry byproducts in concrete and masonry products. Two series of experiments were carried out. The first series of experiments were directed toward the use of an air-cooled foundry slag in concrete as a partial replacement of coarse aggregate. The second series of work involved the use of foundry sand as a partial replacement of fine aggregate for making masonry blocks and paving stones. The first series of rests were carried out to evaluate the performance characteristics of a foundry slag concrete under laboratory conditions. A reference concrete without foundry slag was proportioned to obtain a 28-day compressive strength of 6000 psi. Two other mixes containing 50 and 100 percent foundry sing as a replacement of regular aggregate were also proportioned. The 100 percent sing mix showed compressive strength comparable to the reference mix. However the modulus of elasticity of concrete containing 100 percent slag was higher than the reference concrete. Four mixes with and without foundry sands were proportioned for the manufacture of masonry blocks with a design strength of 1500 psi at the 28-day age. Additionally, four mixes, three with and one without foundry sands, were also proportioned for the manufacture of paving stones with a design strength of 8000 psi at the 28-day age. ln all of the the mixes, 35 percent regular sand was replaced with new/used foundry sand obtained from different sources; no admixtures were added to the mixes. Test results indicated that masonry blocks made with 35 per cent used foundry sand passed the ASTM requirements for compressive strength, absorption, and bulk density. However the paving mixes used in this study did not meet tile target strength of 5000 psi and showed slightly higher absorption than the ASTM limit for paving stones.