Reinforcing concrete: comparison of filler effects

Abstract

We have applied six different fillers to a typical polymer cement. Silica fume, furnace slag, fly ash, marble powder, natural sand and boron were used at different percentages mixed in a commercial epoxy. The concentration of the fillers varied from 10 to 50 wt.% at 10% intervals. The composites were subjected to 3-point bending and compression testing. Weight loss of each sample was evaluated in a hydrochloric acid bath. There are differences in densities or weights of the samples that need to be taken into account when considering mechanical parameters. Boron and fly ash powders provide flexural strength determined by 3-point bending higher than the neat epoxy. Some fillers lower the flexural strength of the cement, a result of the filler agglomeration. Fly ash, furnace slag and boron increase the elastic modulus in compression; so does also silica fume but only at 30 wt.% concentration. Marble powder has a small negative effect on the compressive modulus while natural sand has little effect. However, when one takes into account densities or specific weights, only 10% boron enhances the compressive performance per unit weight. Weight losses in hydrochloric acid solutions are the largest for natural sand (13 wt.%), for boron up to 11%, for marble powder up to 8%, for furnace slag also near 8%. Silica fume and fly ash have the changes below 1.8%.