The effects of sodium silicate on corn cob aggregates and on the concrete obtained with these agricultural waste

In order to protect the environment and to reduce its pollution, the concrete greening is an important objective to accomplish this goal. Research across the world has expanded to replace some components of concrete with different kinds of alternative ecological materials, including agricultural materials that are readily renewable resources. They may partially replace the mineral aggregates, if they are used in a shredded form, and / or the cement from the concrete composition, if the ash resulting from their combustion is used. When used as an alternative of mineral aggregates, plant aggregates generally have a number of disadvantages, which requires finding a solution which reduces their water absorption, improves the interface between them and the cement matrix, and gives them durability in the resulting concrete. The present study investigated the effect of sodium silicate on plant aggregates made of shredded corn cobs, and on the concrete manufactured with this type of material as a replacement of mineral aggregates by 20%, 50% and 80% by volume. Experimental results revealed that sodium silicate reduced the water absorption of the grounded corn cobs, resulting a lightweight concrete with improved compressive and tensile strength compared to those of the concrete manufactured with untreated plant aggregates. The use of sodium silicate as a concrete additive resulted in an increase of the compressive strength of the concrete manufactured with 50% by volume corn cob aggregates, of the splitting strength in the case of concrete with 20% and 80% by volume vegetal aggregates, and of the density of the concrete manufactured with the highest percentages of plant aggregates which were investigated in this study.