Silicates-based concrete resists acids

Citation

(1999), "Silicates-based concrete resists acids", Anti-Corrosion Methods and Materials, Vol. 46 No. 1. https://doi.org/10.1108/acmm.1999.12846aab.001

Silicates-based concrete resists acids

Silicates-based concrete resists acids

Keywords Concrete, Corrosion, Zeotech

Zeotech Corp. (Cherry Hill, New Jersey) has developed a pre-cast concrete that it claims is highly resistant to acids and corrosion. In 365-day tests, samples were unaffected by immersion in 20 percent sulphuric acid, 5 percent sulphuric acid and 20 percent nitric acid, the company says. Samples of ordinary concrete totally disintegrated.

The key ingredient is the binder, an inorganic form of sodium silicate. Its backbone is repeated units of O-Si-O-Al, with significant amounts of branching, forming what amounts to an acid-resistant ceramic. When mixed with aggregate (sand and stone)and flyash, it creates a natural zeolite material with the look, feel and strength of concrete, and the acid-resistance of glass, says Anthony Oswald, vice-president of sales and marketing.

Standard concrete (Portland cement and aggregate) contains calcium, which reacts with acid. There are various ways to impart acid-resistance, but they are generally expensive and most offer only temporary protection. Oswald says Zeotech's concrete can be made with standard equipment, at a cost that is competitive with that of conventional protective-coated concrete.