Specialists from Kazan State University of Architecture and Engineering (KSUAE) have patented a new method for preparing concrete mix that allows for the utilization of chemical water treatment sludge while increasing the strength of the material. The technology involves processing the components in a vortex layer apparatus with a magnetic field, according to the patent.
The composition of the mixture includes Portland cement, a water repellent, sludge (water treatment waste from thermal power plants), coarse and fine aggregate. The secret of the technology lies in the pre-treatment. Sludge and water repellent are loaded into an installation with a powerful magnetic field. There, they are activated for 7–10 minutes. After that, the mixture is stirred in a concrete mixer with water for at least five minutes.
The ratio of components is selected to maximize the use of waste without losing quality. As a result, the concrete shows high strength: up to 32.7 MPa in the first day of hardening, and up to 88.2 MPa on the 28th day: this is almost a ton of force per square centimeter. Ordinary M300 concrete, which is most often used in construction, withstands about 300 kg/cm² — the new material is almost three times stronger.
Such strength may be needed for particularly critical structures: high-rise buildings, bridges, dams, military facilities, and bunkers. The technology allows for the simultaneous utilization of industrial waste and the production of material with improved characteristics.