Abstract
Gypsum blocks are usually used to make partitions in highrise construction. Reducing the cost of materials used in high-rise construction is an urgent task of modern material science. Phosphogypsum dihydrate, which has binding properties, is one of the large-tonnage waste. The authors have proved that, after years of storage in heaps, water-soluble phosphates, fluorides and other additives included in the structure of fresh phosphogypsum dissolved in water due to weathering (humidification-drying, freezing-thawing in a water-saturated state), and the calcium hydro-and dihydrogen phosphates ingressed in the lattice underwent complete hydrolysis and disintegration, thereby changing the physicochemical properties of phosphogypsum. The data obtained by the authors on the absence of water-soluble compounds of phosphorus, fluorine in stale phosphogypsum indicate its ecological purity and the possibility of application in housing construction. Having analyzed the data of modern methods of differential scanning calorimetry and scanning electron microscopy, the authors predicted and proved by the energy of dehydration of phosphogypsum dihydrate, lime, sandy loam, the possibility of obtaining non-flammable materials with sufficient strength for wall materials. Understanding the processes occurring in water films (the thickness of the water film, the pressure, the temperature and the pH of the aqueous extract of the mixture, the drying of the materials produced), made it possible to develop a technology for obtaining wall products from lime-sandy phosphogypsum material using typical silicate brick production equipment and vibropresses for key-cog blocks production.
Highlights
In mass construction of high-rise buildings, partitions made of gypsum blocks are widely used
Previous studies [4] have shown that water films, self-organizing according to the usual technologies of preparation of mortars, stabilize at the thicknesses equal to 1·10-7 m, and the maximum strength parameters in the obtained materials can be reached at the thicknesses 1·10-7 m>Δ>1·10-9 m, so to reduce the thickness of the water films, it is necessary to bring the mineral components closer, which can be achieved by pressing or drying the resulting composites
After years of storage in heaps, the water-soluble phosphates, fluorides and other additives included in the structure of fresh phosphogypsum dissolved in water due to weathering, and the calcium hydro- and dihydrogen phosphates ingressed in the lattice underwent complete hydrolysis and disintegration, thereby changing the physicochemical properties of phosphogypsum
Summary
In mass construction of high-rise buildings, partitions made of gypsum blocks are widely used.
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