Application of the Grey System Theory to Predict the Strength Retrogression of Concrete with Gangue Subjected to Corrosion by Sulphate

Concrete with gangue which made with ordinary Portland cement at different water binder ratio (0.35, 0.40 and 0.45) or ordinary Portland cement at water binder ratio of 0.35 incorporating 10% fly ash or 20% fly ash; 20% fly ash and 1% early strength agent, slag with the replacement of 15% or 30%, or 15% fly ash and 15% slag were made and exposed to a wetting–drying sulfate environment. The compressive strength of the specimens of concrete with gangue was measured. The effects of sulfate concentration, water-binder ratio, mineral admixtures and chemical additives on the compressive strength of the concrete were studied through the grey relational analysis. Grey prediction model was established to predict the strength development of the concrete with gangue subjected to sulfate environment. The results indicate that the importance degree of these effective variables from high to low is ranked according to water-binder ratio, solution concentration, test age, fly ash content, slag content, early strength agent content. Producing curbstone with coal gangue concrete conform to the requirements of the specification because its physical properties superior than normal concrete and the properties of antifreeze and sulfate attack resistance can meet the requirements of the municipal engineering. It can be found that not only significantly reduce costs and save raw materials, can also achieve waste recycling through the engineering application. So it can be obtained social and economic benefits. The grey prediction model shows enough precision to predict the strength development of the concrete with subjected to corrosion by sulphate.