Concrete Resistance Achieved with Subtly Ground Tube Glass of Cathode Ray as Supplementary Cementitious Material to Sulphate Attack
One of the essential requirements in modern civil engineering is a sustainable building, with the aim of reducing the harmful impact on the environment. Since the early XXI century, usage of recycled materials has been insisted on, which could, at least partly, substitute traditionally used materials. Although there is no serial manufacturing of TV sets with cathode ray tubes anymore, piles of cathode ray tube glass (CRT) at the waste disposal sites have still been on the increase. This experimental research was supposed to determine the potential for using subtly milled CRT glass as a supplementary cementitious material and to check the resistance of similar concretes to the sulphate action. Six testing concrete batches were made. The percentage of cement replacement percentage with CRT was: 5%, 10%, 15%, 20% and 35%, by mass. Durability assessment of concrete to sulphate action was done by visual estimation of concrete appearance as well as through testing the compressive strength variations of treated concrete specimens 3, 6, 12 and 36 months old. After soaking the specimens in a 5% solution of Na2SO4 for 36 months, concretes with 15% to 20% of replaced cement with finely ground CRT glass have simultaneously satisfactory compressive strength and resistance to sulfate attack. In this sense, this range of replacement of cement with finely ground CRT glass can be recommended for practical application.