Feasible use of recycled CRT funnel glass as heavyweight fine aggregate in barite concrete

The challenge of managing discarded cathode ray tube (CRT) waste has become a major environmental concern in Hong Kong and other cities. Recycled CRT funnel glass with a relatively high density (∼3000 kg m-3) can be used as a potential material for the production of heavyweight concrete. This paper presents the results of an investigation on the feasibility of using recycled CRT funnel glass, both treated (lead has been removed from the glass surface) and untreated (without removal of lead) as partial and full replacements of fine aggregates in heavyweight barite concrete. The inclusion of barite aggregate and recycled funnel glass increased the hardened density but reduced the compressive and splitting tensile strengths. The replacement of natural fine aggregate with recycled CRT glass had no significant effect on the elastic modulus but considerably improved the drying shrinkage of the concrete. In conclusion, the overall properties of heavyweight barite concrete made with the treated and untreated recycled CRT funnel glass are comparable, except for lead leaching results. The results show that it is feasible to use the treated CRT glass as 100% substitution of fine aggregate in making heavyweight concrete. However, the substitution of untreated glass should be limited to below 25% due to its potential lead leaching.