title: Use of limestone powder during incorporation of Pb-containing cathode ray tube waste in self-compacting concrete.
abstract: For several decades, cathode ray tubes (CRTs) were the primary display component of televisions and computers. The CRT glass envelope contains sufficient levels of lead oxide (PbO) to be considered hazardous, and there is a need for effective methods of permanently encapsulating this material during waste disposal. We examined the effect of adding limestone powder (LS) on the fresh and cured properties of self-compacting concrete (SCC) mixtures containing waste CRT glass. The SCC mixtures were prepared using Type 1 Portland cement at a constant cement content of 600 kg/m(3) and a water-to-cement ratio (w/c) of 0.38. CRT glass waste cullet was blended with river sand in proportions of 20 or 40% by weight. To suppress potential viscosity effects limestone powder was added at levels of 5, 10, or 15% by weight. The slump flow time, slump flow diameter, V-funnel flow time, Marsh cone flow time, and setting time of the fresh concrete were tested, as well as the compressive strength and ultrasonic pulse velocity of the hardened concrete. Addition of limestone powder improved the fresh and hardened properties. Pb leaching levels from the cured concrete were within US EPA allowable limits.
authors.affiliation: Department of Building Technology Faculty of Industrial Technology, Phranakhon Rajabhat University, 9 Changwattana Road, Bangkhen, Bangkok 10220, Thailand.
authors.forename: Gritsada
authors.initials: G
authors.lastname: Sua-iam
authors.forename: Natt
authors.initials: N
authors.lastname: Makul
mesh_terms: D002119:Calcium Carbonate; D055984:Cathode Ray Tube; D019245:Compressive Strength; D003247:Conservation of Natural Resources; D003252:Construction Materials; D004867:Equipment Design; D007854:Lead; D008855:Microscopy, Electron, Scanning; D012037:Refuse Disposal / Q000295:instrumentation / Q000379:methods*; D012822:Silicon Dioxide; D013010:Sonication; D013696:Temperature
chemical_list: D007854:Lead; D012822:Silicon Dioxide; D002119:Calcium Carbonate
keywords: Cathode ray tube (CRT); Fine aggregate; Limestone powder; Pb immobilization; Self-compacting concrete