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This paper studies the role of C[O.sub.2] treatment and the impact of particle size ( Key words: waste cement powder, C[O.sub.2] treatment, particle size, calcite, compressive strength, microstructure. Dans le cadre de cet article, on etudie le role du traitement au C[O.sub.2] et l'impact de la taille des particules (< 75 [micro]m et 75-150 [micro]m) de residu de poudre de ciment (RPC) avec differentes teneurs en ciment de remplacement (0, 5,10,15, 20 et 30 %) sur les proprietes physiques et la microstructure de la pate de ciment melangee. Les resultats montrent que la carbonatation du RPC peut effectivement augmenter la fluidite de la pate due a la formation de calcite et diminuer la porosite de la microstructure du RPC, tandis que la demande d'eau pour atteindre la meme maniabilite diminue avec la taille croissante des particules de RPC. La pate de ciment contenant moins de particules de residu de poudre de ciment carbonatee possede une plus haute resistance a la compression a 28 jours en raison de la formation d'une plus grande quantite de produits de calcite et d'hydratation, selon l'analyse thermogravimetrique. [Traduit par la Redaction] Mots-cles : residu de poudre de ciment, traitement au C[O.sub.2], taille des particules, calcite, resistance a la compression, microstructure., 1. Introduction One of the main environmental concerns presently is pollution caused by the vast volume of industrial wastes, especially construction waste, generated around the world. Every year, nearly 20 [...]

RECYCLING ALUMINUM FOR EV PARTS An innovative manufacturing process that collects and transforms scrap aluminum directly into new vehicle parts was unveiled by collaborators from the DOE's Pacific Northwest National [...]

This study was conducted to assess the effect of traditional and industrial waste materials approved for road construction on the surrounding environment and adjacent water bodies. A list of construction and maintenance materials was selected for this investigation based on their wide use and information extracted from their material safety datasheets. A toxicity-based approach was employed as an effective way of screening the toxicity of the selected materials. Toxicity tests using algae and Daphnia were conducted to determine the level of toxicity in water elutriates prepared from the selected materials that emulate storm water runoff. Many of the tested construction materials proved to be toxic to the test organisms. Heavy metals such as aluminum, arsenic, lead, and mercury and some hydrocarbon compounds present in test elutriates appeared to be major causes of toxicity. However, measured toxicity was significantly reduced or eliminated when elutriates were allowed to be in contact with selected soils. Under actual field conditions, mechanisms other than soil sorption such as volatilization, photolysis, and biodegradation are believed to further reduce the toxicity of storm water runoff. DOI: 10.1061/(ASCE)0733-9372(2002)128:5(423) CE Database keywords: Construction materials; Toxicity; Highway construction; Construction methods.

An overview is presented on producing clean burning ethanol fuel from organic residuals, and its positive impact on energy security and economic development. Nationwide adoption of this process can divert 75% of landfill-bound materials to energy production and other marketable products.

The Atlantic Richfield Products Company located in Blaine, Wash. generates about 6,356 Mg (7,000 tons) of coke dust every year. The coke dust is produced during the process of calcination in the hearths, storage silos, conveyor systems, and during the loading process into rail cars. The main objective of this research study is to investigate the potential use of calcined and green coke (uncalcined) dusts as modifiers in hot mix asphalt paving mixtures. Six different blends including control were subjected to binder testing and grading using Superpave testing equipment and procedures. Hveem mix designs also were conducted on the six mixtures. Coke dust was added by total weight of the asphalt cement binder. Research results indicate that both coke dusts will act as reinforcing agents for the asphalt cement binders. Both coke dusts seem to improve asphalt cement performance (high stiffness) at high temperatures (58 and 64 [degrees] C) with minimal adverse effect (increased stiffness) at low temperatures (-12 and -18 [degrees] C). At intermediate temperatures, penetration values at 25 [degrees] C will decrease and dynamic shear values at 19 and 22 [degrees] C generally will increase as a result of coke dust addition. Viscosity (stiffness), dynamic shear, Hveem stability, and voids in mineral aggregate tend to increase as a result of adding coke dust (whether it is calcined or green). Also, there is a slight improvement in retention of asphalt coating when coke dust is used. All mixtures exceeded the minimum Washington State Department of Transportation specification requirements for class B hot mix asphalt concrete. Thus, if proper aggregate is used, permanent deformation (rutting) and stripping will be reduced in coke dust - modified asphalt pavements.

Byline: Alok Mittal, Rajiv Jain, Jyoti Mittal, Shaily Varshney, Shalini Sikarwar Attempts have been made to remove toxic dye Yellow ME7GL using electrochemical and adsorption techniques. Both techniques are capable of reducing toxicity and producing clean water for reuse. The electrochemical removal is carried out at platinum electrode and cyclic voltammograms of the dye solutions have been recorded at different pH, concentrations, scan rates, etc. The adsorption of the dye has been carried out over activated charcoal and wheat husk and verified by Langmuir and Freundlich adsorption isotherms. The decolouration of the dye was also examined by monitoring the Chemical Oxygen Demand (COD) of the untreated and treated dye solutions.

An overview is presented on the use of industrial waste in a variety of composting and other soil amendment applications. These include causticizing wastes as substitutes for agricultural lime, pharmaceutical residues for high-nitrogen treatments, and paper fiber as a component of engineered soil for covering mine-refuse piles.