Performance and leaching assessment of flowable slurry

This project was conducted to evaluate the performance and leaching of cont rolled low strength materials (CLSM) incorporating fly ash and foundry sand . Two different CLSM (or flowable slurry) reference mixtures (equivalent to available production CLSM mixtures) were proportioned for unconfined compr essive strength levels in the range of 0.3-0.7 MPa (50-100 psi), at 28 days , using two sources of ASTM Class F fly ash. For each reference mixture, ot her mixtures were proportioned using two sources of foundry sand (molten me tal-casting mold sand) as a replacement for fly ash in the range of 30-85%. The ingredients of the slurry mixtures-fly ash, clean foundry sand, and us ed foundry sand-were tested for their physical and chemical properties and their leachate characteristics. Portland cement used as the primary binder was also tested for its properties. All CLSM mixtures made with and without foundry sand were evaluated for settlement, setting and hardening characte ristics, compressive strength, permeability, and leachate characteristics. The leachate results of these CLSM-making materials were below the enforcem ent standards (ES) of the Wisconsin Department of Natural Resources (WDNR) ground-water quality standards (GWQS). They also met practically all the pa rameters of the drinking water standards. A number of CLSM mixtures incorpo rating fly ash and foundry sand ate recommended for construction applicatio ns.