LABORATORY INVESTIGATION OF COMPACTED NO-FINES CONCRETE FOR PAVING MATERIALS

In this study the physical and engineering characteristics of various no-fines concrete mixtures are investigated. No-fines concrete mixture s subjected to impact compaction are studied under unconfined compress ion, indirect tension, and static modulus of elasticity; and the resul ts are interpreted as functions of mixture proportions. The effect of impact-compaction energies, consolidation techniques, mixture proporti ons, curing types, and testing conditions on physical and engineering properties are presented. The abrasion characteristics and resistance to freezing and thawing of no-fines concrete are also discussed. It wa s found that the strength of no-fines concrete is strongly related to its mixture proportion and compaction energy. A sealed compressive str ength of 20.7 MPa (3,000 psi) can readily be achieved with an aggregat e cement ratio of 4.5:1 or less and a minimum compaction energy of 165 J/m(3) (4,303 ft-lb/cu ft). The splitting tensile-compressive relatio nship followed a pattern similar to that of conventional concrete. No- fines concrete had a lower modulus of elasticity than conventional con crete. The ultimate drying shrinkage of compacted no-fines concrete wa s found to be approximately 280 x 10(-6), about half that typically ex pected in conventional concrete. Air-entrained no-fines concrete exhib ited a higher resistance to freezing and thawing than non-air-entraine d mixtures.