Impact crushing of concrete for liberation and recycling

A test rig (large-scale pneumatic cannon) has been designed, constructed an d tested. This apparatus allows the adjustment of intensive stressing condi tions, e.g., impact and double impact, single and multiple stressing, veloc ity and energy. The accelerating tube diameter limit was given by the condi tion of a representative feed sample (model concrete spheres 150 mm sample diameter Limited by an upper particle size of aggregate d(o) = 16 mm). The crushed fragments are described as subcollectives (truncated logarithmic no rmal distributions) of a multimodal distribution function. For impact stres sing, liberation grades between 0.3 and 0.6 (0% adherent hardened cement pa ste) as well as more than 0.9 (0-50% adherent hardened cement paste) were o btained. (C) 1999 Elsevier Science S.A. All rights reserved.