Properties of mortar for self-compacting concrete
The effect of types and amount of powder materials, admixtures, sand and water content on the properties of self-compacting concrete (SCC) have been investigated by tests on the mortar fraction. Tests on concrete have also been a carried out to confirm the most important effects. The component materials used were * eight types of powder- PC and SRC, GGBS, PFA, CSF and three types of LSP, * six superplasticizers -a naphthelene (Conplast 430) and melamine type, two copolymers, one polycarboxylic ether (Glenium 51) and one formulated for S CC, * two viscosity agents - Welan gum and a cellulose product , * one fine and coarse aggregate, generally at volumetric proportions of 40-47.5% of the mortar and 31.7% of the concrete respectively. Testing has concentrated on workability and workability retention of mixes with a single powder, binary and ternary powder combinations, with and without a viscosity agent. Tests have included spread/slump flow, V-funnel flow time, and two-point workability tests for mortar and concrete, a U-box test for concrete, and some strength tests on concrete. The most important outcomes include: * Glenium 51, the most efficient superplasticizer, was selected for most of the programme, added at 1 minute after the start of mixing. * Excellent workability and workability retention was obtained in binary and ternary mixes containing CSF, and in SRC single powder mixes. * Yield stress and plastic viscosity are two distinct and independent properties. * Welan gum has better compatibility with Conplast 430 than Glenium 5l; its use improved workability retention but slightly decreased strength. * There are strong relations between the properties of concrete and its mortar component, and the rheological constants and single point test results for mortar and concrete. * The rheology of some mortar mixes may be better described by the Herschel- Bulkley model than by the Bingham model.