Development of self-consolidating concrete for slip form paving
"In this study, a new type of self-consolidating concrete for slip-form paving (SF SCC) was developed. Effects of materials and mix proportions on fresh concrete compact-ability, flow-ability, and shape stability were studied. Type I cement and class C and F fly ashes were used as cementitious materials. Air-entraining agent (AEA), viscosity modifying admixture (VMA), and superplasticizer were employed as admixtures. Normal river sand and limestone were utilized as aggregate. A total of 46 concrete mixes were studied, and non-rodding slump flow test, modified compaction factor test, IBB rheometer test, and ""green"" strength tests were performed for the concrete mixtures. In addition, a ""mini-paver"" was developed to simulate the field SF SCC paving in laboratory. The study has demonstrated that by engineering concrete materials and mix proportions, it is feasible to develop a new type of SCC for slip form paving application. Concrete mixtures having a compaction factor of approximate 1.0, slump of approximated 8"", and spread of approximated 12"" displayed not only to be able to self-compact but also to hold its shape right after placement. The test results also indicated that concrete compactibility increased but stability decreased with flow-ability. There was a nonlinear relationship between slump and spread for the concrete mixtures tested. The interception obtained from the IBB tests (similar to yield stress of the mixtures) had a good relationship with not only slump but also ""green"" strength of concrete."