Early volume changes of high performance self-compacting cementitious systems containing pozzolanic powders

Title: Early volume changes of high performance self-compacting cementitious systems containing pozzolanic powders
Author(s): Syed Ali Rizwan, Thomas A. Thomas A. Bier
Paper category : conference
Book title: International RILEM Conference on Volume Changes of Hardening Concrete: Testing and Mitigation
Editor(s): O. M. Jensen, P. Lura, K. Kovler
Print-ISBN: 2-35158-004-4
e-ISBN: 2351580052
Publisher: RILEM Publications SARL
Publication year: 2006
Pages: 283 - 292
Total Pages: 10
Nb references: 17
Language: English

Abstract: This study is an ongoing investigation by the authors on high performance (HP) self compacting cementitious systems (SCCS) and addresses early volume changes of cementitious systems using inert and pozzolanic powders. The systems investigated had secondary raw materials (SRM) including limestone powder (LSP-relatively inert) and pozzolanic materials like fly-ash (FA), rice-husk ashes (RHA’s both amorphous and crystalline) and as produced powder type silica fume (SF). Locally available natural sand (0-2 mm size fraction-S1) was used. Such systems were generally studied for linear early shrinkage in two exposure conditions in the laboratory wherein constant temperature and humidity conditions were maintained.
The results on HP SCPs (self-compacting paste systems) indicate that incorporating powdered super plasticizer (SP) reduced the shrinkage. Covering a formulation also did the same. At higher water-cement ratios shrinkage got reduced due to dilution effect. Regarding HP SCM systems using LSP, the early uncovered shrinkage remains almost the same for all the cements used in both exposure conditions. FA system showed expansion in covered condition with all cements. The shrinkage of such system got reduced when 20% RHA was incorporated into it. However, 20% addition of RHAP (crystalline) in FA gave a higher expansion in covered conditions with all cements compared with 100% FA system. MIP studies showed comparable pore refinement effect of SF and RHA. It is also shown that suitable binary and ternary binders when used in an appropriate way could reduce early shrinkage of HP SCCS, increase strength and improve microstructure.

Online publication: 2006-07-30
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2351580052.030