The patchy structure of cement paste in conventional concretes

Title: The patchy structure of cement paste in conventional concretes
Author(s): Sidney Diamond
Paper category : conference
Book title: International RILEM Symposium on Concrete Science and Engineering: A Tribute to Arnon Bentur
Editor(s): J. Weiss, K. Kovler, J. Marchand, and S. Mindess
Print-ISBN: None
e-ISBN: 2912143926
Publisher: RILEM Publications SARL
Publication year: 2004
Nb references: 4
Language: English

Abstract: It has been found that the hardened cement paste (hcp) in some conventionally-mixed concretes examined in backscatter-mode scanning electron microscopy (SEM) contains areas or patches that are uniformly dense and easily distinguished from nearby areas or patches that are coarsely porous. Such distinct dense and porous patches have been found both in laboratory mixed concretes and in commercial ready-mix concretes installed in various structures. Some of the porous hcp patches may run parallel to and be adjacent to some aggregate surfaces, but nearby dense patches without visible porosity generally abut other aggregate surfaces. The porous patches may contain both hollow shells derived from Hadley grain formation and irregular and interconnected capillary pores. The area proportion of porous to dense patches appears to be progressively higher for concretes of progressively higher w:c ratios, and dense areas are only rarely encountered in concretes of w:c ratios of ca. 0.8.

Online publication: 2004-03-25
Publication type : full_text
Public price (Euros): 0.00
doi: 10.1617/2912143926.107