Influence on an impervious membrane beneath concrete slabs on grade

Recommended housing practice in Australia is to cast concrete for floor slabs on polythene sheeting. Recent American findings suggest that for unreinforced concrete slabs this practice leads to inferior performance. Laboratory studies of companion slabs cast on free draining and impervious bases indicate that the latter base type leads to retention of mixing water within the concrete and that this factor plays a highly significant part in determining the behaviour of the slab. When compared with identical concrete cast on a draining base, concrete cast on an impervious base has higher dimensional changes in the plastic state, during drying shrinkage and when subjected to environmental changes. It also has lower flexural and compressive strengths and lower modulus of elasticity. Slabs cast on polythene are also considered to be more prone to plastic settlement cracking, although plastic shrinkage cracking is likely to be reduced. Data is presented illustrating these effects and the mechanisms of the observed phenomena and their relationships to practice are discussed. Recommendations concerning the use of impervious and draining bases beneath concrete slabs are made (a).


  • English

Media Info

  • Pagination: 51-61
  • Monograph Title: Symposium on concrete for engineering; engineering for concrete, Brisbane, 1977; papers
  • Serial:
    • Issue Number: 77/8

Subject/Index Terms

Filing Info

  • Accession Number: 01441046
  • Record Type: Publication
  • Source Agency: ARRB
  • ISBN: 0858250845
  • Files: ATRI
  • Created Date: Aug 24 2012 11:21PM