Water absorption in cover concrete

Measurements of initial water absorption are reported for concretes exposed indoors or outside for 1.5 years. Water absorption after a given wetting time was increased with an increase of water/cement ratio, a reduction of moist curing and partial replacement of the Portland clinker component of the cement. Absorption after outdoor exposure was less than that after laboratory exposure, especially if rain could fall on the concrete surface. Absorption results correlated approximately with weight losses during initial exposure and with compressive strengths at the start of exposure. There was a near-linear relationship between carbonation depths and absorption measured in cover concrete after 1.5 years of exposureResumeOn rend compte de mesures de l'absorption d'eau initiale sur des bétons exposés pendant 18 mois en milieu fermé et en plein air. Après un temps donné d'humidification, l'absorption d'eau augmentait avec l'accroissement du rapport eau/ciment, la diminution de la conservation à l'état humide et le remplacement partiel du composant de clinker Portland du ciment. A la suite de l'exposition à l'air libre, l'absorption, en particulier si la pluie était tombée sur la surface du béton, était moindre qu'en laboratoire. Les résultats de l'absorption correspondaient approximativement avec les pertes de poids durant l'exposition initiale, et aux résistances en compression au début de l'exposition. On a constaté une relation non linéaire entre les profondeurs de carbonatation et l'absorption mesurées dans le béton d'enrobage après une exposition de 18 mois.

[1]  C. F. Scholer,et al.  A New Approach for Testing Concrete Curing Efficiency , 1984 .

[2]  W. D. Hoff,et al.  Unsaturated water flow within porous materials observed by NMR imaging , 1979, Nature.

[3]  L. Parrott.  Measurement and Modeling of Porosity in Drying Cement Paste , 1986 .

[4]  C. Hall,et al.  Water sorptivity of mortars and concretes: a review , 1989 .

[5]  D.W.S. Ho,et al.  The specification of concrete for reinforcement protection— performance criteria and compliance by strength , 1988 .

[6]  Massud Sadezadeh,et al.  Indirect and non-destructive methods for assessing abrasion resistance of concrete , 1986 .

[7]  Christopher Hall,et al.  The sorptivity of brick: dependence on the initial water content , 1983 .

[8]  R. J. Torrent,et al.  THE QUALITY OF THE 'COVERCRETE' OF LOW-, MEDIUM- AND HIGH-STRENGTH CONCRETES. IN: DURABILITY OF CONCRETE. SECOND INTERNATIONAL CONFERENCE. AUGUST 4-9, 1991, MONTREAL, CANADA. VOLUME II , 1991 .

[9]  L. J. Parrott,et al.  Factors influencing relative humidity in concrete , 1991 .

[10]  G. Osborne,et al.  A comparison of the properties of OPC, PFA and ggbs concretes in reinforced concrete tank walls of slender section , 1990 .

[11]  P B Bamforth,et al.  MINIMISING THE RISK OF CHLORIDE INDUCED CORROSION BY SELECTION OF CONCRETING MATERIALS. CORROSION OF REINFORCEMENT IN CONCRETE. PAPERS PRESENTED AT THE THIRD INTERNATIONAL SYMPOSIUM ON "CORROSION OF REINFORCEMENT IN CONCRETE CONSTRUCTION", BELFRY HOTEL, WISHAW, WARWICKSHIRE, MAY 21-24, 1990 , 1990 .

[12]  R. K. Dhir,et al.  Near-surface characteristics of concrete : assessment and development of in situ test methods , 1987 .

[13]  L. J. Parrott,et al.  Moisture profiles in drying concrete , 1988 .

[14]  S. Kelham,et al.  A WATER ABSORPTION TEST FOR CONCRETE , 1988 .

[15]  P. C. Kreijger.  INHOMOGENEITY IN CONCRETE AND ITS EFFECT ON DEGRADATION: A REVIEW OF TECHNOLOGY . PROTECTION OF CONCRETE. PROCEEDINGS OF THE INTERNATIONAL CONFERENCE HELD AT THE UNIVERSITY OF DUNDEE, SEPTEMBER 11-13, 1990 , 1990 .