INITIAL CRACKING OF ROAD CONCRETE /IN FRENCH/
IT SOMETIMES HAPPENS THAT A CONCRETE PAVEMENT CRACKS DURING THE FIRST FEW DAYS AFTER IT HAS BEEN LAID, BEFORE BEING SUBJECTED TO TRAFFIC. THIS CRACKING HAS A TWIN ORIGIN: IT IS RELATED TO HYGROMETRIC AND THERMAL SHRINKAGE. HYGROMETRIC, OR DRYING, SHRINKAGE IS IMPORTANT, BECAUSE IT VERY RAPIDLY AFFECTS THE MASS OF THE PAVEMENT; BUT WHEN THE CONCRETE IS PROPERLY PROTECTED AGAINST EVAPORATION, THERMAL SHRINKAGE BECOMES THE MAIN CAUSE OF CRACKING. THE INCREASE IN THE INTERNAL TEMPERATURE OF THE PAVEMENT DURING THE FIRST FEW HOURS IS DUE TO EXOTHERMIC SETTING REACTIONS. THE REDUCTION OF THE INTERNAL TEMPERATURE DEPENDS ON THE MORE OR LESS SUDDEN STOPPAGE OF THE SETTING REACTIONS AND ON THE ENVIRONMENT OF THE PAVEMENT. THE AMBIENT TEMPERATURE DOES NOT SEEM TO BE ONE OF THE MOST IMPORTANT FACTORS INFLUENCING THE INTERNAL TEMPERATURE OF THE PAVEMENT. WHEN AN ISOLATED CRACK APPEARS, ITS CAUSE CANNOT BE FOUND AMONG THE FACTORS WHICH INFLUENCE THERMAL OR DRYING SHRINKAGE. AS A RULE IT HAS AN ACCIDENTAL CAUSE RESULTING FROM THE HAZARDS OF CONCRETE PRODUCTION OR OF THE LAYING OF THE PAVEMENT. IN ORDER TO REDUCE THE RISKS OF CRACKING ON A CONSTRUCTION SITE, IT IS ADVISABLE TO CHOSE WITH CARE THE AGGREGATES AND THE CEMENT USED, AND TO MAKE SURE THAT PRODUCTION AND LAYING ARE REGULAR. /LCPC/A/RRL/
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Supplemental Notes:
- No 26, pp 4-16, 10 FIG, 3 TAB, 9 REF
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Authors:
- Brachet, M
- Baron, J
- Publication Date: 1967-7
Media Info
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Serial:
- Bull Liaison Labs Routiers /France/
- Publisher: Laboratoire Central des Ponts et Chausees (LCPC)
Subject/Index Terms
- TRT Terms: Aggregates; Cement; Concrete; Concrete curing; Concrete pavements; Cracking; Humidity; Measurement; Shrinkage; Temperature
- Uncontrolled Terms: Concrete cracking
- Old TRIS Terms: Hygrometry
- Subject Areas: Construction; Geotechnology; Highways;
Filing Info
- Accession Number: 00214878
- Record Type: Publication
- Source Agency: Road Research Laboratory /UK
- Files: TRIS
- Created Date: Nov 23 1970 12:00AM