Effect of cracking and healing on chloride transport in OPC concrete

Journal Article · Sat Jun 01 04:00:00 EDT 1996 · Cement and Concrete Research

DOI:https://doi.org/10.1016/0008-8846(96)00072-5· OSTI ID:276761

Jacobsen, S ^[1]; Marchand, J; Boisvert, L ^[2]

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1. Norwegian Building Research Inst., Oslo (Norway)
2. Univ. Laval/CRIB, Quebec (Canada)

The effects of cracking and self healing on chloride migration and compressive strength were investigated on w/c = 0.40 concrete. Internal cracking due to rapid freeze/thaw exposure resulted in a compressive strength reduction of 68--40% and a reduced Ultrasonic Pulse Velocity (UPV) to 78--45% of undamaged values. The rate of chloride migration through 15 mm thick slices under a 10 volt electric field was increased by 2.5--8 times, and the chloride penetration time through the slices was reduced from 64 to 0 hours for the most severe cracking. The increased chloride transport due to cracking could be predicted fairly well by characterizing the cracks using a square grid crack pattern model. Self healing by storage of cracked specimens in lime saturated water at 20C for three months after stop of freeze/thaw exposure gave recovery in UPV of 50--100%, but compressive strength recovered only 0--10% of the initial value. Rate of chloride migration in the self-healed concretes was reduced by 28--35%, and penetration time was increased compared to newly cracked concrete. The chloride migration through an air entrained concrete with the same w/c ratio (no internal cracking after more than 300 cycles of rapid freeze/thaw exposure), was unaffected by freeze/thaw.

• OSTI ID: 276761
• Journal Information: Cement and Concrete Research, Journal Name: Cement and Concrete Research Journal Issue: 6 Vol. 26; ISSN 0008-8846; ISSN CCNRAI
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
CALCIUM OXIDES
CHLORIDES
COMPRESSION STRENGTH
CORROSION PROTECTION
CRACK PROPAGATION
DIFFUSION
ELECTROLYSIS
FREEZING
MECHANICAL STRUCTURES
PERMEABILITY
REINFORCED CONCRETE
REPAIR
STEELS
THAWING