Document Archives

Corrosion Problems With Lightweight Concrete

• ID:

  938

• ESCSI:

  4350.007

• Author:

  Landgren, Robert and Donald W. Pfeifer

• Publication Name:

  Corrosion Problems with Lightweight Concrete

• Type of Publication:

  Paper

• Publisher:

  Not Given

• Dated:

  1987

• Issue/Volume:

  After 1987

• Other ID:

• Page(s):

  1-25

• Reference List:

  Y

• Abstract:

  The open, porous nature of structural lightweight concrete aggregates can accelerate the corrosion of reinforcing steel embedded in low-to-moderate strength lightweight concrete. The use of a high quality, low water-cement ratio paste in high strength lightweight concrete minimizes, and often negates, the effects of lightweight aggregate porosity in promoting reinforcement corrosion.The primary causes for the accelerated corrosion of reinforcement in lightweight concrete are believed to be:
  1. The comparatively rapid carbonation of chloride-free lightweight aggregate concrete, which causes the paste surrounding the reinforcement to lose its alkalinity and its ability to passivate reinforcing steel against corrosion.
  2. The imbibition of comparatively large volumes of chloride solution by lightweight aggregate concrete. This may accelerate the accretion of chloride in concrete pores to the extent that the threshold chloride content for active corrosion is exceeded.
  3. High porosity produces a tendency for water-saturated lightweight concrete to dry slowly, particularly in massive sections. Slow drying of tile-covered interior lightweight concrete may accentuate the corrosion of top reinforcement in interior slabs containint a chloride-based concrete set accelerator.
  Limited discussions are included of case histories involving carbonation corrosion, corrosion of structures contaminated with deicer salts and corrosion of building interiors involving lightweight aggregate concrete.