Rod wrote:Concrete is supposed to stop further rust but not always the case - shown by spalled concrete especially on exposed surfaces especially where insufficient cover has been created during construction.
To resist moisture, air entrained concrete is specified and highway structures are often sprayed with a special sealer after formwork is stripped to prevent salt action.
Rod
A number of council housing was built in Romsey after the 2nd WW using Reema PRC (prefabricated reinforced concrete). These were sold off in the 80s(?) to the tenants on very preferential terms under the govt policy of the day. However those who tried then to sell them to release the equity were found to be un mortgageable due to what the press called concrete cancer -cracks caused by the swelling of rusting re-bar in the precast panels.
A vast local expense the council offered to buy these back at full market price assuming no concrete cancer and those they still owned plus those that were bought back, had a brick outer skin built round them onto new foundations where unusually the outer skin was structural and the roof modified to also bear on the brick.
The roads with these houses in now look rather peculiar with a mix of slightly larger brick houses interleaved with a few painted concrete ones still in private hands that possibly can never be sold other than to cash buyers.
Bob