concrete cover

 Environ-mentExposure ConditionsMinimum  N/mm2
   20253035404550
 MildConcrete surfaces protected against weather or aggressive conditions3025202020**20**20**
Nom-
inal
cover
(mm)
Mode-
rate
Concrete surface away from severe    rain
Concrete subject to condensation
Concrete surfaces continuously under water
Concrete in contact with nonaggre-ssive soil
40  353025202020
 SevereConcrete surfaces exposed to severe rain, alternate wetting and drying or severe condensation 454030252520
 Very
severe
Concrete surfaces exposed to sea water spray, corrosive fumes  5040303025
 ExtremeConcrete surfaces exposed to abrasive action, e.g. sea water carrying solids or flowing water with pH  ≤ 4.5 or machinery or vehicles   60504030
Maximum water/cement ratio0.650.650.600.550.500.450.42
Minimum cement content, (kg/m3)315325350375400410420
*       This table relates to aggregate of 20 mm nominal maximum size.
**     May be reduced to 15 mm provided the nominal maximum aggregate size does not exceed 15 mm.

ট্যাগ