The Client reported significant cracking and concrete spalling on an exposed concrete ceiling of a storage room. It was noticed that the top side of the concrete slab had been cladded over with metal deck roof.
However, multiple penetrations had been made on the roof sheets to make way for pipe and electrical conduit penetrations. A water tank for a centralised air conditioning system was also located on the roof. High humidity and water seepage through the roof slab from roof sheet penetrations expedited the concrete spalling.
Concrete cores were taken from the concrete slab soffit to assess the extent of carbonation and chloride ingress. High carbonation rate and high chloride content were tested from the concrete samples collected.
Temporary props were installed to prevent catastrophic failure to the roof slab when waterproofing works are conducted on the top side and concrete repairs are conducted to the soffit.
SWConsult calculated the number of galvanic anodes required and instructed the contractor to install the galvanic anodes to the repaired area so that they can act as the sacrificial anodes instead of the newly installed reinforcement bars.