Generally, the condition of the exterior concrete in the photo above is unsightly due to the accumulation of efflorescent materials on the surface, excessive staining and discoloration, dark mottling, and "bird bath" flatwork depression. In the region of the spa at this site there is excessive cracking in the spa surround and cantilevered concrete spa coping.
It appears that the excessive efflorescence is the result of a combination of various surface defects in the construction of the flatwork, landscaping improvements, landscape watering, and landscape drainage. Where the deposits of white efflorescence are particularly more prominent, that is where they cover, coat ,and accumulate over larger expanses of concrete.
Efflorescent compounds found on cementitious materials often include one or more of the following mineral forms: anhydrite, gypsum, calcite, dolomite, mirabilite, thenardite, trona, halite, nahcolite, natron, pottash, sylvite, kieserite, glauberite, and a number of other.
All of the above can contribute to the causation of concrete surface defects in the form of efflorescence materials on the concrete flatwork.
If you have what you believe is the appearance of efflorescence on a concrete surface you may want to contact a concrete expert consultant. Please consider contacting Building Forensics International (BFI) for your concrete surface defect consulting needs.
BFI Staff Writer ~