Hairline Cracking - Barely visible cracks in random pattern in an exposed concrete surface which do not extend to the full depth or thickness of the concrete, and which are due primarily to drying shrinkage

Hardener - A chemical applied to concrete floors to reduce wearing and dusting

Heavy-Weight Concrete - Concrete in which heavy aggregate is used to increase the density of the concrete; unit weights in the range of 165 to 330 pounds per cubic foot are attained.

Holiday - An area in a diamond ground usually concrete surface that is not ground because the head on the diamond grinding equipment does not cut deep enough to touch a low spot in the surface.

Honeycomb - Concrete that, due to lack of the proper amount of fines or vibration, contains abundant interconnected large voids or cavities; concrete that contains honeycombs was improperly consolidated

Hydration: The reaction of cement with water to form a chemical compound in concrete development.

Hydrophobic .......repels water, ex. Concrete Sealers can make concrete substrates hydrophobic

Hydrolysis ...decomposition of a chemical compound by reaction with water; ex. Sun and abrasion caused a hydrolysis on the concrete surface

Hydrous ... containing water, like a concrete mix design