Moisture Content Of Concrete Slab

Over time hydrostatic pressure will force that moisture upwards and can cause bubbles in surface treatments and cracks in covering materials that are installed above it.

Moisture content of concrete slab.

Concrete slabs often have thicknesses measured in feet not inches. The second source is moisture rising from below the slab. How moisture gets into concrete. Pieces of concrete are removed by chiseling or stitch drilling and dried in an oven to constant weight.

Internal relative humidity of concrete slab. If an effective low permeance vapor retarder material is not installed directly in contact with the underside of the slab the concrete will be exposed to a perpetual source of moisture rising from below. Testing with either method will tell you how. Moisture meters can only check the moisture near the surface of a concrete slab which is not sufficient for predicting how the slab will react to having sealant applied or other building materials installed over it.

A definitive test that measures the amount of moisture released from the concrete requires a calcium chloride kit or a relative humidity meter. Armstrong recommends conducting a calcium chloride test per astm f 1869 the relative humidity in situ probe test per astm f 2170 or the armstrong 72 hour bond test hygrometer test relative humidity meter placed on floor surface and covered with plastic. What you re looking for is moisture condition that s within manufacturer s specifications to accept the flooring product you are going to apply. Gravimetric this is a direct and accurate method of determining moisture content by weight in the concrete slab.

Most concrete moisture meters only check surface moisture. Moisture tests for concrete slabs. Three methods for testing concrete moisture levels. So you re never going to achieve nor would you want 100 percent dry concrete.

Why concrete moisture is tested. Every slab of concrete has moisture and will always have moisture.