Water-Soluble Chloride in Mortar and Concrete

Water-soluble chloride, if present in sufficient amount, is capable of initiating or accelerating the corrosion of some metallic materials embedded in or contacting cementitious mixtures such as mortar and concrete. Chloride content, along with other factors, can be indicators for the possibility of corrosion of embedded metallic materials. This test method is used to determine the water-soluble chloride content in cementitious mixtures, either in new construction or existing structures. (Note: Water-soluble chloride content can vary with time. For example, water-soluble chloride content could increase due to additional chloride ingress. Alternatively, water-soluble chloride content could decrease due to chloride-binding or leaching.) Test conditions are capable of affecting water-soluble chloride determinations. Take caution when comparing results from this test method with those from other test methods. Sulfides are known to interfere with the determination of chloride content. Blast-furnace slag aggregates and cements contain sulfide sulfur in concentrations that are capable of such interference and produce erroneously high test results. Treatment with hydrogen peroxide is used to eliminate such interference. There are aggregates that contain chloride that is not available for corrosion. Such chloride will be detected by use of this test method.