Test Methods Used in ASTM Specifications for Liquid-Applied Elastomeric Membranes for Waterproofing Concrete

There are two types of waterproofing membranes, each designed to meet the special problems of concrete. The tests required by the two ASTM specifications for membranes—C 836 with a separate wearing course and C 957 with an integral wearing course—reflect the real life requirements of concrete surfaces. Because concrete shrinks when weak, it tends to crack. Both specifications have tests to measure the ability to bridge cracks that open after the floor is laid and coated. Because concrete is very alkaline, both tests require tests of adhesion to concrete after water immersion. These same tests reflect the ability to penetrate and strengthen the powdery surface of the concrete. A major application of waterproofings with an integral wearing course is the decks of parking garages. For this usage, tests of abrasion resistance, water and chemical resistance, and weather resistance are included in ASTM C 957. This paper describes and critiques the rationale for these tests.