The Research Of Cementitious Capillary Cristaline Waterproofign Coatings

Cementitious capillary crystalline waterproofing coating(CCWC), characterized by its permanent waterproofing effect, self-rehabilitating ability, good aging resistance and corrosion resistance, is a new type of cement-based waterproofing material which reactive ingredient can permeate into the internal part of concrete structures through capillary pores or cracks and react with cement hydrates and anhydrates.On the basis of the comprehensive study and analysis of the literatures concerning the mechanism and properties of CCWC, the substances that can react with anhydrate or hydration products and other supplementary ingredients were selected, and variety of experiments were conducted by means of cross experimental design. The effects of chemical composition and dosage of raw materials, curing condition, and chemical admixtures on waterproofing ability were tested and analyzed. A optimum formulation of cementitious capillary crystalline waterproofing coating(named as GT waterproofing coating) was successfully developed, based on silicate cement., The performances of GT waterproofing coating were examined in accordance with GB18445?001, and the results were compared with those of two types of widely used waterproofing coatings Xi and Xi. Test results showed that the properties such as impermeability, strength, self-rehabilitating ability and corrosion resistance are superior to those of the counterparts.Stereomicroscope, SEM, and XRD analysis were employed to investigate the mechanism of waterproofing and the improved microstructure of concrete structures. Positive results were obtained for the occurrence of the permeation and crystallization processes.The study indicates that GT coating has the following advantages:a. The waterproofing effect is remarkable. Brushed with the thickness of 1.0-1.2 mm, it can improve the impermeability pressure up to 3 times that of blank samples;b. The crystalline reaction can continuously carry out, sealing the crack and waterproofing for ever if water is existent;c. It has very strong capillary ability in pores or cracks that it can penetrate into 50mm depth in 28 days;d. Very good environmental adaptability, and can be used as normal at PH 3.0-12.0;In addition, GT coating is inorganic rigid material, and it can be easily fabricated and applied, suit to complicated and bulk concrete structure surfaces. Therefore it has a bright market prospect in the field of underground structures, water conservative engineering, bridges, ponds and water disposal plant, etc.