Formwork, Concrete Polymer Modified Mortar Layer Of Protection Performance

In this paper the properties of the polymer modified cement mortar are studied of DIDY formwork concrete surface coated layer for protection. The emphasis is focused on the permeability and cracking-proof feature. Use the principle of material complex, carboxylic styrene-butadiene rubber latex added to the ordinary mortar forms PMM which takes the place of the conventional mortar as the surface coated. It can improve the cracking-proof feature, permeability, flexibility, as well as the compatibility with formwork concrete, to protect the formwork from corrosion and finally to enhance the durability of formwork concrete.In the aspect of improving the cracking feature, compatibility and flexibility, the author has done experiments, including strength, modulus of elasticity experiments, and design some experiments similar to the practical structure and circumstance including adhesion strength between fresh mortars and old ones, between mortar and polystyrene board, mortar shrinkage in concrete circle, mortar shrinkage at different strength and different polymer-cement ratio, and temperature deformability at different strength and different polymer-cement ratio on mortars, on different type of formwork and on mortars with different type of formwork.In the aspect of mortar permeability the author has done some experiments, including the water absorption, porosity, weatherability, anti-freeze-thaw cycle, carbonation and the chloride diffusion experiment, and compared those properties with conventional mortar to testify the modified effects.On the base of these experiments, the method of SEM was used to analyze the microstructure and hydration mechanism of polymer modified cement mortar, and the author draws a conclusion that the 9 percent of polymer-cement ratio is the optimum ratio. Finally, make allowance for economic factors, the mixture technique and engineering cost are discussed. The PMM can be gained better properties at a low polymer-cement ratio, which have a great economic significance to enlarge its engineering application.