Toward Establishing Recommendations for Silicate-based Surface Impregnation Method for Concrete Structures
By K. Takewaka
Concrete Journal Vol.50, No.10, Oct. 2012
- Synopsis
- In December 2009, the Concrete Committee of the Japan Society of Civil Engineers set up a subcommittee for Study for Silicate-based Surface Impregnation Method for Concrete Structures. With 47 members under chairman Professor Koji Takewaka of Kagoshima University, the subcommittee completed its work in March 2012. Among several surface protection methods, the subcommittee focused its activity on silicate-based penetrants that are able to improve properties of concrete surface layer, to heal cracks and to prevent deteriorations of concrete structures. The main components of silicate-based surface penetrants react with calcium hydroxide which is formed during the process of cement hydration, and form a C-S-H gel in the concrete. The main components used in commercialized penetrants are lithium silicate, sodium silicate, potassium silicate or their mixture. In the actual products, however, it is unusual to find just one of these ingredients; most of the penetrants contain various additives and minor ingredients that aim to stabilize reactivity of main components and to improve their physical properties. However, from an engineering point of view, it is little meaning to categorize silicate-based surface penetrants according to these additives and minor components. The subcommittee, therefore, proposed a classification of surface penetrants into two types that are "Solidifying type" and "Reactive type", according to improvement mechanisms of the main components on concrete surface.
- Keywords:
- surface protection method, silicate-based penetrants, lithium silicate, sodium silicate, potassium silicate, solidifying type, reactive type
