METHOD TO IMPROVE THE EFFICIENCY OF VOLUMETRIC HYDROPHOBISATION OF PROTECTIVE LAYERS OF BUILDING STRUCTURES

Introduction. The protection and repair of concrete structures are the challenges of high priority, some solutions of which are presented in standards such as EN 1504 and GOST 32016–2012. Application of waterproof compounds is one of the main methods to protect concrete structures from water impact. Sealants are widely used to preserve the concrete properties, providing surface or volumetric hydrophobization. Purpose of the study was to develop and substantiate a new method to improve the efficiency of volumetric hydrophobization of protective layers made of dry mix mortar (DMM) based on microcement. Materials and Methods. Microcement MC MicroOST brand produced by New Technologies LLC was used as the main component of dry mixes, aluminous (AC-35-40) and high aluminous (HAC-70) cements were considered as aluminate components. Comparative assessment of hydrophobic properties of the prepared formulations of DMM based on microcement was carried out by contact angle and water absorption indicators. Results of the study showed that samples with introduction of aluminate component, such as high alumina cement (HAC), demonstrated high level of hydrophobicity and faster completion of water uptake into the material, relative to samples with HAC-35-40, samples of control formulation K-1, or with alternative additives (formulation with Mapelastic). It was found that introduction of high alumina cement in amount of 10–15 % provides maximum hydrophobicity for the proposed method. Analysis of the form of the water contact angle revealed formation of water-repellent film on the treated surface of samples with 10 and 15 % of high alumina cement. With regard to other coatings, it has been noted that they are highly resistant to water penetration deep into the material. These results demonstrate high efficiency of the proposed method to improve volumetric hydrophobization of protective layers