Deterioration of PVC floor covering due alkaline moisture

Concrete as alkaline (pH ∼12,5) and moist material can cause deterioration of polyvinyl chloride (PVC) floor coverings and adhesives through alkaline hydrolysis. Attempts to prevent alkaline hydrolysis have mainly been made by installing PVC floor coverings above ‘dry-enough’ concrete or by using self-levelling low-alkali (pH ∼11…11,5) screeds between concrete and floor coverings. In this study, screed, adhesive and PVC floor covering combinations have been varied by using different floor covering conditions in laboratory test series. VOC emissions have been analysed from flooring material samples (Bulk-VOC). The test samples have been measured for two to three years after installing floor covering. According to the results, a 5 mm layer of low-alkali screed (pH less than 11,5) will effectively protect PVC flooring against alkaline hydrolysis. It could also be concluded that the pH level immediately under floor covering has a better correlation with VOC emission than the RH of concrete in the moment of installing the floor covering.

Use of EMW Radiation in the Building Industry

This paper discusses theory and application of microwave radiation and experimental optimization of microwave radiation to eliminate moisture content in wood elements. Owing to its properties, microwave radiation has been used in the construction industryin modern times, in particular to dry wet masonry of buildings. Effects of electromagnetic radiation on building structures lead to relatively sharp decreases in moisture content from damp building structures or elements. The influence of electromagnetic radiation on building structures lead to oscillation of water molecules contained in the material, which cause a phase transformation of water into vapour. Consequently, the vapour evaporates from the moist material, thereby drying the element exposed to radiation.The article describes experiments carried out at the Faculty of Civil Engineering of the Faculty of Technology in Brno that demonstrate successful decrease of water content in building materials using microwave radiation. First, the understanding of microwave radiationwill be discussed.Following an analysis of research results an optimum intensity of microwave radiation sources as well as the necessary length of the irradiation of microwave radiation have been determined with respect to the particular type of building material and the success rate of elimination of moisture.