Effect of Injecting Epoxy Resin Adhesive into Cement Mortar on Tile Adhesion Performance

Large porcelain tiles have attracted increased demand owing to their cost-effectiveness and superior esthetics. Here, an epoxy resin adhesive was injected into cement mortar, which was then applied to tiles. The adhesion performance of the tiles was subsequently evaluated in terms of the permeability and drying shrinkage under various curing conditions. The epoxy resin adhesive not only penetrated the tile–mortar and mortar–concrete interfaces, but also directly penetrated the mortar, thus enhancing the mechanical adhesion at each interface. In addition to the mechanical adhesion between the tiles and mortar, the epoxy resin adhesive prevents the degradation of adhesion due to shear stress by minimizing the moisture evaporation and shrinkage of the mortar. Evaluation of the adhesion characteristics under water and freeze–thaw curing conditions revealed the vulnerability of the epoxy resin to moisture; however, adequate adhesion performance was observed when the epoxy resin was air-cured prior to being exposed to harsh environments. Moreover, the injection method did not prolong the construction period, but could potentially reduce it during actual application. Nevertheless, further research on the adhesion performance of tiles with injected epoxy resin adhesive is required to evaluate the long-term durability.

Development of Scheelite Tailings-Based Ceramic Formulations with the Potential to Manufacture Porcelain Tiles, Semi-Stoneware and Stoneware

New ceramic formulations based on scheelite tailing were developed, and their potential in the ceramic industry was evaluated. Green bodies with different contents of scheelite tailing (0–8 wt%) were sintered (1150 °C, 1200 °C, and 1250 °C) and characterized in terms of the main mineralogical phases, microstructure, and physico-mechanical properties. The mullite was the main phase identified in all sintered temperatures. This result was also ratified with the aid of scanning electron microscope (SEM) images, in which small needles of the mullite were detected. The presence of mullite is required because it contributes to increasing the mechanical resistance of the material. The physico-mechanical properties measured (water absorption, linear shrinkage, apparent porosity, and flexural strength) were compared to the ISO 13006, and the samples sintered at 1150 °C presented potential to be used as semi-stoneware, while those sintered at 1200 °C and 1250 °C can be employed stoneware and porcelain tiles, respectively.

Rheological and Fired Properties of Malaysia Clay from Ipoh (Perak) and its Application in Ceramic Tiles

Clay is an important raw material in manufacturing of ceramic products especially ceramic tiles. Local clays are important for demand of local ceramic tile industries especially the advantages in terms of transportation cost. The research work is aimed to provide scientific data on rheological behavior and fired properties of Ipoh clay from Perak, Malaysia and its application in ceramic tiles. The studied clay was characterized by mineralogical analysis and chemical composition to determine the mineralogy of Ipoh clay. Rheological behavior was identified by deflocculant demand, thixotropy and zeta potential. Fired properties were determined by linear fired shrinkage, water absorption, bulk density, apparent porosity and fired colour. The Ipoh clay is considered suitable to be used for wet milling process in manufacturing of ceramic tiles due to highly negatively charge from the outcome of zeta potential. Ipoh clay is considered as dimensional stable with range of linear fired shrinkage of 2.5 to 3.5% from firing temperature from 1000 – 1050 °C. Firing temperature of 1050 °C – 1250 °C shows drastic increase in linear fired shrinkage from about 3.5% to above 10% together with drastic reduction in water absorption from about 19% to 5%. Ipoh clay is considered not suitable to be used in high amount for application in porcelain tiles that need water absorption of almost zero together with low in apparent porosity. However, Ipoh clay has good fired colour, which is suitable for technical polished porcelain tiles.

REFRACTORY CLAY RAW MATERIALS OF REPUBLIC OF BELARUS FOR PRODUCTION OF THE PORCELAIN TILE

The possibility of replacing imported refractory clays and kaolines, which are part of porcelain stoneware mix, with refractory clay materials of the Republic of Belarus, in particular quartz-pyrophyllite-kaolinite rock and kaolin of “Dedovka” and “Sitnitsa” deposits, was explored. Porcelainised stoneware body formulations of JSC “Keramin” (Minsk, Republic of Belarus) was taken as the basis. It was found that physico-chemical properties and operational characteristics of porcelain tiles comply with the requirements of EN 14411: 2014, when adding 2.5–15.0 wt.% quartz-pyrophyllite-kaolinite rock. Incorporation of quartz-pyrophyllite-kaolinite rock in percentage higher than 15.0 wt.% resulted in reduction in the total amount of the vitreous phase of porcelain stoneware, thus increasing water absorption, apparent porosity as well as reduces flexural strength and bulk density. The main crystalline phases in the synthesized materials were quartz and mullite. It was also revealed that imported kaolines could be completely replaced by kaolines of “Dedovka” and “Sitnitsa” deposits. In this, required physico-chemical properties and operational characteristics of porcelain tiles was maintained. SEM analysis revealed that specimens synthesized using considered kaolines show quite dense microstructures, with a high degree of vitrification. The gas phase in these materials was practically absent, the presence of only individual small irregular pores was found. XRD analysis indicated that the major phases were mullite, quartz, microcline and hematite. It was hematite that gives the obtained porcelain stoneware samples a dark gray color scheme. Thus, the use of domestic refractory clay raw materials provides import substitution and declining production costs.

Estimating the reduction of the firing temperature produced by the addition of energetic fluxes in porcelain tiles through the Fluegel’s model

Reducing the firing temperature and accelerating the densification process bring economic and environmental benefits. This study used Fluegel’s viscosity model, developed for glasses, to estimate the decrease of the firing temperature produced by the introduction of energetic fluxes in a porcelain body. The experimental results confirmed the prediction of the model, a 30 ºC reduction in the temperature, for the addition of wollastonite. However, for the addition of spodumene, the reduction was slightly higher than the predicted. These results suggested that Fluegel’s model may be used to estimate the effects of the introduction of energetic fluxes in porcelain tile compositions. However, the predictions should be seen as a general orientation. Among the limitations of the model were the extrapolation of limit values established by the model for the composition and, above all, the initial hypothesis that the chemical composition of the vitreous phase in porcelain tiles is constant.