César Medina

Influence of interfacial transition zone on engineering properties of the concrete manufactured with recycled ceramic aggregate

AbstractThe influence of the local micro-properties of the interfacial transition zone (ITZ) on macro-properties on the behaviour concretes is studied for recycled concretes made with 20% and 25% recycled ceramic aggregate from sanitary ware waste. This study carried out using nanoindentation and SEM technique aims to explore interface thickness and variations in its elastic modulus. The results show that the minimum and mean values of the elastic modulus and the ITZ thickness impact concrete mechanical and elastic properties to different degrees. Finally, that nanoindentation provides an indispensable tool for studying and assessing the effect of new materials (e.g. recycled aggregates) on the micromechanical properties of the interfacial transition zone (ITZ) and its effect on engineering properties (compressive and splitting tensile strength and modulus of elasticity) of these new concretes.

Using Ceramic Materials in Ecoefficient Concrete and Precast Concrete Products

The industrial and economic growth witnessed in recent decades has brought with it an increase in the generation of different types of waste (urban, industrial, construction, etc.) despite the waste management policies which have been adopted nationally and internationally. The practice of dumping and/or the inadequate management of waste from the various manufacturing sectors have had a notable impact on the receiving environment, leading to water, soil, air and noise pollution, amongst other complications, and adding to existing environmental problems. At the same time, these practices represent an economic cost. However, if waste is managed correctly it can be converted into a resource which contributes to savings in raw materials, conservation of natural resources and the climate, and promotes sustainable development, all of which complies with strategies for sustainable development within the European Union and Spain. Spain occupies an important position in the ceramics industry world market, second only to China as a producer of wall and floor tiles and, according to data from the Spanish Ministry for Industry, Tourism and Commerce (Subdireccion General de Estudios y Planes de Actuacion, 2009) , the world leader in the ceramic sanitary ware industry. Within the European Union, Spain is the leading manufacturer of ceramics: 26.11 % of all ceramics manufacturing facilities in the European Union are located in Spanish territory (Fraunhofer Institute for Systems and Innovation Research Oko-Institut, November 2009). The Spanish ceramics industry includes the following sectors: ceramic flooring and wall coverings (ceramic floor and wall tiles, respectively), ceramic sanitary ware, bricks and roofing tiles, refractory materials, ceramics for technological applications (insulators, etc.), and ceramic objects for domestic and decorative purposes (tableware and ornaments). This sector has witnessed a fall in production as a direct result of the continuing world economic crisis. Nevertheless, production figures for the main ceramics subsectors in Spain for 2008 were as follows: the brick and roofing tile subsector, 20 million tons (according to data from HISPALYT); the tiles and flooring subsector, 495.2 million m2 (according to ASCER); and the ceramic sanitary ware subsector, 7 million items, providing an indication of the volume of waste involved. The percentage of items rejected for sale and thus discarded depends on the type of industry in question, on product requirements and on