Issue No. 2

Abstract

The paper examines the possibility of using the rectified bricks and in particular its installation through the innovative technique of the “thin joint”. The following experimental study was also intended to investigate the possibility of using new mixes by adding different types of plastic fibers, mono and pluri-filament, with the aim of improving the action of sewing inside the joint, to affect the failure mechanisms and provide additional resistance to the combination of clay-adhesive.

Abstract

We report the results of a research addressed to study the mechanical behavior of “terracotta” panels for ventilated facades. The research can be helpful to optimize the size of the panels in order to reduce their fragility.

Abstract

Suitability of using limited additions of three solid waste by-products; homra (H), granulated slag (GS) and fly ash (FA), with Egyptian clay, belonging to Dakhla formation in south western desert, in the conventional red brick batches fired at different temperatures was assessed in comparison with a blank batch. The results showed that as the firing temperature increases, the densification parameters as well as the mechanical properties are improved. Fired brick bodies, containing 10% (FA), exhibit higher densification and mechanical properties at all firing temperatures than those of the other batches. The firing shrinkage was also increased slightly between 750 ° to 800 ° C and sharply from 850 ° to 950 ° C. The XRD and EDAX analyses illustrate that during firing, the main clay constituents of the brick batch react with those of the FA, GS and H additions, forming calcium-rich silicate phases.

Abstract

This study investigates the migration of SO ₄^–2 and Ca⁺² ions in a red-clay ceramic, simulating the process of efflorescence. Ceramic bodies were molded (70x27x9 mm³⁾ by vacuum extrusion formulated with different contents of CaSO₄.2H₂O (0%, 4%, 8%, and 16% in weight) and burnt at different temperatures (800 °C, 850 °C, 900 °C, and 950 °C) for 12 h. Ceramic bodies were characterized in terms of water absorption, apparent porosity and pore size distribution. Efflorescence was evaluated according to the ASTMC67/2003 Standard and by testing the solubilization of SO₄ ^–2 and Ca+2 ions after 1 h with the ceramic bodies immersed in hot water as well as after 7, 14 and 28 consecutive days immersion in cold water. In the quantification of efflorescence, a new image analysis methodology was developed by using the graphic software Image Tools 3.0. The results allowed in establishing a relationship between the efflorescence of the investigated ions, physical properties (water absorption and apparent porosity), pore size distribution and solubilization.

Abstract

The design of bioceramic scaffolds, i.e. artificial structures employed as temporary templates for cell proliferation, is a crucial issue in bone tissue reconstruction and regeneration. An ideal scaffold should be highly porous and bioactive. Additionally, a resistant and permeable surface is required in order to have manageable samples. The production of scaffolds by means of the widely used replication method can lead to samples with weak and brittle surfaces and poor mechanical properties, therefore alternative preparation procedures are necessary. In this work a new protocol to realize bioceramic scaffolds is presented. The obtained samples have an original structure, characterized by an external resistant surface together with a highly porous internal network. The external surface, which behaves as a load-bearing structure for the entire scaffold, guarantees high permeability and manageability. Here the proposed protocol is briefly discussed, together with an overview on the structure of the realized samples. Finally, some preliminary data regarding the scaffolds in-vitro bioactivity are reported.