Effect of tiles, bricks and ceramic sanitary-ware recycled aggregates on structural concrete properties

In this paper, tile ceramic waste (TCW)1, red clay bricks (RCB) and ceramic sanitaryware (CSW) were used as the partial replacement (14-30 wt.%) of natural limestone aggregates to produce structural concrete. The natural and recycled aggregates were characterised, and the strength and density of the hardened concrete were investigated after 7 and 28 curing days at room temperature. The TCW concrete obtained the best compressive strength results (strength gain of up to 7% with 20 wt.% waste after 28 curing days). The mechanical properties of the CSW recycled concrete were similar to those of traditional samples, and slightly diminished with curing time and aggregate substitution, with a maximum strength loss of 5.77% for the 30 wt.% replacement. Although the RCB concrete presented the greatest strength loss (up to 18.4% after 7 curing days), it exhibited the best improvement of the strength with curing time, which resulted in a strength loss of only 11% in the 30 wt.% RCB concretes cured for 28 days. These results demonstrate the feasibility of using TCW and CSW as recycled aggregates in structural concrete production without significantly affecting the developed recycled concrete’s compressive strength

Contribution of Roof Refurbishment to Urban Sustainability

Achieving sustainable urban environments is a challenging goal—especially in existing cities with high percentages of old and obsolete buildings. This work analyzes the contribution of roof refurbishment to sustainability, considering that most roofs are currently underused. Many potential benefits of refurbishment can be achieved, such as the improvement of the energy performance of the buildings and the use of a wasted space for increasing green areas or for social purposes. In order to estimate the degree of the improvement, a vulnerable area in Castellón (east Spain) was selected as a case study. A thorough analysis of the residential building stock was undertaken. Using georeferenced information from the Cadastral Office we classified them according to typology, year of construction and roof type. Some refurbishment solutions were proposed and their applicability to the actual buildings was analyzed under different criteria. The theoretical benefits obtained in the neighborhood such as energy and carbon emissions savings were evaluated, together with the increase of green areas. Moreover, other social uses were suggested for neglected urban spaces in the area. Finally, a more accurate analysis was performed combining different solutions in a specific building, according to its particular characteristics

Stiffness variation of porous titanium developed using space holder method

The excellent properties of Ti have resulted in its generalised use for bone implants. However, Ti is very stiff in comparison with human cortical bone, and this creates problems of bone weakening and loosening of the implant. This article discusses the mechanical properties (flexural and compressive strength, and stiffness) of porous Ti-6Al-4V specimens developed using the space holder method. These properties are examined relative to the production process parameters: compacting pressure and sintering time, as well as temperature, and the addition of spacer and its particle size. It is seen that when spacer is added, compressive strength decreases with the application of compacting pressure and that these are the most influential parameters. The developed pieces show a closed and unconnected porosity. Small additions of spacer (25 vol.-%) reduce stiffness to around half of that shown by the solid material, and the resulting pieces are strong enough to be used as bone substitute. © 2011 Institute of Materials, Minerals and Mining.The authors wish to thank the Spanish Ministry of Science and Innovation for the support received under project no. PET2008_0158_02. The translation of this article was funded by the Universidad Politecnica de Valencia.Reig Cerdá, L.; Amigó Borrás, V.; Busquets Mataix, DJ.; Calero, JA. (2011). Stiffness variation of porous titanium developed using space holder method. Powder Metallurgy. 54(3):389-392. https://doi.org/10.1179/003258910X12707304455068S389392543RYAN, G., PANDIT, A., & APATSIDIS, D. (2006). Fabrication methods of porous metals for use in orthopaedic applications. Biomaterials, 27(13), 2651-2670. doi:10.1016/j.biomaterials.2005.12.002in ‘ASM handbook’, Vol. 2, ‘Properties and selection: nonferrous alloys and special-purpose materials’, 1170; 1990, Materials Park, OH, ASM International.Asaoka, K., & Kon, M. (2003). Sintered Porous Titanium and Titanium Alloys as Advanced Biomaterials. Materials Science Forum, 426-432, 3079-3084. doi:10.4028/www.scientific.net/msf.426-432.3079Niinomi, M. (2008). Mechanical biocompatibilities of titanium alloys for biomedical applications. Journal of the Mechanical Behavior of Biomedical Materials, 1(1), 30-42. doi:10.1016/j.jmbbm.2007.07.001Rack, H. J., & Qazi, J. I. (2006). Titanium alloys for biomedical applications. Materials Science and Engineering: C, 26(8), 1269-1277. doi:10.1016/j.msec.2005.08.032Köhl M, Bram M, Buckremer HP, Stöver D: Proc. Conf. Euro PM2007, Toulouse, France, October 2007, European Powder Metallurgy Association, 129–134.Bram M, Bogdanski SH, Koller M, Buchkremer HP, Stover D: Proc. Conf. Euro PM2005, Prague, Czech Republic, October 2005, European Powder Metallurgy Association, 517–522.Reig L, Amigó V, Busquets D, Salvador MD, Calero JA: Proc. Conf. Sintering 2008, La Jolla, CA, USA, November 2008, American Ceramic Society. 273–282.Degischer, H., & Kriszt, B. (Eds.). (2002). Handbook of Cellular Metals. doi:10.1002/3527600558Comín M, Peris JL, Prat JM, Decoz JR, Vera PM, JV: Hoyos: ‘Biomecánica de la fractura ósea y técnicas de reparación’, 66–69; 1999, Valencia, Publicaciones UPV.Gibson LJ, Ashby MF: ‘Cellular solids: structure and properties’, 175–231; 1999, Cambridge, Cambridge University Press.Making metal foams. (2000). Metal Foams, 6-23. doi:10.1016/b978-075067219-1/50004-0Esen, Z., & Bor, Ş. (2007). Processing of titanium foams using magnesium spacer particles. Scripta Materialia, 56(5), 341-344. doi:10.1016/j.scriptamat.2006.11.010Leyens, C., & Peters, M. (Eds.). (2003). Titanium and Titanium Alloys. doi:10.1002/3527602119Lütjering G, Williams JC: ‘Titanium’, 2nd edn, 13–51; 2007, Berlin, Springer, Engineering Materials and Processes

Use of residual diatomaceous earth as a silica source in geopolymer production

The use of binders as an alternative to Portland cement has gained importance in recent years. Among them, geopolymeric binders, developed by the reaction between an aluminosilicate precursor and a high alkalinity solution, have become one of the most promising alternatives. The activating solution generally comprises waterglass and sodium hydroxide. Since waterglass is the most expensive material and has a high environmental impact, using alternative silica sources will lead to more sustainable binders. Previous studies have successfully used rice husk ash (RHA) as a silica source. This research aims to assess the possibility of using diatomaceous earth (or diatomite) as an alternative silica source, like the previous studies with RHA. Diatomite is a sedimentary rock with a high amorphous silica content formed by fossilized diatom remains. In this work, the geopolymer was obtained using a fluid cracking catalyst residue as the precursor and six different activating solution types prepared with commercial products, residual diatomite (from beer and wine industries) and RHA. The results open a new possible route for the reuse and recovery of diatomaceous earth residue, although the compressive strength results of the mortars were slightly lower than those for mortars prepared with RHA or commercial reagents

Reutilisation of hazardous spent fluorescent lamps glass waste as supplementary cementitious material

Spent fluorescent lamps glass (SFLG) waste, manually and mechanically processed in a lamps waste treatment plant, was used to partially replace up to 50 wt% Portland cement (PC). Both waste types exhibited similar pozzolanic activity. The mortars containing up to 35 wt% SFLG met the specifications for other pozzolanic materials (e.g. fly ash) and, after 90 curing days, their compressive strength values were similar to or higher than those of the 100% PC sample (58.8 MPa). Our results provide an alternative reutilization process for this hazardous waste to reuse SFLG as-received (no washing to reduce mercury) and contributes to less PC use.Funding for open access charge: CRUE-Universitat Jaume

Categorization and Quantification of Construction Waste of Commercial Buildings in Iraq

The construction sector has a significant and direct relationship with the development and growth of countries. Meanwhile, the population growth and the massive expansion of buildings and infrastructure projects keep up with living standards, generating more construction waste. Knowing the categorization for the CDW is very important to get better information about the waste and to have a proper plan to manage these wastes during the construction process. This study aims to categorize and quantify the CDW produced during the construction of a commercial building in Iraq, with a total floor area of 900 m2 (A three-story building with 300 m2 for each story). Data acquisition for this study took approximately two years. It concludes that soil waste represents 86.75% of total waste produced during the construction of the building, with the remaining 13.25 % mainly composed of brick (47.03%), followed by concrete (19.27%), mortar (10.65%), ceramics and marble (6.68%), gypsum (4.88%), steel (3.08%), wood (2.37%), and subbase (2.02%)

Compressive strength and microstructure of alkali-activated blast furnace slag/sewage sludge ash (GGBS/SSA) blends cured at room temperature

In the present work, ground granulated blast furnace slag (GGBS) and sewage sludge ash (SSA) blends were assessed for the production of alkali-activated pastes and mortars. Percentages of SSA to substitute GGBS ranged from 0–30 wt.% and sodium concentrations of 6–10 mol.kg-1 were used for the activating solutions. Pastes and mortars were cured at 20 ºC for up to 90 days. Raw materials were characterised by granulometric analysis, XRF, XRD, FTIR and SEM techniques. The replacement percentage of GGBS by SSA and the sodium hydroxide concentration of the alkaline activator were optimised to produce mortar with compressive strengths close to 30 MPa after 28 curing days at room temperature. Best results were obtained in samples blended with 20 wt.% SSA activated with 6 mol.kg-1 NaOH solutions which, according to the XRD, FTIR and microscopic results, contained higher amounts of (N,C)-A-S-H gel. The potential use of SSA for the development of alternative cementitious materials at room temperature has been demonstrated

Utilisation of Ceramic Stoneware Tile Waste as Recycled Aggregate in Concrete

The construction industry has a significant environmental impact and concrete production is responsible for a large part of CO2 emissions and energy consumption. This study focused on the reutilisation of a specific type of tiles ceramic waste (TCW), composed only of stoneware and porcelain stoneware tiles, hereafter referred to as ceramic stoneware (CS), as recycled aggregate in concrete. Natural limestone and CS aggregates (sand and gravel) were characterised (particle size distribution, water absorption, resistance to wear, density and X-ray diffraction analyses) and recycled aggregate concrete (RAC) was prepared by replacing 20, 50 and 100 vol.% of sand and gravel, separately. Concrete workability generally improved with CW addition, especially when replacing natural gravel. Although the compressive strengths of the concrete specimens prepared with recycled sand were slightly lower than those of the reference specimens, similar or better results were recorded with the recycled CS gravel. In consonance, the RAC developed with recycled gravel obtained lower water penetration depths than the reference concrete. No significant variation in tensile strength was observed when varying CS content (values within the 2.33–2.65 MPa range). The study contributes to sustainable construction practices and circular economy by promoting the valorisation and reutilisation of industrial waste and reducing the consumption of natural resources.This research was funded by Generalitat Valenciana, the regional government of Valencia, through Project INVEST/2022/243, and by Universitat Jaume I (UJI) through Project UJI-B2021-34

Prevención en trabajos de acceso y posicionamiento mediante cuerdas

Pese a que, debe priorizarse la aplicación de medidas destinadas a eliminar los riesgos en su origen (RD 2177/2004), existen determinadas situaciones en obra, como la colocación de redes de seguridad, la realización de determinados trabajos en cubierta... en las que no se puede eliminar el riesgo, ni mantener al trabajador alejado. En estos casos, la aplicación de medidas de protección colectiva resulta también insuficiente, por lo que debemos recurrir al uso de equipos de protección individual que nos ayuden, bien a prevenir el accidente, bien a proteger al trabajador en el caso de que ocurra. El objetivo de las prácticas de Seguridad y Salud realizadas en la Universitat Jaume I, es conocer y saber aplicar correctamente técnicas de acceso y posicionamiento mediante cuerdas.Consejo General de la Arquitectura Técnica de Españ