Alessandro LARGO1, Claudio FAILLA2, Marco PREDA2, Francesco SONZOGNI2
The SUS-CON project (funded in the framework of the Call FP7-2011-NMP-ENVENERGY- ICT-EeB) aims at developing new technology routes to integrate waste materials in the production cycle of concrete, for both readymixed and pre-cast applications, resulting in an innovative light-weight, eco-compatible and costeffective construction material, made by allwaste raw materials and characterized by low embodied energy and CO2 and by improved ductility and thermal insulation performances.
The target of low embodied energy and CO2 will be mainly achieved through working on the binders' side, while the target of energy efficiency (heat insulation) will be mainly achieved through working on the aggregates side.
The focus will be on waste materials that, for quantity, distribution and characteristics are also a social problem but, on the other hand, are available in quantities enough for feeding the concrete industry.
For the aggregate production several polymeric waste materials are investigated: waste tyre-rubber, waste electric and electronic equipment (WEEE), waste polyurethane, mixed plastic waste from the scrap of the sorting process of municipal solid wastes.
Regarding the binder systems, their production is based on geopolymer technology which involves the alkaline activation of aluminosilicate raw materials. Several aluminosilicate wastes, commonly found within the EU, such as fly ashes, slags and mineral tailings were investigated as potential source materials for the production of binders.
The project results, while setting-up a novel low cost material for producing energyefficient buildings components, will also contribute to solving the issue of "waste pressure" on towns and to reducing the consumption of not renewable natural raw materials.
Raffaele VINAI1, Ali RAFEET1, Marios SOUTSOS1, Wei SHA1
1 School of Planning, Architecture and Civil Engineering, Queen's University Belfast, BT9 5AG | United Kingdom
Worldwide, building sector calls for the production of 4 billion tonnes of cement annually, consuming more than 40% of global energy. Representing in EU28 about 8.8% of GDP, 29% of industrial employment and with a turnover of 92.5 billion € in 2013, building sector has the potential for absorbing the high volume of slag produced by iron and steel‐making industry. One opportunity is the utilisation of blast furnace slag as binder for concrete. Although already used with Portland cement (PC) in traditional concrete, increasing concerns on CO2 emissions from PC drove the attention towards the development of cementless concrete by alkali activation of aluminosilicate precursors. These materials differ from the PC in terms of mechanical and rheological properties. In this study, a blend of 60% pulverised fuel ash (pfa) and 40% ground granulated blast furnace slag (ggbs) has been used for concrete production. Although a vast literature is available on geopolymer and alkali activated (AA) pastes and mortars, relatively little work is focused on engineering properties of AA concrete. AA concrete has been shown to develop higher compressive strength than the comparable reference concrete, but setting time and workability are more difficult to control as being dependent on several parameters (activators, slag proportion). Moreover, little experience exists on the effects of paste content on strength and workability. The objective of this study was to analyse the effects of binder content, paste content and water to solid ratio on mechanical and rheological properties of the concrete.
Visser, J.H.M., Bigaj-van Vliet, A. J.
Department of Structural Reliability, TNO, Postbox 49, 2600 AA Delft, The Netherlands
In order not to hamper innovations, the Dutch National Building Regulations (NBR) allow an alternative approval route for new building materials. It is based on the principles of equivalent mperformance which states that if the solution proposed can be proven to have the same level of safety, protection of health, energy efficiency and protection of the environment, it is accepted as well.
The framework of equivalence performance has been worked out in this paper with respect to safety. Three types of assessment criteria have been derived: for individual vales, for characteristic values and for relationships. More than one assessment criteria can apply at the same time. An example for a new material containing 50 % of recycled concrete and 50 % of recycled sand-lime brick aggregates illustrates the consequence of the assessment for two properties: compressive strength and tensile strength.
The assessment procedure provides a new route for fast incorporation of new concrete-like materials in construction without compromising the safety of the structures. This will not only stimulate innovations. Since it is expected to be applicable for many newly developed green materials, it also makes a significant contribution to reduction in CO2 and energy consumption as well as raw materials in a relatively short time.
Study on the suitability of volcanic amorphous aluminosilicate rocks (perlite) for the synthesis of geopolymer- based concrete.
M. Taxiarchou, D. Panias, Ch. Panagiotopoulou, A. Karalis, C. Dedeloudis
Geopolymerisation is a low cost, low energy demanding, green technology that can transform a variety of silicate and aluminosilicate raw materials and industrial by- products to useful, high added value products. Due to their excellent mechanical properties, the application of geopolymeric materials for the replacement of traditional construction materials is gaining ground. The most commonly used raw materials for geopolymer synthesis include metakaolin, fly ash, Ground Granulated Blast Furnace Slag (GGBFS) and their mixtures. In this work, an amorphous aluminosilicate rock (perlite) was selected as raw material, in order to determine its ability to synthesize new Portland cementless binders for concrete. The effect of the following synthesis parameters on the development of the mechanical properties of the geopolymeric formulations were studied:
• The curing conditions (t 24, 48, 72h , T 50, 70, 90 °C)
• The water/ solid mass ratio ( mw/ms 0.28-0.37)
• Si/Al molar ratio= 5.6-6.5
• The alkali content and type of alkali ion (R/Al molar ratio 0.65-1.05 R: Na or K)
The structural changes were identified by means of XRD, FTIR and SEM while the mechanical properties were evaluated through compressive strength measurements. The most promising formulations were used for the synthesis of mortars using standard silica sand, according to ASTM C109/109C. Also in this case, compressive strength measurements were carried out, while the structure was observed with XRD, FTIR and SEM. The present study showed that perlite is a promising raw material for geopolymer synthesis resulting in geopolymeric pastes with compressive strength higher than 30 MPa. In contrast to the other raw materials currently used for geopolymerisation, the geopolymerisation of perlite requires prolonged curing time of a total duration of 5 days at 70 °C.