QUARRY AND AGGREGATES
The aggregates sector and the C&D Wastes management, an historic opportunity?
From the Business Committee on Recycled Aggregates and Construction and Demolition Waste Management of ANEFA, the aim is to develop the line of activity for the production of Recycled aggregates and management of C&D Wastes in the companies of the aggregate sector, such as a part of the strategy of business diversification, based on the opportunities and synergies that this activity may represent for the companies already producing natural aggregates.
The article develops sectoral actions to promote the integration of the production of recycled aggregates and the management of C&D Wastes in the aggregates sector, as well as the strategic initiative to integrate recycling in the aggregate industry. In addition to the strengths of the sector, the main barriers for this activity are analised, among which the aggregates sector does not feel it as an activity of its own, the difficulty of managing permits, technical adaptation of treatment facilities, the complexity of waste legislation, other barriers such as public concessions of C&D Wastes management plants, the political pressure from a part of the recycling sector and the fact that the current market for recycling is almost non-existent in Spain.
Hardness of moulds used in the standard cement mortar test method
The European standard EN 196-1:2005 “Methods of testing cement — Part 1: Determination of strength” has been prepared by Technical Committee CEN/TC 51, ‘Cement and building limes’, the Secretariat of which is held by IBN. This European standardsupersedes EN 196-1:1994, which is withdrawn. In this edition, the testing procedure has been revised with respect to hardness and surface texture of moulds. This paper gives technical information with regard to hardness of moulds in order to be send to the CEN/TC 51/WG 15.
Measurement of the Rheology with Schleibinger
The ever-growing demands on the properties of mortar and concrete are closely linked to the permanent further development of these cement-based mixtures. The research of these materials can be divided into three fi elds of investigation which are durability, dimension stability and workability. While durability and dimension stability focused on hardening processes, the workability deals with the liquid or plastic state of cementitious materials. The material properties such as hardness, strength and durability can be only achieved following a period of plasticity. Hence, the adjustment of the workability settings and the control of them play an essential role for the further properties of the materials. In this article we present different models of rheometers adapted to the different materials in cement based on their particle sizes.
Accelerated concrete prism method for evaluating the alkali-silica reactivity
Since 2007, the authors have been working on implementing the accelerated concrete prism method (IRAM 1700) for evaluating the alkali-silica reactivity of different types of concrete aggregates from Argentina. This paper presents the results obtained with this test method, applied on a greater number of aggregate samples, with the aim of evaluating the reliability of the expansion limits proposed. It is concluded that the accelerated concrete prism method is a good screening test for ASR.
Standard model for Environmental Risks Report (MIRAT) for gravel activities
Following the publication of the Royal Decree 2090/2008 of 22 December, which approved the regulation of partial development of Law 26/2007 of 23 October on Environmental Liability, the Federación de Áridos (Spanish Aggregates Federation) decided to develop a Model for Standard Environmental Risks Report (known by its Spanish acronym MIRAT) that would enable operators of gravel pits to have a practical tool to perform an environmental risk assessment in order to take the necessary measures to prevent environmental damage or to take the necessary restorative measures in the case it had occurred. This article summarizes the MIRAT developed for gravel activities and its computing tool ‘ARACEA’.
Structural tipologies in the Caixa Forum building in Zaragoza
Caixa Forum Building in Zaragoza, designed by Carme Pinós, is a cultural centre with exhibition and multipurpose halls, classrooms and an auditorium. The building comprises of two cubic volumes that merge in a vertical communication core. Each of the buckets is partially cantilevered, thanks to a network of large edge trusses. The remarkable architectural design has adopted a variety of structural steel, concrete and mixed solutions, which are analyzed in this article. The vertical support system consists of a series of concrete walls with lightening holes, and a large composite steel-concrete column fusiform shaped. On the other hand, the horizontal support system consists of a concrete solid and lightened slabs and, steel decking slabs supported on large metal trusses. The entire building is wrapped by a only roof–façade system, which is backlit by the façade faces. The variety of structural elements required different kinds of concrete, special formwork systems, and diverse connection systems.
All this required a detailed study of the necessary features of each element, analysis of the auxiliary resources and consequently, a detailed planning that took into account the above aspects. The composite steel-concrete column fusiform shaped, needed a special reinforced steel formwork in order to resist the high pressure of the self compacted concrete. The connection of the steel trusses to the concrete walls transmitted a considerable load so it was mainly solved by imbibing the steel structure in the concrete. In the case of the horizontal resistant structure, each typology responds to a different requirement: lightness in cantilever areas, stabilizing weight in the central core and sound insulation in the auditorium cover.