Determination of cement components
This paper presents the experimental procedures of the Spanish standard UNE 80216:2010 and the European Technical CEN Report CEN/TR 196-4:2007 regarding the quantitative determination of cement components. Basic principles, field of application and limits of the experimental procedures are also studied. Such methods are based on the chemical selective dissolution because of its ease, rate and precision.
Contribution of blended cement in sustainable concrete production. Part II
Due to future requirements and commitment to contributing to sustainable development, increasingly demanding requirements for more durable concrete and concrete structures are set, with an ultimate goal of reducing consumption of natural resources in the course of production, construction, maintenance and use.
The described set of tests was designed to research impact of blended cements on properties of concrete through: durability of concrete; environmental and sustainability effects of production of concrete using blended cements, especially reduction of consumption of natural resources and reduction of CO2 emission.
The research placed an emphasis on durability of the concrete and impact the cement makes on durability. The tests have been conducted using three types of concrete. The first type of concrete was made using reference cement, which was pure portland cement. The second type of concrete was made using blended cement consisting of 65% the reference concrete, 20% slag admixture, 10% fly ash admixture and 5% limestone admixture. The third type of concrete was made using blended cement consisting of 50% the reference concrete, 20% slag admixture, 20% fly ash admixture and 10% limestone admixture, as described in the part I of the paper. Results of the research described in this paper indicate possibility of increasing durability of the concrete in respect of greater resistance to penetration of fluids through use of blended cements.
New Novaflam burner for cement rotary kilns
Fives-Pillard has developed its new Novaflam® burner for cement rotary kilns, based on its wide experience on this field. The principal advances with regard to previous burners are: the increase of the rate of alternative fuels, which allows a cost reduction, and makes it is a more ecological equipment; close to the higher simplicity of managing and maintenance, which makes it an ideal burner for the workmen of the factories. The experiences with this new burner have confirmed the achievement of the set goals: improvements in the production and quality of the clínker, reduction of exploitation costs and emissions, simplifi cation in working and maintenance, without detriment for the possibilities of adjustments, etc.
EQUIPMENT PROVIDERS 2
Fast-heating concretes Kilofast®
Beginning with the necessity raised on the part of the cement sector dealing with the usage of refractory concrete that would allow rapid heating without it involving cracking the refractory coating, our Department of Investigation, Development, and Technological Innovation has developed a range of products that, conserving the mechanical characteristics for compression and abrasion resistance, and the properties that protect against chemical attacks, of our low cement-content concrete, would allow a more rapid heating process.
The foundation in obtaining our Fast-heating concrete Kilofast®, was the usage of raw materials of the highest-quality that possess highly-reactive nano-sized particles, that make the elimination of any type of bonding agent used until now possible, and thus the elimination of any water-constituted molecules from the concrete structure, which cause cracks in the concrete, and on a macro-scale the “spalling” of the coating when using a rapid heating process.
In our line of Kilofast® concretes, we have achieved a high-viscosity structure, and thus concretes whose permeability at low temperatures is superior to those of other lines of refractory concrete, and which facilitates drying, gives a higher resistance against thermal-shock and against chemical attacks.
Our line of Kilofast® concretes, includes materials with 40 to 95% Al2O3 and with diff erent SiC contents, which is to say, it spans a large range of materials capable of withstanding the work-conditions that appear in different points and different types of Ovens, so that we find the same potential as with our low-cement content concretes, with the advantage of being able to carry out a rapid heating process, with the accompanying energy savings that this implies.
The strength control of concrete in accordance with EHE-08
The possession of a recognised quality mark for the materials and deliveries of structural concrete implies advantages during the project and control in accordance with the new Structural Concrete Regulations EHE-08. The strength control has different acceptance criteria when a recognised quality mark for the concrete
The main aim of this paper is the study on the basic concepts of strength control through the Monte Carlo Simulation. The EHE-08 principles to take into account for the concrete manufacturer during the production process and delivery with acceptance probability are also considered in the exposed analysis. The influence of using a concrete with recognised quality mark in testing results and the testing conditions by repeatability and bias, are also examined. Both construction and autocontrol tests are analysed. Finally, other non-statisticals methods of control will be shown, as well as the decisions arising from the quality control.
Sewage sludge drying using the clinker kiln gases in Cemex España S.A. plant, Alicante
Cemex España S.A. has signed a collaboration agreement with the ‘Entidad Pública de Saneamiento de Aguas Residuales de la Comunidad Valenciana’, to develop a 57.000 TPY drying and valorization plant of municipal sewage sludge in Alicante (Spain). The drying plant uses the residual heat of the clinker cooler gases to dry the sewage sludge.
Promotion of biodiversity in quarry restoration processes: research and environmental education
The Yepes-Ciruelos quarry extends over more than 200 hectares in the semi-arid climate of central Spain. This quarry rehabilitation has been an opportunity to rehabilitate according to natural habitats and species. It has been made taking into account the commitments between Lafarge and WWF like ‘Conservation Partner’, in which the biodiversity is one of the most important goal.
The Torre Espacio in Madrid (3rd part)
The Torre Espacio (Space Tower), in Madrid, is one of the highest sky-scrapers in Europe. The building is located in the sky-scraper complex Cuatro Torres Business Area (CTBA) (Four Towers Business Area).
It is 236 m high and has 57 floors above ground level. These have a square shape in the base, which changes gradually as height increases to become eventually an ogive, following a curve represented mathematically by the cosine function.
Construction processes and installations non habitual in Spain have been used, e.g. high strength concretes, special methods to pump concrete pumping, self climbing forms or modular façades.
In the third part of the article the safety measures adopted in the execution of the structure are described, as well as the influence of climatic factors on safety, the assembly of the façade, the main facilities, the characteristics of the accesses and some details of the urban elements in the area of the building.