Study of optical microscopical of portland cement clinker according to different physicalchemical conditions
The article’s objective is to show the importance of the optical microscopical for the analysis of clinker. We will see how the optical microscopical not only contributes to give information about clinker’s quality but also about the process to manufacture clinker. Some interesting results have been achieved to optimize the process to obtain better quality clinkers this way. The results obtained have been analyzed with a limited number of samples of clinkers in Holcim-Yeles.
Initially, the study was based in the analysis according to the optical microscope and when we were progressing in the analysis others appeared as, for example, the compararison with parameters of production of kiln and the study according to XRD and SEM. The results found open a wide fi eld of research later as the study according to analysis XPS with XRD and SEM in a more representative number of samples.
About the EN 15743:2008 `supersulfated cement´
The basic content EN 15743:2008 ”supersulfated cement” (SSC) is presented. Origin, properties and applications of the product are also commented. SSC utilization is not permitted in Spain in structural concrete because this binder is not included in the national regulations of application (EHE-08).
Solubility Products and Stability of Calcium Sulpho-Aluminate Hydrates
Two calcium sulphoaluminate hydrates have been prepared and their composition were determined. The low sulphate form , the monosulphate hydrate, 3CaO·Al2O3·CaSO4·12H2O is relatively unstable. It is readily converted to the high sulphate form known as ettringite 3CaO·Al2O3·3CaSO4·32H2O. The solubility of both phases in pure water has been determined at 25 °C. Solubility products were determined from the solubility values and compared with that found in the literature.
EQUIPMENT PROVIDERS 1
X-Ray Inspection System closely examined
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EQUIPMENT PROVIDERS 2
Innovation and sustainability in cement packing. Our new equipments
Packing is friendly in environmental terms but Ventomatic has development in their medium capacity equipment, new developments to reduce cement dust (depressed hopper; self greasing) and mainly maintenance reduction in our new rotopacker machines.
We like to introduce you our new equipments: self supported packer, Ventocem packer, new Bu bag applicator and Policem palletizer.
Fast-track concrete for repairs in a continuously reinforced concrete pavement in Spain: `Y de Asturias´
The continuously reinforced concrete pavement connecting Oviedo, Gijón and Avilés, better known as `Y of Asturias´, was opened to traffic more than 34 years ago. In spite of the high traffic volume (70.000 vehicles/day), its performance to date has been very good. Only a few distresses have appeared in the pavement. To repair these broken slabs and punch-outs, three different types of fast-track concrete have been used. Traffic is allowed once compressive strength exceeds 15 MPa.
Two types are produced in a ready-mix concrete plant, one of them with CEM I 52,2N cement and the other one with CEM III/A 42,5N SR cement. The specified strength is obtained within 6 to 24 hours. The third type is a pre-dosed concrete, supplied in bags and mainly intended for small size repairs. It is mixed with water on site, traffic being allowed after 3 hours. All of them have been used in the few repairs done with very good results.
6th Ciment Català Seminar: industry contributions for a more competitive and sustainable economy
The cement, concrete and construction industries have a lot to contribute in the way out of the crisis. This could be the common message of the speakers of the 6th Ciment Català Technical Seminar, which analyzed the solutions offered by the industry for a recovery on solid ground.
Last 4th June, on the Cosmocaixa Barcelona Auditorium, around 300 people attended the sixth edition of the event, also focused on strengthening networking between the industry, the Administration and academic institutions.
The main discussion subjects were the value of infrastructures for economic development, the potential of concrete structures and architecture regarding efficiency, the sustainability of concrete pavements and the prospects related to the use of alternative fuels in the industry.
Study of the CO2 Sink Effect of Cement Based Materials
One of the main problems related to climate change is the greenhouse effect produced by the partial absorption of infrared radiation emitted by the Earth from the so called 'greenhouse gases', including carbon dioxide.
The work proposed here is part of the initiatives undertaken by the cement industry to help to reduce the greenhouse effect and the studies conducted to estimate the contribution of cement based materials in the fighting against climate change. For this purpose, the extent of the CO2 sink eff ect of concrete
carbonation is studied.
The United Nations Framework Convention on Climate Change defines sink as "any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere”.
First cement company in the world to implement a program to assure the responsible purchasing of forest’s products for industrial use
Lafarge Cementos has been the first Cement industry in the world to receive the certification FSC for Cement Paper bags and pallets. Through this action we are collaborating with WWF in the sustainable use of the planet forests and the communities around them, in line with Lafarge Group policies and corporate
Lafarge Cementos has implemented a program to manage the responsible purchasing of forest’s products that we use in our production process as Kraft paper for bags and wood for the pallets, in order to assure a legal and sustainable source of the wood. Under this program scope, during the purchasing process, we give priority to the products certified by the system FSC (Forest Stewardship Council) supported by the main environmental and social ONG’s in the World. FSC Certification gives the best guarantee of the legal, sustainable and controlled origin of the wood.
Through this program Lafarge Cementos supports the responsible use of the forest from the social y environment points of view and contributes to the forest conservation and is the first company in Cement industry in Europe and in the whole World that uses paper bags and pallets certified by FSC.
With the successfully implementation of this program we have launched a strong message of our commitment with the responsible use of the forest and contribute to differentiate our products from the competitors’ ones.
The Navia viaduct (2nd part)
The current trend to the construction of long viaducts of great longitude, originated by both the improvement of the standards of quality of the transport infrastructures and for environmental constraints, obliges to industrialize their construction. Deck execution by means of precast segments is a system broadly used throughout the world, although in Spain its development is small.
In the construction of the Navia viaduct this system has been used, for both the access viaducts 75 m long and main span 160 m long. By providing structural continuity to the deck and using the same precast elements for the whole viaduct, a simplification of both the production and the assembly processing has been obtained, resulting in a reduction of execution times and costs.
The design and construction of the Navia viaduct are fplaced inside a line of work line started by FCC Construction, for the construction of viaducts by means of precast segements, initially intended for viaducts of average spans that in this case has been extrapolated to long spans. In the second part of the article some data about concretes used in the viaduct are provided and the construction process is described.