QUARRIES AND RAIDS
Conclusions of UEPG report on water management in European aggregates sites
The management of water in the aggregates industry is becoming a very critical issue due to the existing pressures on this resource throughout Europe, to the impact it has on the industry and by the new EU policies applied to its management that make it increasingly important to carry out an integrated approach by aggregates companies.
Between 2016 and 2017, the European Aggregate Producers Association (UEPG), has coordinated a European-wide survey and report on the patterns of consumption, recycling and efficiency that are applied by companies.
This work has been carried out under the coordination of the author, with the participation of more than 100 extraction sites from different EU countries, has led to the preparation of a complete report of results and recommendations, which is summarised in the present work.
The conclusions can be extrapolated to all aggregate sites and allow improving water management in the whole sector.
Rheological behaviour of fresh portland cement pastes with and without silica fume and siliceous filler
The rheological behavior of fresh portland cement pastes (CP) with different chemical and potential mineralogical compositions was analyzed alone and when were blended with siliceous mineral additions in origin and silicic character with different morphology and fitness (the first quartz (C), fully crystalline, and the second silica fume (SF), almost totally vitreous and also with the average size of its spherical and hollow particle extremely small, which gives it very pozzolanic properties that are not impaired by the small fraction of cristobalite that also constitutes it).
Trials were conducted during latent hydration at 25 ºC. The findings showed that apparent viscosity was higher in the PC with low C3A and high C3S content, consequently, the Na2Oeq.(%) content of everyone also contributed very signifi cantly to the point of being its main responsible, with and without these two siliceous mineral additions used: filler C and pozzolan SF. Furthermore, these siliceous mineral additions were likewise observed to affect fresh paste rheology in both types of PC, depending, firstly, on whether or not they were pozzolanic, and secondly, on their morphology and particle size and the type of PC.
These additions stimulate hydration in one way or another depending on their chemical character (type and degree), morphology and size of their particles and speed of its pozzolanic activity, which translates directly on the rheological properties their fresh cement pastes.
Success on a huge scale
Precise planning, perfectly put into practice: the conversion of an electrostatic precipitator into a baghouse with EMC technology at a cement plant in the Thai province of Saraburi marks a milestone in the history of Scheuch. Decades of experience flow into the project, from the planning stage right up to the commissioning of the filter, to find the best solution for the SCG requirements.
The costumer SCG (Siam Cement Group) also benefi ted from this remarkable project in financial terms: The order has proven that such retrofit concepts can improve a plant with obsolete filter systems to the latest
clean air technology at low investment costs. With EMC the global player Scheuch is setting new standards in pressure loss, cleaning pressure, bag service life, and bag length. The sum of its advantages over other systems, makes EMC technology the modern benchmark of technical innovation.
EQUIPMENT PROVIDERS 2
System of measurement of emssions to the atmosphere
Depurfiltech, S.L, as an integral development company in the manufacture and commercialization of articles for the industry in general related to bag filters (dust and gas collection), is the offi cial distributor of the products of the Italian Autel, Srl., (probes, sequencers, timers, electro-valves, membranes, pilot boxes, etc.).
We present below an eff ective method, for the detection of emissions to the atmosphere, to control the state of the filtering elements inside the filter (bags/artidges), being able to determine the amount of residual dust after the filter, the possible ruptures of the fi lter bags, reducing the maintenance costs, detecting the exact point (row/column), where the problem of the filter element is found.
We have at your disposal, a technical and professional team which will clarify any questions that may arise.
EQUIPMENT PROVIDERS 3
Shrinkage-compensating concrete with Mapecrete System
Concrete made with portland cement is, nowadays, a construction material of habitual use, for its versatility and cost. An inherent property of concrete is shrinkage due to the decrease in volume that it experiences for different causes. Depending on the factors that cause it, we have several types of shrinkage (plastic, endogenous, thermal, by carbonation or by drying), the latter being the one that normally has a greater magnitude.
The drying shrinkage is generated by the evaporation of the free water contained in the pores of the hardened concrete, which causes a volumetric contraction of the same. If we have restriction of the movement in the concreted element, fissure could occur when the tensile forces generated by this contraction exceed the tensile strength of the concrete, generally low.
One solution to avoid the cracking is the use of shrinkage-compensating concrete with Mapecrete System.
EQUIPMENT PROVIDERS 4
Filtration in the cement industry. A strategic issue
As a reason of the lots of dust generated at every stage of the cement production and due to the impact filtering equipment and installations have in its processes, filtration on cement industry becomes a strategic issue that needs to be faced with the support of an experienced partner.
Thanks to its long expertise in filtration and to its depth knowledge of the cement sector by working with hundreds of producers worldwide, AAF, S.A. has developed a wide range of solutions and services to meet industry’s requirements and needs.
From turnkey projects to support main cement processes to nuisance fi lters that enhance workflow and operational productivity, AAF-SA span the entire value chain of cement production, guaranteeing every step thanks to its field services management, that support customers during the full life cycle of the solutions, and as a result of in-house manufacturing that assure quality by the full control over production.
A first approach to 3D printing: future prospects of cement-based materials
One of the construction technologies which are now being focused is the 3D printing, also known as additive manufacturing. A good example was the pedestrian footbridge built in Alcobendas (Madrid) last year, made with 8 precast concrete elements assembled on-site to reach the 12 m long and 1,75 m wide of such infrastructure. This case shows the enormous possibilities of this technology by the incoming years both for housing and civil engineering works. Two main challenges will surely be on the capacity to get big elements to optimize the processes and what materials will impose on construction industry.
Current status of the CO2 capture technology in the cement industry
This work describes the status of the CCS technologies that are currently used to decrease the CO2 emissions in the cement industry. In addition, a description of the current status of CCS in the world is accomplished. Actually, there are 17 large-scale CCS facilities operating globally and four coming on stream in 2018 accounting for a CO2 capture capacity of 37 million tonnes per annum (Mtpa).
The main research and technology development carried out in Spain is also described. This includes the Elcogas
precombustion tests, the oxicombustion facilities located at Fundación CIUDEN, the calcination-carbonation technology developed at INCAR-CSIC, and the Chemical Looping Combustion research carried out at ICB-CSIC.
Thin bonded concrete overlay for the rehabilitation of the concrete pavement of an urban boulevard in the municipality of Beniparrell (Valencia)
Escoles street, is one of the main streets of Beniparrel, in Valencia. This street holds the House of Culture, the municipal sport center, as well as the future medical center. Therefore, this boulevard supports a significant traffic of light vehicles, estimating an average daily intensity of heavy vehicles not exceeding 30.
Street paving of the residential city center of Beniparrell began in 1980. Most of roadswere paved in concrete and the sidewalks were paved with precast concrete tiles. After more than 35 years, most of these streets remain in good condition, although some of them, mainly those subjected to a higher traffic intensity, are deteriorated and present cracking and breaks of edges and corners.
Taking advantage of the financial support given by the Plan of Roads 2016-2017 of the Provincial Council of Valencia, the city of Beniparrel decided in mid-2016 the renewal of this road through the execution of a thin bonded concrete overlay of 8 cm thick on the existing concrete slab. To ensure the adhesion between both layers, the existing pavement was previously milled and a latex union bridge was applied. The surface finishing was achieved by mechanical troweling, avoiding excessive polishing of the surface, in order to obtain a texture similar to that existing in the rest of the streets of the municipality that were built in the 80s.