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Innovative Calculation Method of the Productivity of Vibrating Screens Used in Mineral Aggregates Sorting

Abstract

In the process of preparing cement or asphalt concrete – frequently used in ways, roads and access road construction, it is necessary to sort out poly-dispersed granular mixtures from bilge deposits or quarries. The mechanical sieving performs the separation of the granules on dimensional sorts (the size of graded grains can be 1... 70 mm) by means of machines called screeners. In the case of vibrating screeners, the working body (the sieve) presents a vibratory movement that ensures a high productivity of the screening machine and a very good quality of the final products obtained. The article studies the productivity of the vibrating screen used in mineral aggregates sorting process obtained by different methods. In this regard, a pragmatic simplified formula called Pragma is proposed, a formula which was tested with good results in situ experiments done on a bi-mass vibrating screen in a pilot station.

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Ecological Solutions Applied to Hot Mix Asphalt

Rezumat

Mixturile asfaltice sunt materiale compozite realizate din amestecuri de agregate naturale sau artificiale, filer și bitum, avȃnd la baza dozaje bine stabilite și o tehnologie adecvata astfel încȃt să rezulte un material rutier cât mai durabil posibil.

În urma studiilor efectuate pe plan internațional cât și pe plan național, s-a demostrat că se pot înlocui cu succes agregatele naturale cu zguri siderurgice sau de oțelărie, care prin prelucrare și sortare la dimensiuni necesare sunt cele mai adecvate din punct de vedere al proprietăților fizico-mecanice.

Mixturile asfaltice ecologice obținute prin înlocuirea agregatelor minerale cu zguri siderurgice vor intra în alcătuirea structurii rutiere, începand cu studiul pentru un strat de bază. Pentru evaluarea performanțelor mixturilor asfaltice în care agregatele naturale sunt înlocuite cu agregate artificiale, se va studia o mixtură asfaltică pentrul stratul de bază respectiv AB 31.5 pentru care se vor face încercări pentru trei rețete de mixturi asfaltice: mixtura asfaltică cu agregate minerale de carieră, mixtura asfaltică în care agregatele minerale vor fi înlocuite în proporție de 50 % cu zguri siderurgice și o mixtură asfaltică care va conține zguri siderurgice în proporție de 100%.

Încercările de laborator se vor face în cadrul Laboratorului de Drumuri din cadrul Facultății de Căi Ferate, Drumuri și Poduri, Universitatea Tehnică de Construcții București; rezultatele obținute vor fi detaliate sub forma de tabele și grafice, concluziile urmând a face aprecieri asupra performanțelor mixturilor asfaltice ecologice. Astfel, se vor stabili performanțele mixturilor asfaltice ecologice comparativ cu calitățile mixturilor asfaltice clasice, folosind următoarele încercări: determinarea densității aparente, a volumului de goluri, caracteristicilor Marshall și a modulului de rigiditate.

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The use of expanded clay aggregate for the pretreatment of surface waters on the example of a tributary of Lake Klasztorne Górne in Strzelce Krajeńskie

Abstract

The paper presents a proposal for the treatment of river water based on expanded clay (ceramsite). It is a lightweight mineral aggregate containing components relative to phosphorus adsorption (calcium, iron, manganese, aluminum). A pilot plant on a fractional technical scale was built on a nutrient rich (phosphorus up to 0.4 mg dm−3, nitrogen up to 10.0 mg dm−3), small (mean annual flow about 0.04 m3 s−1), natural watercourse (Młynówka River, a tributary of the Otok Channel, Noteć basin, the municipality of Strzelce Krajeńskie). The monitoring included quantitative and qualitative measurements of the water stream in 2014-2015. On the basis of the examinations, the calculated effectiveness of ceramsite filters in removing major contaminants from water was: for total nitrogen 5-6%, phosphorus 12-16%, and for suspensions 17-29%. The effectiveness of the treatment is highly influenced by hydraulic load, so this type application on a full-scale should occupy a sufficiently large volume. Taking into account simplicity of performance, ease of operation and low cost of construction and maintenance, such pretreatment plants based on expanded clay would seem to be a promising tool for the protection of surface waters in catchments of small rivers and streams.

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Assessment Gravel Aggregate Reactivity With Alkalis In Relation To Methods Of Test

Concrete Research , 40, 556–562, 2010 8. PN-92/B-06714-46 Mineral aggregates – Testing – Determination of alakaline reactivity by rapid method (in Polish), 9. ASTM C 289-94 Standard Test Method for Potential Alkali Silica Reactivity of Aggregates (Chemical Method), 10. PN-B-06714-34:1991/Az1:1997 Mineral aggregates – Testing – Determination of alakaline reactivity (in Polish), 11. ASTM C 227-10 Standard Test Method for Potential Alkali Reactivity of Cement- Aggregate Combinations (Mortar-Bar Method), 12. ASTM C1260 – 07 Standard Test

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Asphalt Mixtures with Limestone Aggregate for Base Layer

Abstract

Asphalt mixtures are mixtures of mineral aggregates, filler, bitumen and eventually additives in proportions determined by recipe designed in the laboratory. Asphalt mixtures used as base course are bituminous concrete.

The natural aggregates are granular materials of mineral origin that come from natural or artificial crushing of the rocks. In our country there are the various rocks: eruptive or magmatic rocks, metamorphic rocks, sedimentary rocks.

To the category of sedimentary rocks belong limestone. Sedimentary rocks are characterized by relatively high porosity and a pronounced stratification, which causes mechanical resistance to be low and vary by direction of load. Due to the structure less dense and weaker mechanical resistance, the limestone are used less in heavy traffic pavement structures.

This paper presents an asphalt mixture recipe for the base layer developed in the Laboratory of Roads from Technical University of Civil Engineering Bucharest (TUCEB), using limestone aggregates extracted from Hoghiz Quarry. The paper contains laboratory test results to determine the recipe and laboratory findings leading to the schedule of product.

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Effect of Aggregate Gradation on the Stiffness of Asphalt Mixtures

. VAVRIK, W. R. 2002. Bailey method for gradation selection in hot-mix asphalt mixture design , Transportation Research Board, National Research Council. VAVRIK, W. R., PINE, W. J., HUBER, G., CARPENTER, S. H. & BAILEY, R. 2001. The bailey method of gradation evaluation: the influence of aggregate gradation and packing characteristics on voids in the mineral aggregate (with discussion). Journal of the Association of Asphalt Paving Technologists , 70.

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Investigation of Hot In-Place Recycling Effects on Hot Mix Asphalt Pavement

Sulawesi, Indonesia. Roberts, F. L., Kandhal, P.S., Brown, E.R., Lee, D.Y., and Kennedy, T.W. (2009). “Hot Mix Asphalt Materials, Mixture, Design and Construction”. National Asphalt Pavement Association Research and Educational Foundation, Lanham, Maryland, USA. Roque, R., Birgission, B., Tia, M., and Nukunya, B. (2002). “Evaluation of Superpave Criteria for VMA and Fine Aggregate Angularity: Voids in Mineral Aggregate (VMA)”. Florida Department of Transportation Report No. WP10510865, Vol. 1 of 2. Von Quintus, H.L. and Simpson, A.L. (2002

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Methods of enlarging material to the concentration table

). Operation of double single-mass drives for concentrating tables. Conference materials, 4th International Technique of Building Technique, Krynica. Góralczyk, S. Blaschke W. Kozioł, W. Sobko, W. (2016). The use of FGX air concentration tables for cleaning broken natural aggregates. Mining Science-Mineral Aggregates, vol. 23 (1), 37-46. Łuszczkiewicz, A. and Kaczmarek B. (1992). Phisicochemical Problems of Mineral Processing. 25, 123-132. Pilch, W., Stachrsk, J., Sztaba, K. (1990). Investigations and utilization of heavy minerals from Baltic beach sands

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Fractal Dimension for the Characterization of the Porosity of Asphalt Concretes

. 22. R. Cominsky,et al., SHRP-A-407. The Superpave Mix Design Manual for New Construction and Overlays, National Research Council, Washington, DC, 1994. 23. J. Goode, L. Lufsey, A new graphical chart for evaluating aggregate gradations, pp. 176-207, 1962. 24. G. Huber, T. Shuler, Providing Sufficient Void Space for Asphalt Cement: Relationship of Mineral Aggregate Voids and Aggregate Gradation, Effects of Aggregates and Mineral Fillers on Asphalt Mixture Performance, 1992.

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The Influence of the Carbo-Glass Geogrid-Reinforcement on the Fatigue Life of the Asphalt Pavement Structure / Wpływ Zbrojenia Siatka Weglowo–Szklana Na Trwałosc Zmeczeniowa Asfaltowej Nawierzchni Drogowej

Naukowych w latach 2005-2007. 8. W. Grzybowska, J. Wojtowicz, Ł. Fonferko, Application of geosynthetics to overlays in Cracow region of Poland, Proceedings of the Second International RILEM Conference, Reflective Cracking in Pavements, pages 290-299, Liege, 1993. 9. W. Grzybowska, P. Zieliński, and J. Górszczyk (współpraca), The Monograph: Influence of material parameters on the durability of mineral-aggregate mixtures in road pavements, for different load conditions [In Polish], Projekt badawczy Nr 8.TO7 E.043.21 finansowany przez Komitet

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