Asphalt Concrete Production Research Articles

The Ceramic Dust Utilization at the Asphalt Mix Production

The possibility of using industrial waste - ceramic dust in the production of asphalt concrete is considered. The characteristics of ceramic dust and building sand are compared. The analysis of the physicomechanical characteristics of the asphalt concrete mix is made. This mixture has a different content of ceramic dust (10%, 30%, 50%) of the amount of building sand. The samples made from this mixture were tested in a certified building laboratory. It is shown that the use of ceramic dust in the composition of the asphalt concrete mixture as a filler does not significantly change either the structure or the physical and mechanical properties of the latter. The possibility of using in construction practice asphalt concrete with a 50% replacement of sand with ceramic dust is proved.

ИСПОЛЬЗОВАНИЕ ОТХОДОВ РЕЗИНЫ ДЛЯ МОДИФИКАЦИИ ВЯЖУЩЕГО В АСФАЛЬТОБЕТОНЕ

The development and implementation of road surfaces resistant to temperature extremes and high technogenic loads is one of the important tasks for road workers. These surfaces must be economically viable for production. Since the known methods for improving the physicomechanical properties of a binder for asphalt concrete involve the introduction of expensive foreign polymers. Rubber crumb, being a waste of production, allows to solve the problem with the disposal of used tires, and the cost of such a modifier for road bitumen is lower than foreign polymers. The article describes an example of using a rubber crumb to modify the road binder in asphalt concrete. The compositions of bitumen-rubber suspensions, the determination of the physicomechanical properties of a modified binder are described. The test results of asphalt concrete with a bitumen-rubber binder are given. A comparative analysis of asphalt concrete on bitumen oil road viscous and asphalt concrete on a modified binder is carried out. The purpose of this work is to develop a theoretical justification and practical application of a bituminous-rubber binder obtained by combining oil road bitumen with rubber crumb. Material processing takes place in the microwave field. The resulting bitumen-rubber composite surpasses viscous petroleum bitumen in physical and mechanical properties and is suitable for use as a binder for the production of high-quality asphalt concrete.

Using Steel-Smelting Slag as a Raw Material Component in the Production of Asphalt Concrete

The possibility of using polydisperse steel-smelting slag for the production of type B asphalt concrete is investigated, the possibility of its use as a mineral powder, crushing screening and crushed stone is considered. As a result of the study, it was found that a promising area for the use of slag raw materials in the technology for the preparation of asphalt mixes is: as a mineral powder - without additional processing steps; crushing screening - with the development of additional technological operations. The use of raw materials as crushed stone is impractical because of the high average density of the final asphalt mixture. Based on the test results, the characteristics of the fatigue properties of asphalt concrete from fine-grained dense mixtures of type B made on mineral powders from slag and limestone were obtained. It was established that at the initial moment, a large number of cycles to failure are characterized by compositions on slag powder, however, samples from this series tested after 45 days showed a significant rigidity increase and were destroyed earlier than similar samples on limestone. Obviously, this phenomenon is associated with an increase in the brittle properties of the material due to the formation of crystallization-condensation bonds in the structure of asphalt concrete containing slag.

Inventory of the Release of Harmful Substances and Evaluation of the Efficiency of Dust and Gas Treatment Plants from Asphalt Concrete Mixing Plants

This article provides time standards and calculation methods for the purpose of studying air pollution from industrial facilities. Calculations of technological equipment and the efficiency of the dust and gas treatment plant. The results of inventory, regulation of emissions of pollutants entering the atmosphere are considered. Questions on the study of equipment for cleaning dust - gas, methods for improving and improving the efficiency of the equipment are highlighted. The methods for determining the composition and quantity of pollutants in the off - gas flows are given: theoretical (balance), computational and analytical (experimental), and reporting and static. The procedure for conducting an inventory of sources of emissions on the territory of the enterprise, the number and composition of emissions of pollutants. Analyses of harmful substances entering the atmosphere from the production of asphalt concrete, measures to improve the efficiency of dust and gas treatment plants were performed. The process of asphalt mixing and production capacity of the enterprise are studied Samarkand asphalt concrete production.

The Relationship of the Asphalt Mixtures Composition and Physical Mechanical Characteristics of the Coating

In the course of the work performance the following surveys were carried out: the analysis of the information assurance of the asphalt concrete mixtures production quality, the study of the relationship between the composition of asphalt concrete mixtures and the physical and mechanical characteristics of the coating. This paper presents the results of the analysis of the two types asphalt concrete mixtures qualitative composition and its effect on the physical, mechanical and technological characteristics of the coating. It is established that the deviation of asphalt concrete mixtures in composition from the required values ​​leads to their under-compaction in the coating. It was also found that the increase in the number of inconsistencies in the composition of the asphalt concrete mixture leads to the increase in physical and mechanical characteristics that differ from the requirements of GOST 9128-2013 and GOST 31015-2002. The amount of bitumen on the asphalt concrete main characteristics, the data from the existing AP in the Belgorod Region were used as the information base in assessing the influence of granulometry of the asphalt concrete mineral part. Analysis of the particle size distribution was carried out using the laser analyzer for asphalt concrete AP 7 / 35B. The obtained data will be the basis for further study of the various parameters influence on the asphalt mixes properties, as well as improving the efficiency of the asphalt mix production control system.

Utilization of Industrial Waste Products in the Production of Asphalt Concrete for Road Construction

Abstract The utilization of industrial waste products to produce asphalt concrete for road construction was investigated. Aggregates were partially replaced with aluminum slag (AS) and crushed ceramic tiles (CCT) at 10%, 20%, 30%, 40%, and 50% by weight. Physical tests were performed on the aggregates, while a flash and fire point test as well as penetration tests were carried out on the bitumen. Similarly, Marshall stability tests were conducted on cylindrical specimens of the asphalt concrete. The average values of 18.88 and 30.69 obtained for the aggregate impact value (AIV) and aggregate crushing value (ACV) were satisfactory for road surfacing when compared with the specification. Marshall stability values of 10.84 KN, 4.27 KN, and 3.21 KN respectively were obtained with 30%, 20%, and 50% partial replacements with AS. The percentages were suitable for heavy, medium and light traffic when compared with the Marshall design criteria provided by the Asphalt Institute. The use of aluminum slag and crushed ceramic tile could reduce the large volume of industrial waste and the cost of pavement construction and maintenance.

The Impact of Bitumen Roofing Production Waste (BTw) on Physical Mechanical Properties of Concrete

This article presents how concrete properties would change if part of a coarse aggregate (granite crushed stone) were replaced with bitumen roofing production waste (BTw). BTw is a huge ecological problem because these wastes are generated in large quantities when replacing old bitumen-based roof tiles. Wastes are also produced during the production of bituminous roof coatings. Usually BTw are stored in landfills or it is attempted to use/dispose them in the production of asphalt concrete. There are very few works which analyse the impact of BTw on the properties of cement materials, although the impact of these wastes on the properties of cement materials could be beneficial because BTw consist of aggregate, granules, bitumen and fibers. In order to use BTw, standard concrete samples were first formed, then 5/16 granite fraction was replaced with BTw in amounts of 2%, 4% and 6% by weight The amounts of limestone Portland cement, fine aggregate (sand), water and superplasticizer in the concrete mixtures were constant. The new generation of superplasticizer based on polycarboxylates was used in mixtures. The following concrete properties were identified and analyzed: density of the mixture, flowability, density of concrete samples, water absorption, compressive strength, forecasted frost resistance, and microstructure studies were conducted as well. The results of the studies showed that BTw can be used in small amounts, i. e. up to 6%, then the density of the samples slightly decreased (by 2.4%) and water absorption increased (by 0.7%). Compressive strength, after replacing 2% granite crushed stone, decreased by 2.4%. However, gradual addition of the amount of BTw resulted in more closed pores that improved the frost resistance of the concrete. When 6% of bulk filler was replaced with BTw, closed porosity, compared to control samples, increased by 54% and forecasted frost resistance - by 26%. Microstructure analysis showed that with 6% BTw a dense cement stone structure was formed, showing the hydrates of portlandite and CSH.

Equipment desing automation at asphalt-concrete production modernization

The relevant task in the field of road construction and maintenance is gradual transition to the production of asphalt-concrete mixtures on polymer-bitumen binders. Most asphalt-concrete plants of small and medium capacity consider this transition as challenging due to a relatively high cost of the specialized equipment for polymer-bitumen binders production. Most proposed techniques involve the utilization of colloid mills. The practice of such mills operation shows that production lines experience long downtime periods due to the necessity of preventive maintenance and repair. A promising direction in polymer-bitumen binders manufacture is to use polymer waste materials for the bitumen modification. This provides the reduction of the modified binder costs and the solution of environmental problems. The paper deals with the problem of asphalt-concrete plants modernization to obtain polymer-bitumen binders in its own production using agitated mixers common in the chemical industry. Optimization problem is formulated for design and operating parameters of such equipment to provide required quality indicators for the resulting polymer-bitumen binders. Algorithmic and software assistance is developed to solve the set problem. The proposed technical solutions were tested when solving the modernization problems regarding the process diagram of the asphalt-concrete plant to release products on polymer-bitumen binder of its own production.

Ecohygienic assessment of the operational impact of the enterprises for asphalt concrete production on the state of the environment taking into account the requirements of domestic legislation and EU directives

Ecohygienic assessment of the operational impact of the enterprises for asphalt concrete production on the state of the environment taking into account the requirements of domestic legislation and EU directives

Carbon footprints calculator of highway pavement rehabilitation: The quantification of carbon emissions per unit activity

Carbon dioxide that emitted throughout the construction lifespan is crucial from development of design, construction, up to demolition stage. Focusing in the rehabilitation of highway pavement, the activities that normally involved are from milling, roller up to dumping the wastes asphalts. The aim of this paper is to estimate the carbon footprint emission in unit of tonnes for carbon dioxide equivalents (t CO2-eq/km-lane). The case study involved based on five selected projects for north–south bound expressway of Malaysia. The results show that highest carbon footprint were from the Mill and Pave 250 mm (MP 250) with 117.94 t CO2-eq/km-lane. This is due to its depth of pavement with 140 mm dense bituminous macadam, 60 mm asphalt concrete base course and 50 mm asphalt concrete wearing course as compared as other Mill and Pave. The result followed by MP 200, MP 110 and MP 50 at 95.19, 54.10, and 27.37 t CO2-eq/km-lane respectively. The critical activities involved during the construction shows the asphalt concrete production as the highest generation of emission with 53.78 t CO2-eq/km-lane, followed by lorry transportation of asphalt waste, lorry transportation of asphalt concrete, fuel consumption from machineries, neomed coat, and water consumption with the value of 28.58, 24.50, 10.83, 0.23, and 0.01 t CO2-eq/km-lane respectively. The results from this study considered as references guidelines for carbon footprint calculator to calculate emission as compared to other expressway in Malaysia.

Granulated asphalt mix based on industrial and domestic waste

The paper presents the results of experimental studies to identify the possibility of using large-tonnage industrial mineral waste in the production of asphalt concrete mixtures. As a raw material for the production of asphalt used phosphogypsum - waste production of phosphoric acid, resulting from the processing of apatite. The reserves of this product are measured in millions of tons and are constantly replenished, stored in open dumps, representing a serious threat to the environmental situation in the surrounding areas. Phosphogypsum is a mineral powder material, the dispersion characteristics of which correspond to the mineral powder in the production of asphalt concrete. The method of production of granulated as-falto-concrete mixture developed by the authors of the article by the method of rolling involves the use of a significantly higher content of expensive mineral powder in comparison with typical mixtures. Therefore, the use of cheap phosphogypsum for these purposes is very attractive. However, the first attempts to obtain a granulated product based on phosphogypsum were unsuccessful - the asphalt-concrete mixture did not withstand the effects of moisture. Further studies allowed us to solve the problem of material resistance by modifying bitumen with polyethylene terephthalate, one of the most common household plastic waste. The subject of the article is devoted to the development of prescription and regime parameters of the process of obtaining new material. Test methods for asphalt concrete are strictly standardized in connection with which standard techniques were used. As a result of the research, an asphalt-concrete mixture was obtained, surpassing typical materials in many performance characteristics and allowing to solve a global environmental problem.

Analysis of the Mechanical Behaviour of Asphalt Concretes Using Artificial Neural Networks

The current paper deals with the numerical prediction of the mechanical response of asphalt concretes for road pavements, using artificial neural networks (ANNs). The asphalt concrete mixes considered in this study have been prepared with a diabase aggregate skeleton and two different types of bitumen, namely, a conventional bituminous binder and a polymer‐modified one. The asphalt concretes were produced both in a road materials laboratory and in an asphalt concrete production plant. The mechanical behaviour of the mixes was investigated in terms of Marshall stability, flow, quotient, and moreover by the stiffness modulus. The artificial neural networks used for the numerical analysis of the experimental data, of the feedforward type, were characterized by one hidden layer and 10 artificial neurons. The results have been extremely satisfactory, with coefficients of correlation in the testing phase within the range 0.98798–0.91024, depending on the considered model, thus demonstrating the feasibility to apply ANN modelization to predict the mechanical and performance response of the asphalt concretes investigated. Furthermore, a closed‐form equation has been provided for each of the four ANN models developed, assuming as input parameters the production process, the bitumen type and content, the filler/bitumen ratio, and the volumetric properties of the mixes. Such equations allow any other researcher to predict the mechanical parameter of interest, within the framework of the present study.

Moisture sensitivity and mechanical performance assessment of warm mix asphalt containing by-product steel slag

Warm Mix Asphalt (WMA) has recently become an attractive alternative in pavement engineering due to its potential for significant reduction in energy consumption and carbon footprint of asphalt industry; however, concerns have been raised regarding durability of material and potential to moisture damage due to lower mixing and compaction temperatures. Furthermore, steel slag which is mostly disposed in landfills as waste material could be an appealing option as substitute of natural aggregates for asphalt concrete (AC) production because of its adequate affinity with asphalt binder. The aim of this study is therefore, to assess whether the integration of basic oxygen furnace (BOF) steel slag into Sasobit WMA technology would indicate satisfactory performance in terms of moisture susceptibility. This paper also examines if BOF slag WMA mixture can provide acceptable mechanical performance to be used as a more sustainable approach for pavement construction.To capture short-term moisture damage resistance of BOF slag WMA, specimens prepared with two Sasobit dosages were subjected to two different testing methods. Modified Lottman test and boiling water test using an image analysis technique were performed to compare moisture susceptibility and stripping resistance of BOF slag WMA and HMA (hot mix asphalt) samples with conventional mixtures. Dynamic creep test, Hamburg wheel-track device and resilient modulus test were then conducted on specimens to evaluate mechanical behavior of BOF slag WMA in comparison with BOF slag HMA and another type of WMA mixture prepared with natural aggregates.Findings showed that BOF slag WMA provided significant resistance to short-term moisture damage and therefore, could be considered as durable bituminous mixture when compared to conventional asphalt mixtures. Furthermore, BOF steel slag HMA/WMA exhibited superior mechanical behaviors compared to limestone HMA/WMA mixtures, implying that steel slag could be an effective alternative as pavement material.

Moisture resistance and compactibility of asphalt concrete produced in half-warm mix asphalt technology with foamed bitumen

Current regulations regarding emissions, as well as the efforts focused on reducing energy intensity of building materials production create a need for implementing new road construction technologies. Particular attention is being paid to the lowering of asphalt concrete production temperature, which is about 160°C. In response to this need warm mix asphalt (WMA) technologies have been developed which allow producing asphalt mixes at temperatures about 20–30°C lower than those of conventional methods. However, it was only after half warm mix asphalt (HWMA) was introduced that the mixing temperature of asphalt concrete with foamed bitumen could be reduced by as much as 60°C. Asphalt pavements constructed with HWMA may have a reduced service life and lower resistance to environmental factors (e.g. water). This paper presents the results from the tests with one freeze cycle and from the moisture sensitivity analysis conducted for the low-temperature asphalt concrete (AC 8) with foamed bitumen and the control mix produced according to conventional hot mix asphalt technology. It was found that the modification of 50/70 bitumen (before foaming) with the addition of 2.5% FT synthetic wax had a beneficial effect on the properties of asphalt concrete mixes under investigation. The ITSR indices were compared having been determined in accordance with procedures based on European and AASHTO standards that are widely used in Poland. The analysis was extended to include the compactibility evaluation of low-temperature bituminous mixes and the impact of air voids on the mechanical parameters. The foamed asphalt concrete modified with 2.5% FT wax was found to satisfy the requirements for moisture resistance determined during the test with one freeze cycle.

Energy Saving Additives «RAA WAC» for Production of Warm Asphalt Concrete

For the last 15-20 years in Europe and in the USA the new technologies allowing to reduce temperature of hashing and consolidation of the asphalt concrete mix prepared on viscous bitumen by 20-40 °C were developed. Thus characteristics of a covering in comparison with use of traditional hot asphalt concrete don't worsen.One of ways of achievement of effect is application of special chemical additives.Results of researches of influence of the additives developed by authors together with the enterprise of "Selena" for production of warm asphalt concrete of the series «RAA WAC» on properties of bitumen and asphalt concrete in comparison with a known additive of Evotherm J1 are given in the real work.It is established that the studied additives at increase of their concentration in knitting a little reduce conditional viscosity of bitumen, raise tensile properties at a temperature of 25 °C, practically don't influence softening temperature.

Performance of Hot Mix Asphalt Concrete Produced with Coarse Recycled Concrete Aggregate

AbstractThis paper evaluates the replacement of natural aggregate coarse fraction for recycled concrete aggregate (RCA) in hot mix asphalt (HMA) concrete production, an area in which studies are recent and scarce. Crushed stone coarse aggregates (CSCA) were replaced by RCA with a 30 MPa compressive strength in the following percentages: 0, 25, 50, 75, and 100%, and mixed with asphalt cement (AC) 50-70. Volumetric and mechanical properties resulting from the Marshall mix design method, along with permanent deformation and durability by the moisture-induced damage test (Lottman), were analyzed. The results indicate that, although RCA shows higher absorption, higher Los Angeles abrasion, and lower density than the crushed stone aggregates, the mixtures showed satisfactory results for use as an asphalt concrete surface layer on low-volume roads. Wheel tracking tests presented permanent deformations ranging between 4.4 and 9.3%. It was also perceived as an adhesiveness improvement in the RCA mixture. The resul...

Metallic elements in PM2.5 in different functional areas of Korea: Concentrations and source identification

Both PM2.5 mass concentration and its chemical composition are a great concern to human health. In this study, the concentrations of PM2.5 and their metallic elements were measured to identify the characteristics and to trace sources at two different functional areas, a residential and a cement industrial area. The average PM2.5 concentrations were not significantly different between the two sites, but their chemical compositions were clearly different. Crustal elements in PM2.5 were significantly higher in the residential area, while the concentrations of metals typically emitted from anthropogenic sources were generally higher in the cement industrial area. Crustal elements often increased during spring in the residential area due to the blustery weather with high wind speeds; however, most metallic elements were enhanced during winter in the cement industrial area. Principal component analysis was used to trace the sources. Soil re-suspension, traffic-related sources, and asphalt concrete production were identified as the main sources of PM2.5 in the residential area, while the cement industry, Ni–Cr plating industry, and other industrial activities were identified in the cement industrial area.

A wall heat transfer correlation for the baffled-rotary kilns with secondary air flow and recycled materials inlet

The increasing use of the baffled-rotary kiln equipment in many innovative materials processing industrial applications suggests examining the heat transfer phenomena in order to improve the multi-phase flow modeling tools. Their development and use will be relevant for tackling the current energy issues. The heat transfer models available for the rotary kiln in the literature are, for now, not enough efficient for the baffled-rotary kiln case.The present paper is aimed at suggesting a wall heat transfer correlation for the rotary kilns with the secondary inlet. The experimental thermal data acquired within large-scale rotary drum applied to the asphalt concrete materials production, are remained in order to give rise the new issues. These latter results are connected to a visualization campaign performed at the pilot-scale in order to assess the transversal distribution of the granular phase materials. Their analysis suggests a more appropriate physical modeling of the wall heat transfer path. It leads to transform the classical correlation of type Nu=f(Re,Pr) in a new expression of type Nu=f(Re,St) based on a new physical modeling inventory corresponding to the hot and cold fluxes flowing within the baffled-rotary kiln. Thus, the major modification is based on the introduction of the Stanton (St) number in the wall heat transfer correlation. This expression is found more convenient for the baffled-rotary kiln application. This new expression is validated by the comparison with the experimental Nusselt numbers calculated from the inner heat transfer measurements coefficient measured in the baffled-rotary kiln performed at large scale.

Analyzing the influence of manufacturing conditions of reclaimed asphalt concrete on the characteristics of the asphalt binder: development of a gradual binder extraction method

When asphalt concrete is manufactured incorporating a high percentage (almost 70%) of reclaimed materials from the deconstruction of road surfaces under renovation, and when the corresponding production device is designed specifically to reduce the energy input need (lowering the production temperature), the resulting manufacturing process contributes to the protection of the environment and reduces production costs. However, to meet the quality requirements of the finished product, virgin materials of appropriate quality and quantity must also be added (mineral aggregates and new asphalt binder) and control systems set up to quantify and optimize the parameters involved (thus avoiding the guess work which still often prevails today). It was for this reason that a new experimental technique described here was devised, which will ultimately be used in asphalt concrete production plants. The technique involves lixiviating reclaimed asphalt concrete using a chlorinated solvent; the resulting solute is collected gradually, then the mixture of binders (virgin and reclaimed asphalt concrete) can be characterized and their mass fractions quantified using a combination of UV and IR spectrometry. With this experimental technique we were able to assess the extent to which the reclaimed asphalt pavement binder participates in the agglomeration and cohesion of the reclaimed asphalt concrete. This assessment was made in terms of the main parameters in the production process, temperature of the materials and mixing time.

Determination of the Optimal Polypropylene Fiber Addition to the Dense Bituminous Mixtures by the Aid of Mechanical and Optical Means

Polypropylene fibers are completely native modifiers and they do not have any dependence on abroad in case of technology. When viewed from this point, the modification of bituminous binders with polypropylene fibers is a very important step for our country’s “economical” concerns. In this study, first of all, the physical and chemical effects of polypropylene fibers on bitumen were investigated. Next, the amount of “optimum” polypropylene fibers that has to be added into the mixture was determined. In order to determine it, first, static creep tests and Marshall tests were carried out and then, images of the polypropylene fiber added bituminous binders under fluorescence microscopy were researched. With the application of physical and mechanical tests to the Marshall specimens prepared with the optimum polypropylene amount that was obtained, optimum bitumen content was determined and finally economical analyses were carried out. By carrying out extensive analyses it was seen that the utilisation of polypropylene fibers improves the physical and mechanical properties of the resultant asphalt mixture mainly by enhancing the permanent deformation resistance. On the other hand, polypropylene modification results in 30% economy from bitumen which is a clear indication of the benefit in the mass production of asphalt concrete.