Improvement of crushed stone – mastic asphalt laying by improving of the conditions of its transportation

2021 ◽  
Vol 2021 ◽  
pp. 139-143
Author(s):  
Denis Shpin ◽  

Introduction. Transport times of hot asphalt from its production facility to the road section of laying depends of the distance of the asphalt mixing plants location, also in urban conditions it depends from the intensity of traffic flows, the number of traffic jams on the way of the dump truck.Problems. At the present stage, a sharp decrease of road pavement quality and durability occurs due to an increase of the number of heavy vehicles, an increase of axle loads on the pavement and an increase in the speed limit, due to use of outdated technologies that not correspond to the existing loads by their technical characteristics.Purpose. To analyze the modern technology of crushed stone — mastic asphalt transportation in order to determine the shortcomings in its application.Materials and methods. Analysis of information sources, including foreign sources regarding transportation technologiesResults.Possible consequences of non-observance of the correct transportation technology and their elimination have been determined.Conclusions. During the transportation of crushed stone — mastic asphalt mixture, the temperature and fractional segregation (dissection) of the hot mixture occurs. The main factors that cause it are following: ambient temperature, air humidity, wind speed, bulk filling, transport times, pavement flatness during transportation. To prevent the segregation appearance, it is need to increase the loading rate of the dump truck bulk, using heat-insulating elements during transportation (awnings, metal covers, etc.), also as thorough cleaning of the dump truck bulk surface from any residuals of bituminous and other materials before each loading of crushed stone-mastic asphalt.Keywords: crushed stone-mastic asphalt, temperature segregation, transportation technology.

2020 ◽  
Vol 15 (3) ◽  
pp. 157-168
Author(s):  
Lina Šneideraitienė ◽  
Daiva Žilionienė

The quality of the paved road depends not only on the decisions of the road designer and the work carried out but also on the materials used. Most of the aggregates used are imported from other countries. However, the usage of domestic materials reduces the cost of the road pavement and the use of aggregates produced by a special production technology in Lithuania, i.e., dolomite aggregates instead of granite aggregates. Experimental studies were carried out on the skid resistance of the road surface. It was found that the coefficient of skid resistance met the requirements for surface dressing with dolomite aggregate, and the results were analysed with 95% probability. This coefficient partially met the requirements for asphalt concrete, while it did not meet the requirements at all for stone mastic asphalt. The surface roughness, however, met the requirements for road sections where granite aggregates were used instead of dolomite in mixes of surface dressing and asphalt concrete. The analysis was carried out considering the volume of traffic and the service life of the individual road sections. It was determined that it was suitable for a 5-year guarantee period to perform the surface dressing, wearing course of asphalt concrete and stone mastic asphalt with dolomite aggregate where part of heavy vehicles is less than 20% of traffic flow. The use of granite aggregates was justified only in the road where heavy vehicles dominated.


Author(s):  
D. A. Yastremsky ◽  
T. N. Abaydullina ◽  
A. I. Kudyakov

High-quality and durable asphalt pavement ensures safe and comfortable traffic, optimal logistics costs, territory attractiveness to construction investments, and industrial development. With constantly increasing loads on road pavements, it is necessary to improve the asphalt quality by introducing additives into the mixture, design methodology, scientific justification for the selection and preparation of raw materials. The paper proposes the development algorithm of crushed-stone and mastic asphalt modified by the new stabilizing additive, which consists of 90 % of cellulose fiber from waste paper, 5 % rubber powder, and 5 % bitumen. The optimal particle size distribution of the mineral component in the crushed-stone and mastic asphalt is considered to be 73% of crushed stone with fractions of 15–20, 10–15 and 5–10 mm, 16 % of dolomite sand from crushing screenings, 11 % of mineral powder, 0.4 % of stabilizing additive and 5.5 % of bitumen. The compressive strength of the developed composition is 2.3 times higher than that meeting the requirements of GOST 31015–2002 for the climatic zone II. The research results are confirmed by pilot-industrial tests in constructing the road pavement in Tyumen.


Author(s):  
S. Navolokina ◽  
V. Yadykina ◽  
Anatoliy Gridchin

Heavy traffic reduces the strength characteristics of asphalt concrete, causes peeling on the pavement. Crushed stone-mastic asphalt concrete is designed for the device of the upper layers of the coating on roads with high traffic intensity. The use of polymerasfalt concrete on a modified binder can lead to an improvement in the physical and mechanical characteristics of asphalt concrete and increase its re-sistance to climatic influences. The main aspects of improving the quality of crushed stone-mastic as-phalt concrete (SMA) due to the use of a binder modified with sevilen (SEVA) are discussed. The effect of bitumen containing sevilen with 22 and 29 % vinyl acetate groups on the properties of crushed stone-mastic asphalt concrete has been investigated. Analysis of the results showes that the use of modified binders has a positive effect on the entire complex of physical and mechanical parameters of polymer asphalt concrete. An increase in the strength of the samples at 20 and 50 °C, a decrease in this indicator at 0 °C is established. The indicators of water and heat resistance, shear resistance and crack resistance are also improved, which should have a positive effect on the durability of the road surface. Rational concentrations of polymer additives and the amount of vinyl acetate groups in its composition have been established. The adhesion of the binder to the mineral part of the asphalt con-crete mixture is estimated. The index of sensitivity to temperature differences of asphalt concrete sam-ples is considered due to the fact that asphalt concrete is a material that reacts to temperature fluctua-tions in the external environment. The analysis of the results of the tests carried out demonstrates that the use of modified binders has a positive effect on the entire complex of physical and mechanical pa-rameters of polymer asphalt concrete.


Author(s):  
Ekarizan Shaffie ◽  
◽  
H.A. Rashid ◽  
Fiona Shiong ◽  
Ahmad Kamil Arshad ◽  
...  

Stone Mastic Asphalt (SMA) is a gap-graded hot mixture designed to provide higher resistance towards permanent deformation and rutting potential by 30% to 40% more than dense-graded asphalt, due to its stable aggregate skeleton structure. However, compared to other types of hot mix asphalt, SMA unfortunately has some shortcomings in term of its susceptibility towards moisture-induced damage due to its structure and excessive bitumen content in the composition. This research aims to assess the performance of a SMA mixture with steel fiber by enhancing overall stability, abrasion resistance, and, most importantly, moisture susceptibility. This study involved the incorporation of various steel fiber proportions of 0%, 0.3%, 0.5% and 0.7% by the total weight of mixture. The steel fiber modified SMA was made up of 6.0% PEN 60/70 bitumen content. The performance of SMA were evaluated through Marshall stability and flow test, Cantabro loss test and indirect tensile strength test. The results obtained from the testing showed that the incorporation of steel fiber is significantly effective to enhance the resistance towards moisture damage, while increasing the stability and reducing the abrasion loss of SMA mixture, compared to conventional mixture. Overall, it can be concluded that the addition of steel fiber in asphalt mixture specifically SMA, has improved the mechanical performance in the application of asphalt pavement with the optimum steel fiber proportion of 0.3% by the weight of mixture. The developed models between the independent variables and responses demonstrated high levels of correlation. The study found that Response Surface Methodology (RSM) is an effective statistical method for providing an appropriate empirical model for relating parameters and predicting the optimum performance of an asphaltic mixture to reduce flexible pavement failure.


Author(s):  
A. Kurlykina ◽  
V. Denisov ◽  
D. Kuznecov ◽  
E. Lukash

One of the main reasons for reducing the service life of road asphalt pavements (the appearance and development of damage in the form of ruts, various kinds of plastic deformations, potholes, cracks, etc.) is the low quality of the used oil bitumen. The physicomechanical properties of road bitumen are subject to stricter requirements, especially for organic binders used for the production of crushed stone mastic asphalt (SMA), therefore, in authors’ view, the development of bitumen binders with enhanced physicomechanical properties is one of the key and most urgent tasks in road construction. This problem is solved by introducing various modifiers into the binder. This article presents the results of a study of bitumen modified by introducing technical sulfur into the composition. The effect of binder modification on the physicomechanical properties of road asphalt concrete is shown on the example of crushed stone mastic asphalt (SMA-20) relative to base samples made to control the dynamics of changes in the properties of composites made using sulfur-raising technologies. For a comprehensive assessment of the effectiveness of modifying crushed stone mastic asphalt concrete based on various binders, a generalized quality criterion is calculated, taking into account the calculated particular quality criteria and various values of the weight coefficients. The comparison and analysis of the obtained efficiency criteria is made.


2014 ◽  
Vol 505-506 ◽  
pp. 204-209
Author(s):  
Biao Ding ◽  
Chuan Chao Zheng ◽  
Hua Nan Wang

Conventional fatigue damage test of asphalt mixture is usually under the condition of constant stress-mode or strain-mode, the specimen is broken when the cyclic load reaches certain number of times. In fact, vehicles on the road are not continuous, traffic volume is different in different time, there is a time interval between neighbouring vehicles. In this paper, time interval was set between two neighbouring cycles, the effect of recovery way, strain size and temperature on cumulative dissipated energy were analyzed. The results show that: in the early stages, recovery methods have little impact on the cumulative dissipated energy, with the increase of cyclic number, the value of trabecular under unconstrained condition will be greater than that of trabecular under constrained one. The bigger the strain size, the greater the value of cumulative dissipated energy; The lower the temperature, the greater the value of cumulative dissipated energy. Under the conditon of low strain size or high temperature , the value of cumulative dissipated energy decreases linearly. For the high strain or low temperature, there is a sharp decrease between the first cycle and second cycle, and then decreases linely in the later cylcles.


2020 ◽  
Vol 992 ◽  
pp. 200-205
Author(s):  
S.Yu. Shekhovtsova

Stone mastic asphalt concrete is one of the main types of asphalt concrete used for the construction of road surfaces. The quality, reliability and longevity of which depends on road safety of vehicles. To reduce the intensity of aging processes occurring at the stage of production and laying of asphalt concrete, "green" technologies are used, based on the use of physical and chemical processes that reduce the viscosity of bitumen to produce warm asphalt mixtures. This paper discusses the features of the formation of properties of crushed stone-mastic asphalt mixes SMA-15 based on polymer bitumen modified, compacted at lower temperatures, relative to traditional asphalt concrete. The influence of chemical additives of domestic and foreign production of DAD-TA and Cecabase RT 945 on the properties of modified binder and asphalt concrete was studied. It was established that they have a positive plasticizing effect on the modified bitumen binder in crushed stone-mastic asphalt concrete without a decrease in heat resistance and adhesive strength, which made it possible to compact asphalt concrete samples at low temperatures (up to 130°C) without negatively affecting the strength and deforming properties of asphalt concrete.


2018 ◽  
Vol 45 ◽  
pp. 00114
Author(s):  
Lesław Bichajło ◽  
Krzysztof Kołodziej

The paper characterizes the porous asphalt mixture used in pavement construction. This kind of pavement can reduce traffic noise and reduce the slipperiness of the road pavement. The effectiveness of the porous asphalt depends on many design and technological aspects, but especially on the air-void clearance in the pavement layer. The paper includes the results of water permeability research based on laboratory tests of specimens from actual road pavement. The research shows the differences between the contamination of the road pavement sections located inside and outside the city. The paper includes recommendations for using porous asphalt based on experiences under Polish conditions.


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