scholarly journals OBTAINING A THERMAL INSULATION LAYER FROM MONOLITHIC NON-AUTOCLAVED STRUCTURAL AND THERMAL INSULATION FIBRE FOAM CONCRETE

2021 ◽  
Vol 4 (3) ◽  
pp. 5-22
Author(s):  
S. Plehanova ◽  
N. Vingradova
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Road Surface ◽  
Cement Stone ◽  
Insulation Layer ◽  
Foam Concrete ◽  
Joint Work ◽  
The Road ◽  
Road Pavement ◽  
Reinforced Cement

the possibility of obtaining structural and thermal insulation foam concrete of non-autoclave hardening with improved construction and technical characteristics for the device of a thermal insulation layer in the con-struction of road pavement due to three-dimensional dispersed reinforcement with polypropylene fiber is theoretically justified and experimentally confirmed. Based on the results of studies of the influence of technological factors on the properties of foam concrete, the optimal content (up to 0.25% of the cement mass) and the length (12 mm) of reinforcing polypropylene fibers have been established, which allows ob-taining high strength indicators of dispersed-reinforced cement stone for bending (an increase of 12-20%) and compression (an increase of 6-12%) compared with non-reinforced cement stone of non-autoclaved foam concrete. The analysis of the process of structure formation of dispersed reinforced foam concrete from the standpoint of a systematic approach based on multifactorial polynomial models of the influence of the ratio of filler and binder, as well as the number of dispersed reinforcing fibers, which is determined by the optimal conditions for the distribution of solid and gas phases, as well as the reinforcement of adjacent interstitial partitions of foam concrete, linking them into one asociate, which ensures the joint work of the material under various external influences. A method was developed to increase the durability of the road surface and eliminate the influence of the frost heaving effect on the quality of the road surface by intro-ducing the necessary amount of effective thermal insulation layer into the road surface design. The analysis of the regularity of the heat transfer process in the soil mass of the roadbed and multilayer road pavement is carried out. Based on the analysis, the values of the necessary resistance to heat transfer of road pavement for the natural and climatic regions of the country are determined and a method for calculating the value of the thermal insulation (frost-proof) layer of road pavement is proposed. A method was developed for calcu-lating the value of the thermal insulation layer using monolithic fibre foam concrete and a nomogram to de-termine the required value of the thermal insulation layer made of monolithic non-autoclaved structural and thermal insulation fibre foam concrete of classes D600-D1000.

Analysis of Heat Loss of Ground Pipeline of Thermal Production Oilfield

2011 ◽  
Vol 90-93 ◽  
pp. 3057-3060 ◽  
Author(s):  
Jian Jun Liu ◽  
Gui Hong Pei ◽  
You Jun Ji
Keyword(s):  
Heat Transfer ◽  
Layer Thickness ◽  
Heat Loss ◽  
Thermal Insulation ◽  
Oil Recovery ◽  
Heavy Oil ◽  
Insulation Layer ◽  
Obvious Effect ◽  
Steam Pipeline ◽  
Heat Transfer Theory

Steam stimulation is one of the main methods used in heavy oil reservoir development. How to inject high temperature and high dryness steam is a key factor to enhance heavy oil recovery. It is significant to evaluate heat transfer of steam pipeline and optimize thermal insulation layer for heavy oil exploitation. Based on fluid mechanics, heat transfer theory, considered phase change, mathematical model to calculate heat transfer and heat loss of steam pipeline was derived. Using COMSOL Multiphysics, a finite element based program for simulating unlimited multiphysics and single physics applications, the author simulated heat transferring in ground steam pipeline and analyzed the effect of thermal insulation layer. From the simulation results, it was known that, (1) Along with the pipeline distance increases, the steam dryness decreases, the decrease rate decreases with the distance increases. (2) At the same transmission distance, the bigger the thermal insulation layer thickness is, the smaller the heat loss of the steam is. The heat loss of steam transmission mainly center on the first half pipeline. (3) With the thickness of thermal insulation layer increases, the heatloss declines. After the thickness of thermal insulation layer increases 90 mm, increasing the thickness has no obvious effect on reducing the heat loss. So, it is suggested that the thermal insulation layer thickness should be 75-80mm.

scholarly journals TINJAUAN KONDISI PERKERASAN JALAN DENGAN KOMBINASI NILAI INTERNATIONAL ROUGHNESS INDEX (IRI) DAN SURFACE DISTRESS INDEX (SDI) PADA JALAN TAKENGON – BLANGKEJEREN

2018 ◽  
Vol 1 (3) ◽  
pp. 543-552
Author(s):  
Baihaqi Baihaqi ◽  
Sofyan M. Saleh ◽  
Renni Anggraini
Keyword(s):  
Road Surface ◽  
Road Segment ◽  
International Roughness Index ◽  
Damage Level ◽  
The Road ◽  
Road Pavement ◽  
Roughness Index ◽  
Surface Distress ◽  
Observation Method ◽  
Pavement Damage

Abstract: Takengon - Blangkejeren road is one of the cross national roads connecting Central Aceh Regency with Gayo Lues Regency. This road is in the mountainous terrain and often passed by heavy loaded vehicles so that often damaged. To overcome the frequent damage to this road segment, it is necessary to conduct a research on road pavement damage. The purpose of this research is to know the condition of road damage based on the combination of International Roughness Index (IRI) and Surface Distress Index (SDI). This study uses direct observation method in the field by conducting a visual survey of road pavement conditions. The result of the research shows that the total damage level of road surface is 30,54% while the road surface is not damaged by 69,46% from total of road that become research object, that is 12,63 Km divided into 6 road segment. For the overall condition of roads reviewed 45.02% good, 45.81% medium, 6.87% lightly damaged, 2.29% heavily damaged.Abstrak: Ruas jalan Takengon – Blangkejeren merupakan salah satu ruas jalan nasional lintas tengah yang menghubungkan Kabupaten Aceh Tengah dengan Kabupaten Gayo Lues. Jalan ini berada pada medan pegunungan dan sering dilalui kendaraan dengan beban yang berat sehingga sering mengalami kerusakan. Untuk mengatasi kerusakan yang sering terjadi pada ruas jalan ini perlu diadakan suatu penelitian mengenai jenis kerusakan perkerasan jalan. Tujuan dari penelitian ini adalah untuk mengetahui kondisi kerusakan jalan berdasarkan kombinasi nilai International Roughness Index (IRI) dan Surface Distress Index (SDI). Penelitian ini menggunakan metode pengamatan langsung dilapangan dengan melakukan survey secara visual terhadap kondisi perkerasan jalan. Dari hasil penelitian diperoleh tingkat kerusakan keseluruhan permukaan jalan adalah sebesar 30,54% sedangkan permukaan jalan yang tidak mengalami kerusakan sebesar 69,46 % dari total panjang jalan yang menjadi objek penelitian, yaitu 12,63 Km yang dibagi menjadi 6 buah segmen jalan. Untuk kondisi keseluruhan jalan yang ditinjau 45,02 % baik, 45,81 % sedang, 6,87 % rusak ringan, 2,29 % rusak berat.

scholarly journals Non-autoclaved foam concrete for layers of highways surface dressing

2020 ◽  
Vol 2020 (2) ◽  
pp. 35-41
Author(s):  
Iryna Hornikovska ◽  
◽  
Vadym Kahanov ◽  
Keyword(s):  
Operating Cost ◽  
Road Construction ◽  
Road Surface ◽  
Transport Infrastructure ◽  
Foam Concrete ◽  
Insulating Material ◽  
The Road ◽  
Effective Heat ◽  
Geographical Regions ◽  
Pavement Structure

The article is devoted to the problems associated freeze with the calculated estimation of the parameters of the structural and heat-insulating antifreeze layer in the subgrade of non-rigid roads on various soil bases. The main physical, technical and deformation characteristics of monolithic dispersed non-autoclaved foam concrete reinforced with polypropylene fiber of grades of density from 600 to 1000 kg/m3 are investigated. Freezing of subsoil waters directly under the roadway pavement and, as a result, its increase in volume, leads to significant deformations of the road surface. Under such conditions, the period of defectfree operation of the roadway pavement is significantly reduced, which in turn leads to the need to repair it in a more intensive mode. One of the ways to reduce the operating cost and maintenance costs of the road transport infrastructure is to introduce into the design and construction practice new structural concepts for road surface dressing that ensure high quality pavement during the normative operational period. This can be achieved by introducing an effective heat-insulating material into the pavement structure as an anti-frost layer in order to elimi-nate the effect of frost lift of the roadway pavement of non-rigid roads. Since domestic and foreign experience freeze in the road construction has proven the effectiveness of the use of heatinsulating materials in the road surface dressing construction, in recent years in Ukraine there has been increased interest in the use of non-autoclaved foam concrete as a modern and highly effective heat-insulating material in road construction. The installation of a heat-insulating layer made of non-autoclaved foam concrete allows us to completely or partially prevent freezing or overheating of the surface dressing base, reduce the influence of periodic variations in environmental temperature, which in turn will increase the durability of the pavement structure. The publication presents nomograms for determining the optimal thickness of the heat-insulating anti-frost heavy course (layer) of road surface dressing (based on sand, loamy sand, clay and loam) done at the street and road network for all climatic and geographical regions of Ukraine.

scholarly journals Heat transfer analysis of surrounding rocks with thermal insulation layer in high geothermal roadway

2017 ◽  
pp. 178-178
Author(s):  
Yuan Zhang ◽  
Zhijun Wan ◽  
Zhaoyang Ma ◽  
Bin Gu ◽  
Yangsheng Ma
Keyword(s):  
Heat Transfer ◽  
Thermal Insulation ◽  
Heat Transfer Analysis ◽  
Insulation Layer

Toward Using Tire-Road Contact Stresses in Pavement Design and Analysis

2012 ◽  
Vol 40 (4) ◽  
pp. 246-271 ◽  
Author(s):  
Morris De Beer ◽  
James W. Maina ◽  
Yvette van Rensburg ◽  
Jan M. Greben
Keyword(s):  
Contact Stress ◽  
Contact Stresses ◽  
Road Surface ◽  
Pavement Design ◽  
Tire Model ◽  
Contact Patch ◽  
Circular Shape ◽  
The Road ◽  
Road Pavement ◽  
Vertical Contact

ABSTRACT: Optimization of road pavement design, especially close to the surface of the pavement, requires a more rational approach, which will inevitably include modeling of truck tire-road contact stresses. Various road-surfacing failures have been recorded as evidence that the traditional road pavement engineering tire model idealized by a single uniformly distributed vertical contact stress of circular shape may be inadequate to properly explain and assist in the design against road surface failures. This article therefore discusses the direct measurement of three-dimensional (3D) tire pavement contact stresses using a flatbed sensor system referred to as the “Stress-In-Motion” (SIM) system. The SIM system (or device) consists of multiple conically shaped steel pins, as well as an array of instrumented sensors based on strain gauge technology. The test surface is textured with skid resistance approaching that of a dry asphalt layer. Full-scale truck tires have been tested since the mid-1990s, and results show that 3D tire contact stresses are nonuniform and that the footprint is often not of circular shape. It was found that especially the vertical shape of contact stress distribution changes, mainly as a function of tire loading and associated tire inflation pressures. In overloaded/underinflated cases, vertical contact stresses are the highest toward the edges of the tire contact patch. Higher inflation pressures at lower loads, on the other hand, result in maximum vertical stresses toward the center portion of the tire contact patch. These differences in shape and magnitude need to be incorporated into modern mechanistic-empirical road pavement design tools. Four different idealized tire models were used to represent a single tire type to demonstrate effects of tire modeling on the road pavement response of a typical South African pavement structure incorporating a relatively thin asphalt surfacing. Only applied vertical stress was used for the analyses. It was found that the fatigue life of the road surface layer can be reduced by as much as 94% and strain energy of distortion be increased by a factor of 2.8, depending on the characteristics of the tire model input selected for road pavement design and analysis.

Investigation of the Effect of Reducing the Thickness of Road Surfacing Layers Within the Tolerance Limits on the Reliability and Durability of Highways

2020 ◽  
pp. 43-57
Author(s):  
С. В. Гошовец
Keyword(s):  
Surface Structure ◽  
Layer Thickness ◽  
Negative Impact ◽  
Road Surface ◽  
Tolerance Limits ◽  
Surface Layers ◽  
Design Standards ◽  
Strength Criteria ◽  
The Road ◽  
Road Pavement

Состояние проблемы. Считается, что уменьшение толщины слоя в пределах допуска не оказывает существенного влияния на надежность и долговечность дорожной одежды. Так как конструкция дорожной одежды, как правило, состоит из нескольких слоев, можно предположить, что занижение толщины слоев в пределах допуска может оказать негативное влияние на прочность конструкции в целом. Применительно к отечественным нормам проектирования и строительства данное предположение остается не изученным. Результаты. Проведен анализ показателей, характеризующих толщину слоя, и практик назначения строительных допусков. Проанализированы исследования влияния допуска на надежность дорожной одежды и рекомендации по корректировке толщины слоев конструкции под влиянием допусков. Выполнены моделирование и расчет конструкций с учетом допусков. Выводы. Полученные результаты подтвердили предположение о том, что уменьшение толщины слоев дорожной одежды в пределах допусков негативно влияет на все критерии прочности. Предложено решение по устранению несогласованности между строительными допусками и нормами проектирования. Statement of the problem. Reducing the layer thickness within the tolerance is considered not to have a significant effect on the reliability and durability of the road surface structure. Since the construction of roadways usually consists of several layers, the assumption that understating the thickness of the layers within the tolerance can have a negative impact on the overall strength of the structure is not unreasonable. In relation to the domestic standards for the design and construction of this assumption has not yet been studied. Results. The analysis of indicators characterizing the layer thickness and practices for the purpose of construction tolerances, analysis of recommendations in the design standards for correcting the thickness of the layers of the structure due to the influence of tolerances, studies of the influence of tolerance on the reliability of road pavement, modeling and calculation of structures with allowances, suggestions are provided. Conclusions. The results confirmed the assumption that reducing the thickness of road surface layers within the tolerance limits negatively affects all the strength criteria. We have proposed a solution in order to eliminate inconsistencies between construction tolerances and design standards.

Justification Constructions of the Road Pavement Under Conditions of Changing Road Surface Temperature

2021 ◽  
pp. 161-172
Author(s):  
Anatoly Novik ◽  
Igor Drozdetskiy ◽  
Pavel Petukhov ◽  
Nikita Labusov ◽  
Vasilina Novik ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Road Surface ◽  
The Road ◽  
Road Pavement ◽  
Road Surface Temperature

scholarly journals INVESTIGATION INTO THE STABILITY OF DRIVING AN AUTOMOBILE ON THE ROAD PAVEMENT WITH RUTS

Transport ◽  
2009 ◽  
Vol 24 (2) ◽  
pp. 170-179 ◽  
Author(s):  
Vidmantas Vansauskas ◽  
Marijonas Bogdevičius
Keyword(s):  
Mathematical Model ◽  
Mathematical Simulation ◽  
Road Safety ◽  
Road Surface ◽  
First Line ◽  
The Road ◽  
Road Pavement ◽  
On The Road ◽  
The Stability

The article reviews the stability of an automobile on the road pavement with ruts. The problems of road safety depend on many factors. One of those is the quality of the road surface. Big heavy lorries deform the road surface causing ruts especially in the first line of the road. The article analyzes the influence of the geometry of ruts on the stability of the automobile. A mathematical model of a 3D automobile and the interaction between wheels and the road surface and the geometry of the road surface are presented. The mathematical criterion of the stability of the moving automobile on the road surface with ruts is laid down. The results of mathematical simulation and the criterion of the stability of the moving automobile (60 km/h) on the road surface depending on the depth of ruts are introduced.

scholarly journals PHOTOGRAMMETRIC TECHNIQUES FOR ROAD SURFACE ANALYSIS

2016 ◽  
Vol XLI-B5 ◽  
pp. 515-520 ◽  
Author(s):  
V. A. Knyaz ◽  
A. G. Chibunichev
Keyword(s):  
Surface Analysis ◽  
Surface Reconstruction ◽  
Measuring Method ◽  
Parameters Estimation ◽  
Road Surface ◽  
The Road ◽  
Road Pavement ◽  
Powerful Means ◽  
Aerial Vehicle ◽  
Road Materials

The quality and condition of a road surface is of great importance for convenience and safety of driving. So the investigations of the behaviour of road materials in laboratory conditions and monitoring of existing roads are widely fulfilled for controlling a geometric parameters and detecting defects in the road surface. Photogrammetry as accurate non-contact measuring method provides powerful means for solving different tasks in road surface reconstruction and analysis. The range of dimensions concerned in road surface analysis can have great variation from tenths of millimetre to hundreds meters and more. So a set of techniques is needed to meet all requirements of road parameters estimation. Two photogrammetric techniques for road surface analysis are presented: for accurate measuring of road pavement and for road surface reconstruction based on imagery obtained from unmanned aerial vehicle. The first technique uses photogrammetric system based on structured light for fast and accurate surface 3D reconstruction and it allows analysing the characteristics of road texture and monitoring the pavement behaviour. The second technique provides dense 3D model road suitable for road macro parameters estimation.

Sign in / Sign up

Export Citation Format

Share Document