scholarly journals DETERMINATION OF ADHESIVE STRENGTH LAYER’S ROLLER COMPACTED CONCRETE THE METHOD AXIAL EXTENSION

Vestnik MGSU ◽  
2017 ◽  
pp. 647-653
Author(s):  
Van Lam Tang ◽  
Boris Igorevich Bulgakov ◽  
Olga Vladimirovna Aleksandrova
Keyword(s):  
Construction Projects ◽  
Steel Plates ◽  
Roller Compaction ◽  
Fine Aggregate ◽  
Construction Time ◽  
Roller Compacted Concrete ◽  
Axial Tension ◽  
Concrete Layer ◽  
Strength Of Adhesion

Roller compacted concrete for the construction of hydraulic and hydroelectric buildings is a composite material, which consists of a binder, fine aggregate (sand), coarse aggregate (gravel or crushed stone), water and special additives that provide the desired concrete workability and impart the required concrete performance properties. Concrete mixture is prepared at from concrete mixing plants strictly metered quantities of cement, water, additives and graded aggregates, whereupon they are delivered to the site laying Mixer Truck and sealing layers with each stack layer. The advantages of roller compaction technology should include the reduction of construction time, which allows fast commissioning construction projects, as well as reduce the amount of investment required. One of the main problems encountered in the process of roller compaction of the concrete mix is the need to provide the required adhesion strength between layers of concrete. This paper presents a method for determining the strength of adhesion between the concrete layers of different ages roller compacted concrete using axial tension. This method makes it possible to obtain objective and accurate results with a total thickness of layers of compacted concrete of up to 300…400 mm. Results from this method, studies have shown that the value of strength between the concrete layers in addition to the composition of the concrete and adhesion depends on the quality and the parallel end surfaces of the cylinder-models, which are mounted steel plates for axial tension, as well as the state of the contact surfaces of the concrete layer. The method can be used to determine the strength of interlayer adhesion in roller compacted concrete, which are used in the construction of dams and other hydraulic structures.

scholarly journals Classification-Based Regression Models for Prediction of the Mechanical Properties of Roller-Compacted Concrete Pavement

2020 ◽  
Vol 10 (11) ◽  
pp. 3707 ◽  
Author(s):  
Ali Ashrafian ◽  
Mohammad Javad Taheri Amiri ◽  
Parisa Masoumi ◽  
Mahsa Asadi-shiadeh ◽  
Mojtaba Yaghoubi-chenari ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Models ◽  
Mechanical Characteristics ◽  
Concrete Pavement ◽  
Supplementary Cementitious Materials ◽  
Fine Aggregate ◽  
Roller Compacted Concrete ◽  
Interaction Detection ◽  
Model Tree

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential processes for reliable material design and highway sustainability. Early determination of the mechanical characteristics of pavement is essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS), and flexural strength (FS) of roller-compacted concrete pavement (RCCP) are crucial characteristics. In this research, the classification-based regression models random forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p), and chi-square automatic interaction detection (CHAID) are used for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326, and 290 data records for CS, TS, and FS experimental cases was extracted from several open sources in the literature. The mechanical properties are determined based on influential input combinations that are processed using principle component analysis (PCA). The PCA method specifies that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water, and binder) and specimens’ age are the most effective inputs to generate better performance. Several statistical metrics were used to evaluate the proposed classification-based regression models. The RF model revealed an optimistic classification capacity of the CS, TS, and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. Monte-Carlo simulation was used to verify the results in terms of the uncertainty and sensitivity of variables. Overall, the proposed methodology formed a reliable soft computing model that can be implemented for material engineering, construction, and design.

scholarly journals Classification-Based Regression Models for Prediction of Mechanical Properties of Roller Compacted Concrete Pavement

2020 ◽  
Author(s):  
Ali Ashrafian ◽  
Mohammad Javad Taheri Amiri ◽  
Mahsa Asadi-shiadeh ◽  
Isa Yaghoobi-chenari ◽  
Amir Mosavi ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Models ◽  
Mechanical Characteristics ◽  
Concrete Pavement ◽  
Supplementary Cementitious Materials ◽  
Fine Aggregate ◽  
Roller Compacted Concrete ◽  
Interaction Detection ◽  
Model Tree

In the field of pavement engineering, the determination of the mechanical characteristics is one of the essential process for reliable material design and highway sustainability. Early determination of mechanical characteristics of pavement is highly essential for road and highway construction and maintenance. Tensile strength (TS), compressive strength (CS) and flexural strength (FS) of roller compacted concrete pavement (RCCP) are very crucial characteristics as they are necessitated for many data from mixture proportions as input variables. In this research, the classification-based regression models named Random Forest (RF), M5rule model tree (M5rule), M5prime model tree (M5p) and Chi-square Automatic Interaction Detection (CHAID) are developed for simulation of the mechanical characteristics of RCCP. A comprehensive and reliable dataset comprising 621, 326 and 290 data records for CS, TS and FS experimental cases extracted from several open sources over the literature. The mechanical properties are developed based on influential inputs combination that processed using Principle Component Analysis (PCA). The applied PCA method as feature selection is specified that volumetric/weighted content forms of experimental variables (e.g., coarse aggregate, fine aggregate, supplementary cementitious materials, water and binder) and specimens’ age are the most effective inputs to generate the better performances. Several statistical metrics are measured to evaluate proposed classification-based regression models. RF model revealed an optimistic classification capacity of the CS, TS and FS prediction of the RCCP in comparison with the CHAID, M5rule, and M5p models. The research is extended for the results verification using Monte-carlo model for the uncertainty and sensitivity of variables importance analysis. Overall, the proposed methodology indicated a reliable soft computing model that can be implemented for the material engineering construction and design.

DETERMINATION OF THE REMOTION PERCENTAGE OF BARNACLE BIOFOULING FROM MARINE STEEL PLATES USING STEEL BRUSH FOR CLEANING

2021 ◽  
Author(s):  
Rodrigo Guedes ◽  
Vinícius Teles ◽  
Paulo Henrique Vieira Magalhães ◽  
Ana Letícia Pilz de Castro ◽  
Danilo Lisboa ◽  
...  
Keyword(s):  
Steel Plates ◽  
Steel Brush

In Situ Measurement of Poisson’s Ratio of Steel Plates During Thermal Processes Using Resonant Modes

2021 ◽  
Author(s):  
Clemens Grünsteidl ◽  
Christian Kerschbaummayr ◽  
Edgar Scherleitner ◽  
Bernhard Reitinger ◽  
Georg Watzl ◽  
...  
Keyword(s):  
Poisson’S Ratio ◽  
Dual Phase Steel ◽  
Steel Plates ◽  
Poisson's Ratio ◽  
Austenitic Phase ◽  
Resonant Modes ◽  
Longitudinal Sound Velocity ◽  
Contact Free

Abstract We demonstrate the determination of the Poisson’s ratio of steel plates during thermal processing based on contact free laser ultrasound measurements. Our method utilizes resonant elastic waves sustained by the plate, provides high amplitudes, and requires only a moderate detection bandwidth. For the analysis, the thickness of the samples does not need to be known. The trend of the measured Poisson’s ratio reveals a phase transformation in dual-phase steel samples. While previous approaches based on the measurement of the longitudinal sound velocity cannot distinguish between the ferritic and austenitic phase above 770°C, the shown method can. If the thickness of the samples is known, the method also provides both sound velocities of the material. The gained complementary information could be used to analyze phase composition of steel from low temperatures up to its melting point.

Determination of Polymer Type and Content in Concrete Materials by FTIR and TGA

2015 ◽  
Vol 1129 ◽  
pp. 151-158
Author(s):  
Takako Tokura ◽  
Joyce Lim ◽  
Ai Ming Chua ◽  
Wey Liang Lee ◽  
James Wong
Keyword(s):  
Construction Materials ◽  
Attenuated Total Reflection ◽  
Polymer Materials ◽  
Accurate Information ◽  
Fine Aggregate ◽  
Group Information ◽  
Concrete Materials ◽  
Spectrum Matching ◽  
Polymer Type

Polymers are commonly used in concrete materials. The type and concentration of polymer are important information for stakeholders, because they have a critical impact on the properties of concrete materials. Therefore, reliable and accurate information is highly desirable. To this end, Fourier Transform Infrared Spectroscopy (FTIR) and Thermogravimetric Analysis (TGA) are used to analyze polymer contents in construction materials.FTIR spectroscopy is a suitable technique to identify the polymer type using IR spectrum matching. Additionally, functional group information can be easily obtained from each peak. Attenuated Total Reflection (ATR) method can be used to measure extracted polymers from construction materials to obtain IR spectra, and match against the library database to identify the polymer materials. TGA is one of the common thermal analysis methods. It measures the weight loss or gain of sample due to chemical reactions such as vaporization, decomposition and oxidation as a function of temperature. In this paper, we will discuss development of reliable analytical methods with which mixtures of polymer, fine aggregate and cement with different percentages of polymer content were prepared and evaluated.

scholarly journals Delay and cost overrun in road construction projects in Jordan

2015 ◽  
Vol 4 (2) ◽  
pp. 288 ◽  
Author(s):  
Nabil Al-Hazim ◽  
Zaydoun Abusalem
Keyword(s):  
Construction Projects ◽  
Road Construction ◽  
Weather Conditions ◽  
Public Works ◽  
Fiscal Year ◽  
Cost Overrun ◽  
Construction Time ◽  
Change Orders ◽  
Critical Problems ◽  
The Cost

This study aims to identify the most important factors that cause delay in road construction projects in Jordan, which results in cost and time overrun allocated for this type of engineering projects and cause critical problems for both the developer and the contractor. The gap between the cost at completion and that originally estimated, known as cost overrun, can be regarded as one of the most important parameters reflecting the success of projects. In the public sector, money spent on project change orders results in increased construction time which in return reduces the number and size of the projects that can be completed during any given fiscal year. To achieve this goal, the documents and the final reports for several sample projects implemented over the years 2000 to 2008 were analyzed. All the projects were administered by the same organization taken from Jordan Ministry of Rural and Public Works. The results of this study can assist highway officials in their design, planning, scheduling and projects completions so that necessary actions can be taken to control these overruns in future projects. The study showed that 19 factors might cause delays of road construction projects as defined through a detailed literature review. The analysis of the study indicated that the top causes affecting time and cost overrun in road construction projects in Jordan are Terrain and Weather conditions.

Evaluation of Residual Stresses in PVD Coatings by Means of Strip Substrate Length Variation and Curvature Method of Plate Substrate

2017 ◽  
Vol 267 ◽  
pp. 212-218 ◽  
Author(s):  
Harri Lille ◽  
Alexander Ryabchikov ◽  
Jakub Kõo ◽  
Eron Adoberg ◽  
Liina Lind ◽  
...  
Keyword(s):  
Residual Stresses ◽  
Length Change ◽  
Steel Plates ◽  
Length Variation ◽  
Pvd Coatings ◽  
Compressive Stresses ◽  
Steel Strips ◽  
Middle Cross Section ◽  
Method Strip

The aim of the study was to determine macroscopic residual stresses in Physical Vapor Deposits (PVD) coatings through measurement of the length variation of the strip substrates coated on both sides. The length change of the strip was reduced to the deflection of the middle cross-section of the elastic element and was recorded by four strain gauges. For validating the obtained results, the conventional curvature method was used. As an application, residual stresses in hard AlCrN PVD coatings were investigated. The coatings were nanolayered to achieve better coating toughness for blanking and punching applications. The steel strips and steel plates with two thicknesses were used as the substrate. The values of the compressive residual stresses, determined by both methods for the investigated coatings, were very high (3.3 -3.6 GPa) independent of coating thickness and practically equal within the measurement uncertainty of the method. Good agreement between the experimental results obtained with both methods suggests that the presented method, strip length variation, is applicable for determination of residual stresses in coatings. Compressive stresses in coatings are desirable as they strengthen the coating.

scholarly journals A new approach for modelling variability in residential construction projects

2013 ◽  
Vol 13 (2) ◽  
pp. 83-92 ◽  
Author(s):  
Mehrdad Arashpour ◽  
Ron Wakefield ◽  
Nick Blismas ◽  
EWM Lee
Keyword(s):  
Construction Industry ◽  
Construction Projects ◽  
Accurate Determination ◽  
Weather Conditions ◽  
Completion Rates ◽  
New Approach ◽  
Cycle Times ◽  
Product Delivery ◽  
Standard Practices

The construction industry is plagued by long cycle times caused by variability in the supply chain. Variations or undesirable situations are the result of factors such as non-standard practices, work site accidents, inclement weather conditions and faults in design. This paper uses a new approach for modelling variability in construction by linking relative variability indicators to processes. Mass homebuilding sector was chosen as the scope of the analysis because data is readily available. Numerous simulation experiments were designed by varying size of capacity buffers in front of trade contractors, availability of trade contractors, and level of variability in homebuilding processes. The measurements were shown to lead to an accurate determination of relationships between these factors and production parameters. The variability indicator was found to dramatically affect the tangible performance measures such as home completion rates. This study provides for future analysis of the production homebuilding sector, which may lead to improvements in performance and a faster product delivery to homebuyers. 

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