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.

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.

Mechanical Properties of Hydroxyapatite Doped with Magnesium, Used in Bone Implants

2013 ◽  
Vol 430 ◽  
pp. 222-229 ◽  
Author(s):  
Oana Suciu ◽  
Teodora Ioanovici ◽  
Liviu Bereteu
Keyword(s):  
Mechanical Properties ◽  
Thermal Stability ◽  
Modulus Of Elasticity ◽  
Mechanical Characteristics ◽  
Precipitation Method ◽  
Bone Implants ◽  
Wet Precipitation ◽  
Longitudinal Modulus

Hydroxyapatite is a biomaterial, more exactly a bioceramic, from a category of materials frequently used in bone implants. In order to improve mechanical properties, hydroxyapatite is doped with different chemical substitutes, among which the most used are: Mg2*, Zn 2*, La3*, Y3*, In3* Bi3* CO32-, Si and Mn. In the paper are presented the modality of obtaining hydroxyapatite doped with magnesium through wet precipitation method and also the determination of its main mechanical characteristics. There is also an analysis on the effects of magnesium on the following mechanical properties: density, hardness, longitudinal modulus of elasticity, conductibility and thermal stability.

scholarly journals Determination of Mechanical Properties of Rubberized Concrete in Marine Environment

2019 ◽  
Vol 8 (2) ◽  
pp. 5761-5765
Keyword(s):  
Mechanical Properties ◽  
Fly Ash ◽  
Marine Environment ◽  
Concrete Specimen ◽  
Crumb Rubber ◽  
Fine Aggregate ◽  
Test Results ◽  
Rubberized Concrete ◽  
Split Tensile Strength

With an objective of saving the environment by providing crumb rubber as an alternative to natural fine aggregate this paper presents a study carried out to find the mechanical properties of rubberized concrete. Rubberized concrete is made up of waste rubber from vehicle tyres and other rubber waste which otherwise is left out polluting the environment. In this paper, 7.5% of crumb rubber (obtained by shredding the vehicle tyres) as an alternative to fine aggregate and 7.5% of fly-ash as an alternative to cement is added with other ingredients of concrete to produce an eco-friendly concrete which can be used economically and effectively for construction along the coastal areas. Various properties like workability, compressive strength, split tensile strength, and flexural strength was carried out on concrete specimens exposed to the natural marine environment along the coast of Visakhapatnam, Andhra Pradesh. The total exposure of concrete specimen was about 150 days, and various specimens were tested at 7, 28, 90, 120 and 150 days, respectively. The test results showed that with a slight compromise in strength, the workability of concrete and resistance to the effect of seawater on the strength of concrete significantly improved with the addition of crumb rubber and fly-ash.

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.

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