Wyniki wyszukiwania dla: CONSTRUCTION - MOST Wiedzy

The paper presents a current study devoted to the optimization of the amount of PCM present within traditional building materials, utilized in this case in hollow-brick walls. Authors focus on proposing an alternative to typical direct addition of PCM to existing building materials: introducing two- and three-component mixtures, based on a porous PCM carrier, which in this case was construction aggregate. Preliminary studies of...

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An experimental study of self-sensing concrete enhanced with multi-wall carbon nanotubes in wedge splitting test and DIC

Publikacja

J. Suchorzewski
M. Prieto
U. Mueller

Concrete is the worldwide most utilized construction material because of its very good performance, forming ability, long-term durability, and low costs. Concrete is a brittle material prone to cracking. Extensive cracking may impact durability and performance over time considerably. The addition of a small amount of carbon nanotubes (CNT) increases the concrete’s overall electrical conductivity, enabling internal structure...

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Prediction of cast-in-place concrete strength of the extradosed bridge deck based on temperature monitoring and numerical simulations

Publikacja

The work is devoted to the implementation of a monitoring system for high performance concrete embedded in the span of an extradosed bridge deck using a modified maturity method augmented by numerical simulations conducted by the authors’ FEM code. The paper presents all research stages of bridge construction and considers the conclusions drawn from the results of laboratory tests, field measurements, and numerical calculations....

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Simple empirical formula to estimate the main geomechanical parameters of preplaced aggregate concrete and conventional concrete

Publikacja

A. M. Rajabi
F. Omidi Moaf

Preplaced aggregate concrete (PAC) or two-stage concrete is a specific type of concrete successfully employed in many projects including underwater concrete structures, massive concrete structures, structures made of reinforced concrete, and improvement of concrete structures. PAC is significantly different than the conventional concrete. In this type of concrete, aggregates are initially poured into the mold, the voids between...

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The long-term properties of mineral-cement-emulsion mixtures

Publikacja

This publication presents evaluation of long-term behavior of mineral-cement-emulsion (MCE) mixtures. MCE mixtures are among the major products of cold recycling of old asphalt pavements. They are composed by binding of the old materials reclaimed from the pavement and new mineral aggregate using two different binding agents – cement and bituminous emulsion. While bituminous emulsion dissolutes and binds materials quite fast, it...

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Fire-induced spalling of ultra-high performance concrete: A systematic critical review

Publikacja

M. Amran
G. Murali
M. Kurpińska
M. L. Nehdi

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2023

Ultra-high performance concrete (UHPC) is a novel concrete class characterized by a compressive strength of more than 150 MPa. One of the most significant drawbacks of employing UHPC is that is very low permeability owing to its great compactness of dense structure increases the risk of fire-induced spalling. It is challenging for fire safety and structural engineers to predict and analyze this issue due to the lack of widely accepted...

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Application and modelling of Shape-Memory Alloys for structural vibration control: State-of-the-art review

Publikacja

A. Tabrizikahou
E. Noroozinejad
S. Li
P. Gardoni
M. Noori
M. Kuczma
M. Łasecka-Plura

- Construction and Building Materials - Rok 2022

One of the most essential components of structural design for civil engineers is to build a system that is resistant to environmental conditions such as harsh chemical environments, and catastrophic disasters like earthquakes and hurricanes. Under these circumstances and disturbances, conventional building materials such as steel and concrete may demonstrate inadequate performance in the form of corrosion, deterioration, oxidizing,...

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Current trends in the field of steganalysis and guidelines for constructions of new steganalysis schemes

Publikacja

B. Czaplewski

- Przegląd Telekomunikacyjny + Wiadomości Telekomunikacyjne - Rok 2017

The paper concerns blind steganalysis techniques in the passive steganalysis scenario designed to detect the steganographic cover modification schemes. The goal is to investigate the state-of-art in the field of steganalysis, and, above all, to recognize current trends existing in this field and determine guidelines for constructions of new steganalysis schemes. The intended effects are to examine the possibilities for the development...

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Detection of stray current field interference on metal constructions using STFT

Publikacja

- Rok 2005

Zaprezentowano metodę detekcji pola prądów błądzących wykorzystującą krótkoczasową transformatę Fouriera STFT. Ten sposób analizy umożliwia wyznaczenie zmian spektralnej gęstości mocy sygnału (np. potencjału konstrukcji) w funkcji czasu. Przedstawiono rezultaty analizy zmian potencjału w polu prądów błądzących generowanych przez trakcję tramwajową. Spektrogramy są kompozycją prążków w łącznej dziedzinie czasu i częstotliwości....

A time-frequency method for detection of electromagnetic field interference on metal constructions.

Publikacja

K. Żakowski

- Rok 2004

Przedstawiono metodę detekcji oddziaływania pola elektromagnetycznego na metalowe konstrukcje podziemne. Polega ona na czasowo-częstotliwościowej analizie rejestrów zmian potencjału źródła pola (np. prądów błądzących) oraz potencjału konstrukcji podziemnej, z wykorzystaniem krótkoczasowej transformaty Fouriera STFT. Wnioski o oddziaływaniu pola na konstrukcję metalową wyciąga się na podstawie analizy uzyskanych widm.

Mechanical properties of Precontraint 1202S coated fabric under biaxial tensile test with different load ratios

Publikacja

A. Ambroziak

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2015

The paper describes a method of laboratory tests necessary for identifying the mechanical properties of polyester coated fabrics named Precontraint 1202S with PVDF surface treatment. Two sets of initial material parameters for dense net model and orthotropic model are specified. Material parameters for Precontraint 1202S coated fabric are specified on the basis of the biaxial tensile tests for different load ratios. In order to...

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Assessment of microstructure, physical and thermal properties of bitumen modified with LDPE/GTR/elastomer ternary blends

Publikacja

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2016

LDPE/GTR/elastomer ternary blends with variable LDPE/GTR ratio and constant elastomer content were prepared via melt-compounding. Obtained LDPE/GTR/elastomer blends were applied as thermoplastic modifiers into bitumen. Microstructure, physical and thermal properties of the modified bitumen were determined. It was observed that chemical composition of LDPE/GTR/elastomer blends has significant influence on their density and rheological...

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Finite element description of nonlinear viscoelastic behaviour of technical fabric

Publikacja

P. Kłosowski
W. Komar
K. Woznica

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2009

W pracy podano propozycję nieliniowego modelowania zachowania się tkaniny technicznej. Podano wyniki identyfikacji i zweryfikowano poprzez numeryczną symulację prób laboratoryjnych

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Hydrogen embrittlement of X2CrNiMoCuN25-6-3 super duplex stainless steel welded joints under cathodic protection

Publikacja

The effect of cathodic polarization conditions on hydrogen degradation of X2CrNiMoCuN25-6-3 super duplex stainless steel welded joints, obtained using flux cored arc and submerged arc welding methods, was evaluated. Slow strain rate tensile tests of base material and welded specimens, ferrite content measurements, scanning electron microscopy observations, and statistical analysis were performed. It was found that hydrogenation...

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The influence of combination of binding agents on fatigue properties of deep cold in-place recycled mixtures in Indirect Tensile Fatigue Test (ITFT)

Publikacja

The publication presents fatigue properties of cold recycled mixtures for eight combinations of binding agents (cement and bituminous emulsion). Cold recycled mixtures were evaluated in Indirect Tensile Fatigue Test (ITFT) at the temperature of 20 C in controlled stress mode. As a function of horizontal stress, fatigue life is strongly influenced by combination of the binding agents. When fatigue life is analyzed as a function...

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Mechanical and fracture properties of concrete reinforced with recycled and industrial steel fibers using Digital Image Correlation technique and X-ray micro computed tomography

Publikacja

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2018

Paper presents investigation of fracture phenomenon in plain concrete and in concrete reinforced with both recycled steel fibers (RSF) and industrial steel fibers (ISF). The wedge splitting test (WST), which enables stable crack propagation for quasi-brittle materials, was carried out on 75 75 75 mm cube samples. Initially, fracture process zone development was investigated only on the surface of samples using Digital Image Correlation...

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Asphalt concrete subjected to long-time loading at low temperatures – Deviations from the time-temperature superposition principle

Publikacja

The article presents the observed deviations from the time-temperature superposition principle of asphalt concretes, tested in the bending beam creep test at low temperatures for a long time of loading. In almost all tested asphalt concretes, deviations appeared after 500 s of loading at the temperature of -10 C. Some types of bitumen presented deviations at other temperatures – usually the harder the grade of the bitumen, the...

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Ground tire rubber thermo-mechanically devulcanized in the presence of waste engine oil as asphalt modifier

Publikacja

Y. Li
A. Shen
Z. Lyu
S. Wang
K. Formela
G. Zhang

Cross-linked elastomers network is main limitation for industrial usage of ground tire rubber (GTR) as asphalts’ and road pavements modifier. GTR was thermo-mechanically devulcanized via extrusion in the presence of waste engine oil (WEO) at temperature ranges from 150 to 280 °C. Combined impact of WEO content and extruder barrel temperature on the change of cross-linked structure of degraded GTR (DTGR) was investigated through...

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Effect of bitumen characteristics obtained according to EN and Superpave specifications on asphalt mixture performance in low-temperature laboratory tests

Publikacja

The paper aims to identify those characteristics of bitumen which have the greatest impact on asphalt mixture low-temperature performance. It was observed that stiffness and m-value of bitumen from BBR test were moderately related to stiffness and m-value of asphalt mixture obtained from 3 PB test. Simultaneously those rheological properties significantly impact on cryogenic stresses induced during TSRST test. The multiple regression...

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A novel heterogeneous model of concrete for numerical modelling of ground penetrating radar

Publikacja

J. Lachowicz
M. Rucka

The ground penetrating radar (GPR) method has increasingly been applied in the non-destructive testing of reinforced concrete structures. The most common approach to the modelling of radar waves is to consider concrete as a homogeneous material. This paper proposes a novel, heterogeneous, numerical model of concrete for exhaustive interpretation of GPR data. An algorithm for determining the substitute values of the material constants...

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Reference-free determination of debonding length in reinforced concrete beams using guided wave propagation

Publikacja

This paper presents theoretical and experimental investigations of guided wave propagation in reinforced concrete beams, with pre-existing debonding between steel rebars and concrete blocks, for the purpose of damage detection. The primary aim of these investigations was a detailed analysis of the possible applications of wave propagation in single and multiple debonding detection in reinforced concrete structures and reference-free...

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Influence of cooling rate and additives on low-temperature properties of asphalt mixtures in the TSRST

Publikacja

The paper presents the results and analysis of low-temperature properties of asphalt mixtures according to Thermal Stress Restrained Specimen Test (TSRST) and Indirect Tensile Test methods. Different groups of bitumen were investigated: neat, SBS-modified and highly SBS-modified. Influence of cooling rates (1 C/h, 3 C/h, 5 C/h and 10 C/h) and additives (aramid fibres and crumb rubber) was identified as well. Moreover, for each...

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Application of Electrochemical Impedance Spectroscopy to evaluate cathodically protected coated steel in seawater

Publikacja

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2018

Two types of organic coated carbon steel (S235JR2 grade) electrodes were exposed to artificial seawater environment. One prepared type was defect free while the other one had an intentionally introduced φ0,5 cm coating defect. Both kinds of samples were polarized during the exposure to four potentials corresponding to four different cathodic protection levels. Evolution of their EIS spectra is presented in this paper. Results obtained...

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Monte Carlo simulations of the fracture resistance of an asphalt pavement layer

Publikacja

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2024

The purpose of the proposed numerical model is to analyze the cracking of the wearing course in a pavement overlay, assuming a pre-existing crack that passes through the binding layer and base. The computations employed the author's simulation-based Monte Carlo material model, which describes the failure process of a Semi-Circular Bend (SCB) specimen during standard laboratory testing of asphalt concrete. A key feature of this...

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Influence of low-temperature physical hardening on stiffness and tensile strength of asphalt concrete and stone mastic asphalt

Publikacja

J. Judycki

This paper presents laboratory testing of stiffness modulus and indirect tensile strength of three asphalt concrete (AC) and three stone mastic asphalt (SMA) mixes after isothermal storage at temperature of -20oC, at different time intervals up to 16 days. The tests under repeated dynamic loading showed physical hardening of all tested mixes which was manifested by an evident increase of their stiffness moduli after isothermal...

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Electrochemical investigations on the corrosion behaviour of reinforcing steel in diatomite- and zeolite-containing concrete exposed to sulphuric acid

Publikacja

H. Gerengi
A. Jażdżewska

- CONSTRUCTION AND BUILDING MATERIALS - Rok 2013

Corrosion is a major concern for most structural applications. Its detrimental effect significantly reduces the life of metallic components. This paper presents the results of an experimental investigation of corrosion in the steel reinforcement of concrete samples having three different substituents: 20% diatomite, 20% zeolite, and a reference without zeolite or diatomite. All concrete specimens were subjected to a solution of...

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Determination of causes of accelerated local corrosion of austenitic steels in water supply systems

Publikacja

This paper concerns an inspection of a water supply system, made of AISI 304 steel, which showed signs of local corrosion at the weld. Such corrosion caused material perforation after very short periods of operation. It was revealed that steel was sensitised during the welding process. It was also proven that chromium micro-segregation occurred in the alloy leading to galvanic cell formation which initialised the process of pitting...

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Simultaneous impedance and volumetric studies and additionally potentiodynamic polarization measurements of molasses as a carbon steel corrosion inhibitor in 1M hydrochloric acid solution

Publikacja

The inhibition effect of molasses on the corrosion of low carbon steel in 1M hydrochloric acid solution was investigated by volumetric and electrochemical measurements. Potentiodynamic polarization and dynamic electrochemical impedance spectroscopy (DEIS) results were obtained and compared with to those, obtained with the hydrogen evolution technique. All results indicate that molasses functioned as a good inhibitor in 1M hydrochloric...

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Mechanical properties for preliminary design of structures made from PVC coated fabric

Publikacja

In this paper, laboratory tests necessary for the identification of non-linear elastic immediate properties of the PVC coated polyester fabric (like AF 9032) are described. The material parameters are specified on the basis of the uniaxial tensile tests in the warp and weft directions as well as on the base of the biaxial tensile tests. For the identification process techniques based on the least squares method are used. The authors...

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Thermal stabilization and permanent deformation resistance of LWA/PCM-modified asphalt road surfaces

Publikacja

This paper presents the results of attempts at reducing the problem of solar overheating of asphalt road pavement surfaces, resulting in weakening and accelerated destruction of the aforementioned structures. To protect pavement surfaces against periodic overheating, standard asphalt mixture AC 16 W 35/50, used for binder course, has been modified by replacing one of the aggregate fractions from the mineral mixture with lightweight...

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Comparison of low-temperature cracks intensity on pavements with high modulus asphalt concrete and conventional asphalt concrete bases

Publikacja