Determination of space behind pre-cast concrete elements in tunnels using GPR

2010 ◽  
Author(s):  
A Lalague ◽  
I Hoff
Keyword(s):  
Cast Concrete ◽  
Concrete Elements

scholarly journals Analyzing of Coatings on Steel - Reinforced Concrete Elements by Mobile NMR

2016 ◽  
Vol 62 (1) ◽  
pp. 65-82 ◽  
Author(s):  
J. Orlowsky
Keyword(s):  
Reinforced Concrete ◽  
Potential Effect ◽  
Building Site ◽  
Steel Reinforced Concrete ◽  
Mobile Nmr ◽  
The Individual ◽  
First Time ◽  
Concrete Elements ◽  
Non Destructive

Abstract A large number of infrastructural concrete buildings are protected against aggressive environments by coating systems. The functionality of these coating systems is mainly affected by the composition and thickness of the individual polymeric layers. For the first time ever, a mobile nuclear magnetic resonance (NMR) sensor allows a non-destructive determination of these important parameters on the building site. However, before this technique can be used on steel-reinforced concrete elements, the potential effect of the reinforcement on the measurement, i.e. the NMR signal, needs to be studied. The results show a shift of the NMR profile as well as an increase of the signals amplitude in the case of the reinforced samples, while calculating the thickness of concrete coating leading to identical results.

scholarly journals TO DETERMINATION OF THE CRACKING MOMENT FOR BENDING REINFORCED CONCRETE ELEMENTS WITH ACCOUNT OF PLASTIC DEFORMATIONS OF CONCRETE IN THE TENSION AREA

2018 ◽  
Vol 3 (3) ◽  
pp. 30-38
Author(s):  
О.В. Радайкин ◽  
Oleg Radaykin
Keyword(s):  
Reinforced Concrete ◽  
Deformation Model ◽  
Conventional Concrete ◽  
Class A ◽  
Standard Calculation ◽  
Plasticity Coefficient ◽  
Concrete Elements ◽  
Nonlinear Deformation Model ◽  
Good Agreement

At the standard calculation of the cracking moment for bending reinforced concrete elements the plasticity coefficient γ is normally used, which according to SP 63.13330.2012 is 35% less than in the old SNiP 2.03.01-84*. The question arises, what is the reason for such a noticeable difference and which of the methods gives more reliable results? This article seeks to answer this question. For this purpose the physical meaning of the coefficient γ was considered in detail, with the usage of a nonlinear deformation model of a normal section. A calculation formula for γ depending on an element’s reinforcement degree was obtained, which is valid for conventional concrete of B15-B35 class. A comparison of the calculated cracking moment according to the proposed method with experiments by the other authors was carried out. A good agreement of results was observed.

scholarly journals Laser System for Testing Early Shrinkage of Concrete Elements in Conjuction with the Deterioration of the Setting Time

2016 ◽  
Vol 16 (2) ◽  
pp. 25-34
Author(s):  
Jacek Gołaszewski ◽  
Tomasz Ponikiewski ◽  
Grzegorz Cygan ◽  
Małgorzata Gołaszewska
Keyword(s):  
Concrete Beams ◽  
Setting Time ◽  
Laser System ◽  
Scratch Resistance ◽  
Sound Waves ◽  
Concrete Elements ◽  
Speed Propagation

Abstract The paper presents a method for testing the shrinkage of concrete beams with dimensions of 10x10x50cm. Measurements followed from setting into the form until 24 hours after setting. It was used modified TLS system, which originally was meant for the determination of changes in the length of thin-mortar. Simultanously measured were the changes of speed propagation of sound waves by Vikasonic, what allows to specify the setting time of binders. It could be a base for determining the scratch resistance of the concrete in the first 24 hours after casting.

Bearing Capacity of Common and Damaged CFRP-Strengthened R. C. Beams Subject to High-Level Low-Cycle Loading

2019 ◽  
Vol 968 ◽  
pp. 185-199
Author(s):  
Vasyl M. Karpiuk ◽  
Yulia A. Syomina ◽  
Diana V. Antonova
Keyword(s):  
Bearing Capacity ◽  
Repeated Loading ◽  
Calculation Methods ◽  
Design Standards ◽  
Deformation Method ◽  
Current Design ◽  
Cycle Loading ◽  
High Level ◽  
Concrete Elements

In the course of operation or armed hostilities the span r.c. structures are subject to substantial damage and considerable reduction of their bearing capacity, especially under low-cycle repeated loading. In this connection it becomes necessary to renew their operation capacity and/or improve their bearing capacity. However, the current design standards contain no recommendations as to determination of the residual bearing capacity of such structures and calculation of their reinforcement. There are methods of the operation capacity renewal and reinforcement of the structures by increasing their sections adding metal or reinforced concrete elements. Still, the calculation methods of such reinforcement are also imperfect. It is proposed to renew operation capacity of such structures by strengthening their tensioned parts with CFRP; the performed experimental research will provide the basis for calculating bearing capacity of said structures with the aid of the deformation method improved by the authors.

Development and Investigation of Mechanical Properties of Glass Fiber Reinforced Concrete

2015 ◽  
Vol 725-726 ◽  
pp. 642-647
Author(s):  
Mikhail Beliaev ◽  
Sergey Semenov ◽  
Oleg Stolyarov
Keyword(s):  
Glass Fiber ◽  
High Strength ◽  
Fiber Reinforced Concrete ◽  
Building Structures ◽  
Fibrous Materials ◽  
High Corrosion Resistance ◽  
Glass Fiber Reinforced ◽  
Concrete Elements ◽  
Concrete Reinforcement

Nowadays, new types of concrete reinforcement are finding increasing use in civil engineering applications. The use of fibrous materials as reinforcement for building structures gives opportunity for the manufacturing of concrete elements with reduced thickness, high strength, and high corrosion resistance. This paper includes development and determination of mechanical behavior of concrete reinforced with glass fiber, roving and composite reinforcement.

FORME DI LETTURA, FORME DI CULTURA

Nuncius ◽  
1999 ◽  
Vol 14 (1) ◽  
pp. 3-18
Author(s):  
GABRIELE BARONCINI
Keyword(s):  
Text Reading ◽  
Printed Text ◽  
Cultural Forms ◽  
Concrete Elements

Abstracttitle SUMMARY /title This essay tries an examination of the verbal and non-verbal lections of incunabula, conducted in function of the reader's culture. Are put under analysis all those subjective interventions that allow to gather in the text the cultural forms interacting and modelling a text reading as well as the determination of its meaning. However the printed text itself already contains objective and concrete elements predeterming the form of lection. Various authors are involved in the essay, such as among others Leibniz, Descartes and Nicholas de Lyra. From a general standpoint this is an attempt having the aim of singling out both facts and concepts useful to reconstruct, at least partially, the complex and elusive act of reading.

scholarly journals ASSESSMENT OF THE DEPTH AND RATE OF CORROSION IN STEEL REINFORCEMENT OF REINFORCED CONCRETE CULVERTS

2020 ◽  
Author(s):  
Alexandr Vasiliev ◽  
Svetlana Daškevič
Keyword(s):  
Reinforced Concrete ◽  
Protective Layer ◽  
Corrosion Damage ◽  
Steel Reinforcement ◽  
Operating Conditions ◽  
Protective Properties ◽  
Open Atmosphere ◽  
Concrete Elements ◽  
Corrosion State

Based on the results of many research years on concrete carbonisation: both immediately after manufacture (using heat-moisture treatment) and in reinforced concrete elements operated for the periods of various length (in an open atmosphere); the effect of carbonisation on the change in the protective properties of concrete in relation to steel reinforcement; for determination of the dependence of the corrosion state of steel reinforcement on the degree of concrete carbonisation in the area of steel reinforcement; the obtained regression dependences of the change (by time in the cross section) of the degree of concrete carbonisation of various classes in strength, – the analysis of the time of the onset of the boundary values of the degrees of concrete carbonisation (strength classes C12/15–C30/37) for the operating conditions of the open atmosphere was performed. Based on it, the regression dependences of the time variation of the depth of corrosion damage of steel reinforcement were construed (for fixed thicknesses of the concrete protective layer). The obtained nature of dependences made it possible to offer, in a general form, the regression dependences of the depth of corrosion damage and corrosion rate of steel reinforcement for concretes (strength classes C12/15–C30/37) for operating conditions in open atmosphere.

scholarly journals Rebound testing of cylindrical spun-cast concrete elements

2011 ◽  
Vol 55 (2) ◽  
pp. 129 ◽  
Author(s):  
István Völgyi ◽  
György Farkas
Keyword(s):  
Cast Concrete ◽  
Concrete Elements
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