Evaluation of Rebound Hammer Test as a Combined Procedure Used with Drill Core Testing for Evaluation of Existing Structures

2011 ◽  
pp. 341-346
Author(s):  
S. Yeşilmen
Keyword(s):  
Drill Core ◽  
Rebound Hammer ◽  
Combined Procedure ◽  
Existing Structures

scholarly journals Rebound Hammer Test: An Investigation into Its Reliability in Applications on Concrete Structures

2020 ◽  
Vol 2020 ◽  
pp. 1-11
Author(s):  
Antonio Brencich ◽  
Rossella Bovolenta ◽  
Valeria Ghiggi ◽  
Davide Pera ◽  
Paolo Redaelli
Keyword(s):  
Building Materials ◽  
Concrete Strength ◽  
Research Work ◽  
Third Party ◽  
Test Reliability ◽  
Surface Finishing ◽  
Engineering Practice ◽  
Rebound Hammer ◽  
Existing Structures ◽  
Concrete Maturity

The issue of concrete strength often arises in civil engineering practice, either due to quality control of new constructions or due to the assessment of existing structures. To this aim, one of the most widely spread techniques is the rebound hammer (Schmidt hammer) test, for which calibration is still related to the original Schmidt curve dating back to the early 50’s. In spite of the large amount of research work performed in the last decades, the uncertainties of the rebound test are still not clearly quantified and open to further insight. This paper presents and discusses a wide research campaign on laboratory specimens and on third-party specimens delivered to the Laboratory for Building Materials of the University of Genoa, Italy, for standard quality controls. While it is well known that moisture content, surface finishing, and concrete maturity strongly affect the test result, the effect of the stress state has not yet been studied and is found in this research to be a further parameter affecting the test reliability. The final outcome of all the uncertainties is variability in estimated concrete strength as large as ±70%; additionally, some issues are discussed on the intrinsic uncertainty of this test. As already demonstrated by many authors, the results of this research also show that a universal calibration curve to be used for any concrete, in any condition, conceptually does not exist.

scholarly journals Experimental Study on the Compressive Strength of Big Mobility Concrete with Nondestructive Testing Method

2012 ◽  
Vol 2012 ◽  
pp. 1-6 ◽  
Author(s):  
Huai-Shuai Shang ◽  
Ting-Hua Yi ◽  
Lu-Sheng Yang
Keyword(s):  
Experimental Study ◽  
Nondestructive Testing ◽  
Regression Method ◽  
Construction Site ◽  
Rebound Hammer ◽  
Existing Structures ◽  
Testing Method ◽  
Rebound Number ◽  
Nondestructive Testing Method ◽  
Set Up

An experimental study of C20, C25, C30, C40, and C50 big mobility concrete cubes that came from laboratory and construction site was completed. Nondestructive testing (NDT) was carried out using impact rebound hammer (IRH) techniques to establish a correlation between the compressive strengths and the rebound number. The local curve for measuring strength of the regression method is set up and its superiority is proved. The rebound method presented is simple, quick, and reliable and covers wide ranges of concrete strengths. The rebound method can be easily applied to concrete specimens as well as existing concrete structures. The final results were compared with previous ones from the literature and also with actual results obtained from samples extracted from existing structures.

scholarly journals Adapting Artificial Intelligence to Improve In Situ Concrete Compressive Strength Estimations in Rebound Hammer Tests

2020 ◽  
Vol 7 ◽  
Author(s):  
Yu Ren Wang ◽  
Yen Ling Lu ◽  
Dai Lun Chiang
Keyword(s):  
Artificial Intelligence ◽  
Compressive Strength ◽  
Prediction Models ◽  
Concrete Compressive Strength ◽  
Concrete Material ◽  
Rebound Hammer ◽  
Existing Structures ◽  
Core Samples ◽  
Using Data

Compressive strength is probably one the most crucial properties of concrete material. For existing structures, core samples are drilled and tested to obtain the concrete compressive strength. Many times, taking core samples is not feasible, and as a result, nondestructive methods to examine the concrete are required. The rebound hammer test is one of the most popular methods to estimate concrete compressive strength without causing damage to the existing structure. The test is inexpensive and can be easily conducted compared to other nondestructive testing methods. Also, concrete compressive strength estimations can be obtained almost instantly. However, previous results have shown that concrete compressive strength estimations obtained from rebound hammer tests are not very accurate. As a result, this research attempts to apply artificial intelligence prediction models to estimate concrete compressive strength using data from in situ rebound hammer tests. The results show that artificial intelligence methods can effectively improve in situ concrete compressive strength estimations in rebound hammer tests.

Prediction of Concrete Compressive Strength by Means of Combined Non-Destructive Testing

2014 ◽  
Vol 894 ◽  
pp. 77-81 ◽  
Author(s):  
Giovanna Concu ◽  
Barbara de Nicolo ◽  
Luisa Pani ◽  
Nicoletta Trulli ◽  
Monica Valdés
Keyword(s):  
Compressive Strength ◽  
Non Destructive Testing ◽  
Concrete Compressive Strength ◽  
Destructive Testing ◽  
Empirical Formulas ◽  
Rebound Hammer ◽  
Existing Structures ◽  
Non Invasive ◽  
Compressive Strength Test ◽  
Non Destructive

The problem of estimating mechanical properties of buildings materials is a major issue in civil engineering, especially when dealing with existing structures. In such occasion a valuable help is given by Non Destructive Testings, which allow materials characteristics to be evaluated in a non-invasive way. This paper analyses the efficacy of the SonReb method - a non destructive technique which statistically combines the results of Ultrasonic and Rebound Hammer Testing in predicting concrete compressive strength. The SonReb method has been applied on concrete specimens later on exposed to compressive strength test. The effectiveness of several empirical formulas expressing SonReb results is illustrated and discussed.

Autism and Neurodiversity: Addressing Concerns and Offering Implications for the School-Based Speech-Language Pathologist

2020 ◽  
pp. 1-7
Author(s):  
Laura S. DeThorne ◽  
Kelly Searsmith
Keyword(s):  
Service Provision ◽  
Individualized Education Program ◽  
Institutional Constraints ◽  
Individualized Education ◽  
Existing Structures ◽  
Eligibility Determination ◽  
Speech Language Pathologist ◽  
School Based ◽  
Key Points ◽  
C Center

Purpose The purpose of this article is to address some common concerns associated with the neurodiversity paradigm and to offer related implications for service provision to school-age autistic students. In particular, we highlight the need to (a) view first-person autistic perspectives as an integral component of evidence-based practice, (b) use the individualized education plan as a means to actively address environmental contributions to communicative competence, and (c) center intervention around respect for autistic sociality and self-expression. We support these points with cross-disciplinary scholarship and writings from autistic individuals. Conclusions We recognize that school-based speech-language pathologists are bound by institutional constraints, such as eligibility determination and Individualized Education Program processes that are not inherently consistent with the neurodiversity paradigm. Consequently, we offer examples for implementing the neurodiversity paradigm while working within these existing structures. In sum, this article addresses key points of tension related to the neurodiversity paradigm in a way that we hope will directly translate into improved service provision for autistic students. Supplemental Material https://doi.org/10.23641/asha.13345727

CREDO RADON UA – INFORMATION MODEL FOR CALCULATION OF ROAD CONSTRACTION

2019 ◽  
pp. 34-42
Author(s):  
Volodymyr Karedin ◽  
Nadiya Pavlenko
Keyword(s):  
Design Process ◽  
Static Loading ◽  
Computer Aided Design ◽  
Experimental Studies ◽  
Construction Materials ◽  
Residual Deformation ◽  
Road Construction ◽  
Information Support ◽  
Existing Structures ◽  
Road Pavement

CREDO RADON UA software provides an automated calculation of the strength of the pavement structures of non-rigid and rigid types, as well as the calculation of the strengthening of existing structures. In the article, one can see the main features and functionality of the CREDO RADON UA software, the main points in the calculations according to the new regulations. Information support of the design process includes necessary databases, informational and helping materials that make up the full support of the pavement design process. The concept of CREDO RADON UA 1.0 software is made on the use of elasticity theory methods in calculations of initial information models of pavements. Performing optimization calculations, the roadwear in CREDO RADON UA is designed in such a way that no unacceptable residual deformation occurs under the influence of short-term dynamic or static loading in the working layer of the earth bed and in the structural layers during the lifetime of the structure. The calculation algorithms were made in accordance with the current regulatory documents of Ukraine. CREDO RADON UA software allows user to create information bases on road construction materials and vehicles as part of the traffic flow for calculations. The presented system of automated modeling makes it easier for the customer to control the quality of design solutions, to reasonably assign designs to layers of reinforcement, to quickly make comparisons of calculations of different designs for the optimal use of allocated funds. Prospects for further improvement of the program should be the results of theoretical and experimental studies on filling the databases, which are used as information support for automated design of road structures. Keywords: CREDO RADON UA, road, computer-aided design, repair project, road pavement, strengthening, construction, rigid pavement, elasticity module, a transport stream, calculation method, information support, dynamic or static loading.

UPGRADING OF LOCKING SUPPORTS OF ROD-TYPE DOWNHOLE PUMPS

2020 ◽  
Author(s):  
H.K Kaderov ◽  
◽  
S.O. Kireev ◽  
M.V. Korchagina ◽  
A.R. Lebedev ◽  
...  
Keyword(s):  
High Variability ◽  
Existing Structures ◽  
Conical Surfaces

The article provides analysis of existing structures of lock supports for fixation of plug-in rod-type downhole pumps. Based on the analysis, the connection of the lock support elements and the pump is evaluated. Description is given of the new structure of the lock support equipped with a set of spring-loaded and radially extendable sliders. The latter have conical surfaces interacting in forward and reverse directions with pump armature. The proposed design has high variability, which allows to perform modeling of the product both at the stage of design and at the stage of implementation.

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