scholarly journals Ultrasonic Assessment of the Concrete Residual Strength after a Real Fire Exposure

Buildings ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 154
Author(s):  
Roman Wróblewski ◽  
Bohdan Stawiski
Keyword(s):  
Residual Strength ◽  
Heated Surface ◽  
Pulse Velocity ◽  
Strength Reduction ◽  
Fire Damage ◽  
Fire Exposure ◽  
Fire Effect ◽  
Surface Examination ◽  
Ultrasonic Assessment ◽  
Ultrasound Pulse

After a fire, the assessment of concrete residual strength can be a challenge. Since the strength reduction depends on the distance from the heated surface examination based on destructive test, i.e., core samples, is not precise enough. Therefore, more detailed methods can establish the influence of the high temperature in the zone, which no longer has visible cracks. That method can be used to assess layer thickness to remove due to the fire damage. The Ultrasound Pulse Velocity (UPV) method with point heads was used in the paper to examine samples taken from a structure after the real fire. Moreover, to make the analysis more precise, an effect associated with the porosity in concrete was also considered to separate pure fire effect.

scholarly journals Identifying Blunt Force Traumatic Injury on Thermally Altered Remains: A Pilot Study Using Sus scrofa

Biology ◽  
2022 ◽  
Vol 11 (1) ◽  
pp. 87
Author(s):  
Kamryn Keys ◽  
Ann H. Ross
Keyword(s):  
Pilot Study ◽  
Forensic Anthropology ◽  
Sus Scrofa ◽  
Traumatic Injury ◽  
Human Remains ◽  
Fire Damage ◽  
Fire Exposure ◽  
Blunt Force ◽  
Blunt Force Trauma ◽  
Anthropological Literature

In forensic scenarios involving homicide, human remains are often exposed to fire as a means of disposal and/or obscuring identity. Burning human remains can result in the concealment of traumatic injury, the creation of artifacts resembling injury, or the destruction of preexisting trauma. Since fire exposure can greatly influence trauma preservation, methods to differentiate trauma signatures from burning artifacts are necessary to conduct forensic analyses. Specifically, in the field of forensic anthropology, criteria to distinguish trauma from fire signatures on bone is inconsistent and sparse. This study aims to supplement current forensic anthropological literature by identifying criteria found to be the most diagnostic of fire damage or blunt force trauma. Using the skulls of 11 adult pigs (Sus scrofa), blunt force trauma was manually produced using a crowbar and flat-faced hammer. Three specimens received no impacts and were utilized as controls. All skulls were relocated to an outdoor, open-air fire where they were burned until a calcined state was achieved across all samples. Results from this experiment found that blunt force trauma signatures remained after burning and were identifiable in all samples where reassociation of fragments was possible. This study concludes that distinct patterns attributed to thermal fractures and blunt force fractures are identifiable, allowing for diagnostic criteria to be narrowed down for future analyses.

scholarly journals Recycled Concrete Aggregate for Medium-Quality Structural Concrete

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4612
Author(s):  
Dong Viet Phuong Tran ◽  
Abbas Allawi ◽  
Amjad Albayati ◽  
Thi Nguyen Cao ◽  
Ayman El-Zohairy ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Coarse Aggregate ◽  
Pulse Velocity ◽  
Recycled Concrete ◽  
Concrete Aggregate ◽  
Predictive Equation ◽  
Recycled Concrete Aggregate ◽  
Structural Concrete ◽  
Medium Quality ◽  
Ultrasound Pulse

This paper reports an evaluation of the properties of medium-quality concrete incorporating recycled coarse aggregate (RCA). Concrete specimens were prepared with various percentages of the RCA (25%, 50%, 75%, and 100%). The workability, mechanical properties, and durability in terms of abrasion of cured concrete were examined at different ages. The results reveal insignificant differences between the recycled concrete (RC) and reference concrete in terms of the mechanical and durability-related measurements. Meanwhile, the workability of the RC reduced vastly since the replacement of the RCA reached 75% and 100%. The ultrasound pulse velocity (UPV) results greatly depend on the porosity of concrete and the RC exhibited higher porosity than that of the reference concrete, particularly at the transition zone between the RCA and the new paste. Therefore, the sound transmission in the RC required longer times than that in the reference concrete. Moreover, a predictive equation relating the compressive strength to the UPV was developed.

scholarly journals Effectiveness and Compatibility of a Novel Sustainable Method for Stone Consolidation Based on Di-Ammonium Phosphate and Calcium-Based Nanomaterials

Materials ◽  
2019 ◽  
Vol 12 (18) ◽  
pp. 3025 ◽  
Author(s):  
Cecilia Pesce ◽  
Ligia M. Moretto ◽  
Emilio F. Orsega ◽  
Giovanni L. Pesce ◽  
Marco Corradi ◽  
...  
Keyword(s):  
Ammonium Phosphate ◽  
Pulse Velocity ◽  
X Ray ◽  
Artistic Value ◽  
Physical Chemical ◽  
Stone Consolidation ◽  
Colour Measurements ◽  
Combined Use ◽  
Water Absorption Test ◽  
Ultrasound Pulse

External surfaces of stones used in historic buildings often carry high artistic value and need to be preserved from the damages of time, especially from the detrimental effects of the weathering. This study aimed to test the effectiveness and compatibility of some new environmentally-friendly materials for stone consolidation, as the use thereof has been so far poorly investigated. The treatments were based on combinations of an aqueous solution of di-ammonium phosphate (DAP) and two calcium-based nanomaterials, namely a commercial nanosuspension of Ca(OH)2 and a novel nanosuspension of calcite. The treatments were applied to samples of two porous stones: a limestone and a sandstone. The effectiveness of the treatments was assessed using scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy, Fourier-transform infrared spectroscopy, ultrasound pulse velocity test, colour measurements, and capillary water absorption test. The results suggest that the combined use of DAP and Ca-based nanosuspensions can be advantageous over other commonly used consolidants in terms of retreatability and physical-chemical compatibility with the stone. Some limitations are also highlighted, such as the uneven distribution and low penetration of the consolidants.

RESIDUAL STRENGTH OF SANDWICH STRUCTURE SUBJECTED TO LOW VELOCITY IMPACT

2006 ◽  
Vol 20 (25n27) ◽  
pp. 4384-4389 ◽  
Author(s):  
KI-WEON KANG ◽  
JUNG-KYU KIM ◽  
SEONG-KYUN CHEONG ◽  
HEUNG-SEOB KIM
Keyword(s):  
Residual Strength ◽  
Sandwich Structure ◽  
Strength Reduction ◽  
Low Velocity Impact ◽  
Low Velocity ◽  
Reduction Behavior ◽  
Static Tests ◽  
Velocity Impact ◽  
Impact Tester ◽  
The Impact

The goals are to identify the strength reduction behavior and its statistical properties of sandwich structure subjected to low velocity impact. For these, the impact tests were performed using the impact tester and the damages are inspected by SAM. And then, subsequent static tests are conducted under flexural loading for the impacted structures. The strength reduction behavior is evaluated via the residual strength prediction model. Also, a statistical model is developed to identify the fluctuation of residual strength. The model well describes the distribution of residual strength.

Assessment of mechanical and fire resistance for hybrid nano-clay and steel fibres concrete at different curing ages

2019 ◽  
Vol 11 (2) ◽  
pp. 189-203 ◽  
Author(s):  
Ola Bakr Shalby ◽  
Hala Mohamed Elkady ◽  
Elsayed Abdel Raouf Nasr ◽  
Mohamed Kohail
Keyword(s):  
Compressive Strength ◽  
Residual Strength ◽  
Low Cost ◽  
Partial Replacement ◽  
Fire Exposure ◽  
Content Type ◽  
Steel Fibres ◽  
Concrete Properties ◽  
Nano Clay ◽  
Concrete Mix

Purpose Nano-Clay (NC) is reported as a candidate partial replacement for cement, due to its abundance and relatively low cost - beside reported promotion of different concrete properties. On the other hand, Steel Fibres (SF) has proven to have a positive effect on post fire exposure residual strength of concrete. This paper aims to present the outcomes of a comprehensive research program assessing a hybrid mix between NC and SF in concrete mixtures (NCSF-CRETE). Design/methodology/approach Physical chemical and physical characterization of NC is performed using different tools as XRF spectrometer, and TEM micrograph. Fresh concrete properties of NSCF-CRETE as slump and air content are investigated. Enhancement in permeability using NSCF is verified by comparing its resistance to the penetration of chlorides resistance with regular concrete mix. Besides, the proposed NCSF-CRETE compressive strength is evaluated compared to mixes with NC and SF each used separately at different curing ages. Besides, NSCF and compared mixes are exposed to an indirect fire testing program – two hours exposure – for: 300, 450 and 600°C. Degradation in compressive strength was investigated after exposure to different temperatures and percentage of residual strength is reported. Findings Results indicated an improved performance of NCSF -CRETE of about 40% compared to regular concrete in compressive strength at normal conditions. This improvement extended to its behavior when subjected to indirect fire exposure NSCF also maintained 40% more strength than the residual in regular concrete mix – which suffered severe damage – after 2 h exposure to 600°C. Originality/value Using NCSF-Crete allows retrofitting the structure after exposure to such drastic conditions.

Recycled Concrete Using Crushed Construction Waste Bricks Subject to Elevated Temperatures

2010 ◽  
Vol 152-153 ◽  
pp. 1-10
Author(s):  
Chung Ming Ho ◽  
Wei Tsung Tsai
Keyword(s):  
Compressive Strength ◽  
Residual Strength ◽  
Elevated Temperatures ◽  
Plain Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Recycled Concrete ◽  
Fine Aggregate ◽  
Term Performance

The objectives of this paper are to find the compressive strength and ultrasonic pulse velocity (UPV) of recycled concrete with various percentages of natural fine aggregate replaced by Recycled brick fine aggregate (RBFA) as well as the residual strength and residual UPV of recycled concrete subjected to elevated temperatures. Experiment results showed that the compressive strength and UPV decreased as amount of RBFA in concrete increased, the long-term performance of compressive strength and UPV development increased as the RBFA content increased. The residual strength of recycled concrete increased slightly after heating to 300°C and the residual UPV of recycled concrete decreased gradually as the exposed temperature increased beyond 300°C. In the range of 580 -800°C, recycled concrete lost most of its original compressive strength and UPV. After subjected to the temperature of 800°C, compared to plain concrete, recycled concrete with 100% RBFA had a greater discount rate of compressive strength and UPV of the order of 5-15% and 6-10%. Regression analysis results revealed that the residual strength and residual UPV of recycled concrete had a high relevance after elevated temperatures exposure.

Overview of Research Progress for Concrete-Filled Steel Tubular Columns after Exposure to Fire

2014 ◽  
Vol 638-640 ◽  
pp. 197-201
Author(s):  
Yan Chong Pan ◽  
Guo Hui Wang ◽  
Kai Xiang
Keyword(s):  
Mechanical Properties ◽  
Residual Strength ◽  
Fire Safety ◽  
Axial Load ◽  
Research Progress ◽  
Building Structures ◽  
Fire Exposure ◽  
Tubular Columns ◽  
Cfst Columns ◽  
Exposure Process

Fire safety is one of the most important performances index to evaluate building structures. The property of building members after exposure to fire involved with the safety of buildings after fire, and it will be necessary to estimate the post-fire residual strength of the structure in order to decide the appropriate strategy for repair. This paper summarizes the research progress of concrete-filled steel tubular (CFST) columns. Basic mechanical properties of conventional CFST columns after exposure to fire, CFST columns after the whole fire exposure process under sustained axial load, and CFST columns with special forms after exposure to fire are discussed.

scholarly journals Patrimônio pétreo paulistano: análise sob a ótica de propagação de ondas ultrassônicas

2018 ◽  
Vol 15 (30) ◽  
pp. 229
Author(s):  
Eliane Aparecida Del Lama ◽  
Alexander Martin Silveira Gimenez ◽  
Danielle Grossi ◽  
Diego Ferreira Ramos Machado ◽  
Luciane Kuzmickas ◽  
...  
Keyword(s):  
Analytical Method ◽  
Pulse Velocity ◽  
Sao Paulo ◽  
The State ◽  
São Paulo ◽  
Depth Of Penetration ◽  
Stone Monuments ◽  
The City ◽  
Non Destructive ◽  
Ultrasound Pulse

A medição da velocidade de propagação de ondas ultrassônicas, método de análise não destrutivo, é uma técnica eficiente para avaliar o estado de conservação da rocha e a profundidade de penetração de consolidantes em monumentos. Este trabalho objetiva analisar monumentos pétreos da cidade de São Paulo com base nesta técnica. A superfície de acabamento é um ponto chave na obtenção dos dados, uma vez que superfícies polidas permitem o perfeito acoplamento dos transdutores, favorecendo a execução do ensaio de forma adequada. Os dados apontam rochas não alteradas ou ausência de fraturamento nos monumentos analisados. Abstract: Ultrasound pulse velocity, a non-destructive analytical method, is an efficient technique to evaluate the state of conservation of the rock and the depth of penetration of consolidants in monuments. This work aims to analyze stone monuments of the city of São Paulo based on this method. The finishing surface is a key point in obtaining the data, since polished surfaces allow the perfect coupling of the transducers, favoring the performance of the test in an appropriate manner. The data indicate unweathered rocks or absence of fractures in the analyzed monuments.

scholarly journals Properties of the Ignimbrites in the Architecture of the Historical Center of Arequipa, Peru

2021 ◽  
Vol 11 (22) ◽  
pp. 10571
Author(s):  
Rosa Bustamante ◽  
Patricia Vazquez ◽  
Nicanor Prendes
Keyword(s):  
Mechanical Behavior ◽  
Water Absorption ◽  
Pulse Velocity ◽  
High Porosity ◽  
Architectural Heritage ◽  
Non Linear ◽  
Historical Center ◽  
Very High ◽  
Ultrasound Pulse ◽  
Selection Of

The petrographic and petrophysical characteristics of three varieties of ignimbrites used in the architectural heritage of Arequipa (southwest Peru) are analyzed. The modal classification QAFP and TAS diagram discriminate their dacitic nature. Mercury injection porometry revealed very high porosity: 46.5% for white and beige ignimbrites, and 35.5% for the pink variety. Ignimbrites contain intrusions of vulcanodetrital fragments and vacuoles that influence their predominantly non-linear mechanical behavior. The results of water absorption by capillarity (C) and ultrasound pulse velocity (UPV) demonstrate a slight anisotropy for the beige variety and near isotropy for white and pink ignimbrites, which justify the randomness of the application of the ashlars in the masonry and in the selection of the faces to carve. Surfaces with hollows in the white and beige ignimbrites are the result of the erosion of the acicular pumice that fills the vacuoles.

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