scholarly journals The relationship between the compressive strength and ultrasonic pulse velocity concrete with fibers exposed to high temperatures

2018 ◽  
Vol 3 (1) ◽  
pp. 31
Author(s):  
Belaribi Hassiba ◽  
Mellas Mekki ◽  
Rahmani Fraid
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Velocity ◽  
High Temperatures ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Ratio ◽  
Compressive Strength Of Concrete ◽  
The Relationship ◽  
The Waves

The paper analyses the effects of high temperatures on the concrete residual strength using ultrasonic velocity (UPV). An experimental investigation was conducted to study the relationship between UPV residual data and compressive strength of concrete with different mixture proportions, cubic specimens with water-cement ratio of 0.35. They were heated in an electric furnace at temperatures ranging from 200°C to 600°C. In this experiment a comparison was made between the four groups which include two types of fibers steel 0,19%, 0,25% and 0,5%, polypropylene: 0,05%, 0,11% 0,16 % by volume. Cube specimens were tested in order to determine ultrasonic velocity. The compressive strength was tested too. According to the results, relations were established between ultrasonic velocity in the specimens and the compressive strength at different temperature and the range of the velocity of the waves were also determined for this kind of concrete. Result of the test showed that UPV test can be successfully used in order to verify the consistency of structures damaged by fire.

scholarly journals Using Ultrasonic Pulse Velocity Test to Assess the Effect of Water-Cement Ratio on the Compressive Strength of Concrete

2019 ◽  
Vol 25 (5) ◽  
pp. 79-86 ◽  
Author(s):  
Ziwar Zebari
Keyword(s):  
Compressive Strength ◽  
Material Science ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Ratio ◽  
Water Cement Ratio ◽  
Effect Of Water ◽  
Strength Tests ◽  
Compressive Strength Of Concrete

This study aims to find the effect of water-cement ratio on the compressive strength of concrete by using ultrasonic pulse velocity test (UPVT). Over 230 standard cube specimens were used in this study, with dimensions of 150mm, and concrete cubes were cured in water at 20 °C. Also, the specimens used in the study were made of concrete with varied water-cement ratio contents from 0.48 to 0.59. The specimens were taken from Diyarbakir-Turkey concrete centers and tested at the structure and material science lab, civil engineering, faculty of engineering from Dicle University.  The UPV measurement and compressive strength tests were carried out at the concrete age of 28 days. Their UPV and compressive strength ranged between (3.89-4.66km/s) and (17.74-40.56MPa) respectively. The experimental results showed that although the UPV and the compressive strength of concrete are related, also, the UPV and compressive strength have a relation with the rate of the water-cement ratio of concrete.  

scholarly journals Using Support Vector Machine to Improve Ultrasonic Pulse Velocity Test for Concrete

2018 ◽  
Vol 207 ◽  
pp. 01001
Author(s):  
Tu Quynh Loan Ngo ◽  
Yu-Ren Wang
Keyword(s):  
Compressive Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Support Vector ◽  
Non Destructive Testing ◽  
Testing Methods ◽  
Destructive Testing ◽  
Compressive Strength Of Concrete ◽  
Non Destructive

In the construction industry, to evaluate the compressive strength of concrete, destructive and non-destructive testing methods are used. Non-destructive testing methods are preferable due to the fact that those methods do not destroy concrete samples. However, they usually give larger percentage of error than using destructive tests. Among the non-destructive testing methods, the ultrasonic pulse velocity test is the popular one because it is economic and very simple in operation. Using the ultrasonic pulse velocity test gives 20% MAPE more than using destructive tests. This paper aims to improve the ultrasonic pulse velocity test results in estimating the compressive strength of concrete using the help of artificial intelligent. To establish a better prediction model for the ultrasonic pulse velocity test, data collected from 312 cylinder of concrete samples are used to develop and validate the model. The research results provide valuable information when using the ultrasonic pulse velocity tests to the inputs data in addition with support vector machine by learning algorithms, and the actual compressive strengths are set as the target output data to train the model. The results show that both MAPEs for the linear and nonlinear regression models are 11.17% and 17.66% respectively. The MAPE for the support vector machine models is 11.02%. These research results can provide valuable information when using the ultrasonic pulse velocity test to estimate the compressive strength of concrete.

scholarly journals Empirical Investigation on Compressive Strength of Geopolymer and Conventional Concretes by Nondestructive Method

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
B. Ravali ◽  
K. Bala Gopi Krishna ◽  
D. Ravi Kanth ◽  
K. J. Brahma Chari ◽  
S. Venkatesa Prabhu ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Nondestructive Method ◽  
Geopolymer Concrete ◽  
River Sand ◽  
Rebound Hammer ◽  
Compressive Strength Of Concrete

Need of construction is increasing due to increase in population growth rate. The geopolymer concrete is eco-friendly than ordinary concrete. Current experimental investigation was conducted on ordinary and geopolymer concrete using nondestructive testing (NDT) tests like ultrasonic pulse velocity (UPV) test and rebound hammer (RH) test. Cube specimens of dimensions 150 mm × 150 mm × 150 mm are used to conduct these tests at 7, 14, and 28 days. Proportions considered for concrete are cement-fly ash-river sand (100-0-100% and 60-40-100%), cement-fly ash-robo sand (100-0-100% and 60-40-100%) whereas geopolymer concrete fly ash-metakaolin is taken in proportions of 100-0%, 60-40%, and 50-50%. Alkaline activators (sodium hydroxide and sodium silicate with molarity 12M) were used in preparing geopolymer concrete. The major objective of the current study is to obtain relation between compressive strength of concrete and UPV values.

scholarly journals Transport Properties and Resistance Improvement of Ultra-High Performance Concrete (UHPC) after Exposure to Elevated Temperatures

Buildings ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 416
Author(s):  
Yunfeng Qian ◽  
Dingyi Yang ◽  
Yanghao Xia ◽  
Han Gao ◽  
Zhiming Ma
Keyword(s):  
Compressive Strength ◽  
Transport Properties ◽  
High Temperatures ◽  
High Performance ◽  
High Performance Concrete ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Capillary Absorption ◽  
Self Healing

Ultra-high performance concrete (UHPC) has a high self-healing capacity and is prone to bursting after exposure to high temperatures due to its characteristics. This work evaluates the damage and improvement of UHPC with coarse aggregates through mechanical properties (compressive strength and ultrasonic pulse velocity), transport properties (water absorption and a chloride diffusion test), and micro-properties such as X-ray diffraction (XRD), Mercury intrusion porosimetry (MIP), and Scanning electronic microscopy (SEM). The result demonstrates that polypropylene (PP) fibers are more suitable for high temperature tests than polyacrylonitrile (PAN) fibers. The result shows that 400 °C is the critical temperature point. With the increase in temperature, the hydration becomes significant, and the internal material phase changes accordingly. Although the total pore volume increased, the percentage of various types of pores was optimized within 400 °C. The mass loss gradually increased and the ultrasonic pulse velocity gradually decreased. While the compressive strength first increased and then decreased, and the increase occurred within 25–400 °C. As for the transport properties, the chloride migration coefficient and capillary absorption coefficient both increased dramatically due to the higher sensitivity to temperature changes. The results of the property improvement test showed that at temperatures above 800 °C, the compressive strength recovered by more than 65% and the ultrasonic pulse velocity recovered by more than 75%. In terms of transport properties, compared to the results before self-healing, the chloride migration coefficient decreased by up to 59%, compared with 89% for the capillary absorption coefficient, after self-healing at 800 °C. With respect to the enhancement effect after exposure to high temperatures, the environment of a 5% Na2SO4 solution was not as good as the clean water environment. The corresponding changes in microstructure during the high temperatures and the self-healing process can explain the change in the pattern of macroscopic properties more precisely.

Effect of Elevated Temperature on the Strength and Ultrasonic Pulse Velocity of Glass Fiber and Nano-Clay Concrete

2010 ◽  
Vol 163-167 ◽  
pp. 1532-1539 ◽  
Author(s):  
Chung Ming Ho ◽  
Wei Tsung Tsai
Keyword(s):  
Compressive Strength ◽  
Glass Fiber ◽  
Residual Strength ◽  
Elevated Temperatures ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Nano Clay ◽  
Compressive Strength Of Concrete ◽  
Temperature Exposure

The objectives of this paper are to find the strength and ultrasonic pulse velocity (UPV) of concrete adding admixtures by glass fiber and nano-clay. Residual strength and residual UPV of concrete specimens subjected to elevated temperatures are investigated. Experiment results showed that adding glass fiber and nano-clay would be beneficial for the later-age compressive strength of concrete. Adding nano-clay could considerably increase the flexural and split strength and the toughness of concrete. It is revealed that adding nano-clay could significantly maintain residual compressive and split strength of specimens after high temperature exposure. Regression analysis results revealed that the residual strength and residual UPV of concrete specimens had a high relevance after elevated temperatures exposure.

scholarly journals Empirical Formula for Assessment Concrete Compressive Strength by Using Ultrasonic Pulse Velocity

2018 ◽  
Vol 7 (4.20) ◽  
pp. 113
Author(s):  
Hameed Shakir Al-Aasm
Keyword(s):  
Compressive Strength ◽  
Empirical Formula ◽  
Salt Content ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Fine Aggregate ◽  
Acceptable Error ◽  
Statistical Program ◽  
Compressive Strength Of Concrete

Statistical practical program was carried out to establish a fairly accurate empirical formula between compressive strength of concrete and ultrasonic pulse velocity. The work has a strong empirical base, but it is firmly governed by theory. In concrete, the compressive strength of concrete is related to the type, proportion and physical properties of aggregate but it is well known to be intensely affected by the properties of the cement paste, which relate, mainly, to the w/c ratio. The other variables such as age and density of concrete, salt content in fine aggregate and curing method have a relatively little effect on compressive strength of concrete. Therefore, the program involves field testing of reinforced concrete members that their w/c ratio and cube uniaxial compressive strength are known. The results were used as input data in statistical program (SPSS) to develop an empirical formula between the compressive strength of concrete and ultrasonic pulse velocity. The proposed formula was confirmed by the results of previous experiments. Although the relationship between the compressive strength of concrete and ultrasonic pulse velocity physically indirect, the statistical program revealed that the pulse velocity test could be used with acceptable error in evaluating the compressive strength of concrete.  

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