Ultrasonic Testing of Lightweight Fine Aggregate Concrete in Time and Frequency Domains

2013 ◽  
Vol 357-360 ◽  
pp. 655-658
Author(s):  
Jee Sang Kim ◽  
Kyung Suk Yoo
Keyword(s):  
Frequency Domain ◽  
Time Domain ◽  
Ultrasonic Pulse Velocity ◽  
Peak Frequency ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Fine Aggregate ◽  
Aggregate Concrete ◽  
Future Performance ◽  
Significant Difference

Non-destructive techniques (NDT) have been used to assess the condition of existing concrete structures, to predict future performance, and to monitor the conditions of repaired systems and so on. One of the widely known NDT is the ultrasonic pulse velocity (USPV) method, which determines the travel time of the ultrasonic pulse through the tested material. Most studies were focused on the results expressed in time domain. However, the signal of ultrasonic pulse in time domain can be transformed into frequency domain, through Fast Fourier Transform (FFT). This paper shows a comparison of changes in the pulse velocity and frequency domain signals of concrete for various load histories using lightweight fine aggregates. The results demonstrate that the signals in frequency domain of ultrasonic pulse of lightweight fine aggregate concrete does not show any significant difference comparing with those of normal concrete. The reduction trend of peak frequency was found to be more influenced by the stress levels rather than the ultrasonic pulse velocity.

Recycling of Waste Limestone as Fine Aggregate for Conventional and Green Concretes

2018 ◽  
Vol 928 ◽  
pp. 257-262 ◽  
Author(s):  
Trong Phuoc Huynh ◽  
Chao Lung Hwang ◽  
Si Huy Ngo
Keyword(s):  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Concrete Mixture ◽  
Engineering Properties ◽  
Fine Aggregate ◽  
Normal Concrete ◽  
Design Algorithm ◽  
Green Concrete ◽  
Concrete Mixtures

This paper presents the results of the experimental works to investigate the use of waste limestone from water treatment industry as fine aggregate in green concrete. Two concrete mixtures with a constant water-to-binder ratio of 0.3 were prepared for this investigation, in which, the normal concrete mixture was designed following the guidelines of ACI 211 standard, while the green concrete mixture was designed using densified mixture design algorithm (DMDA) technology. For comparison, both types of concrete samples were subjected to the same test program, including fresh properties, compressive strength, strength efficiency of cement, drying shrinkage, electrical surface resistivity, ultrasonic pulse velocity, and thermal conductivity. Test results indicate that both concrete mixtures showed the excellent workability due to the round-shape of waste limestone aggregate and the use of superplasticizer. In addition, the green concrete mixture exhibited a better performance in terms of engineering properties and durability in comparison with the normal concrete mixture. The results of the present study further support the recycling and reuse of waste limestone as fine aggregate in the production of green concrete.

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.

scholarly journals Effect of Stone Dust on the Mechanical and Microstructural Properties of Opc based Concrete Subjected to Acid Exposure

2019 ◽  
Vol 8 (3) ◽  
pp. 7488-7492 ◽  
Keyword(s):  
Concrete Strength ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Acid Exposure ◽  
Fine Aggregate ◽  
Cell Potential ◽  
Stone Dust ◽  
Different Types ◽  
Mechanical And Microstructural Properties

A separate approach of sustainable development is to make the structures durable. More durable structures need to be replaced less frequently and will reduce the need for cement. Such increase in durability can be achieved by choosing appropriate mix designs and selecting suitable aggregates and admixtures. In this experiment sand (fine aggregate) is partially replaced by stone dust to make the concrete mix sustainable in nature. This study also investigates the durability of different types of concrete in acid exposure. Cube compressive strengths of different mixes have been compared to see how the concrete strength differs from original mixes. In addition different types of non-destructive tests such as ultrasonic pulse velocity test, rebound hammer test and half-cell potential tests have also been performed on the concrete samples for better analysis of their strength and durability characteristics. Specimens were analysed through the Scanning Electron Microscope to understand the microstructural changes of concrete samples. Energy dispersion X-ray analysis was also done to understand the changes in the nature of the hydration products of some specimen.

An Ultrasonic Pulse Velocity Test on Fly-Ash Based Geopolymer Concrete in Frequency Domains

2014 ◽  
Vol 700 ◽  
pp. 310-313 ◽  
Author(s):  
Jee Sang Kim ◽  
Tae Hong Kim
Keyword(s):  
Compressive Strength ◽  
Construction Material ◽  
High Strength ◽  
Ultrasonic Pulse Velocity ◽  
Peak Frequency ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
P Wave ◽  
Geopolymer Concrete ◽  
Existing Structures

The Non-Destructive Test techniques on concrete, which can assess the properties of materials without damages, have been developed as the deteriorations of existing structures increase. Among them, the ultrasonic pulse velocity (USPV) method is widely used because it can investigate the states of one material for a long time and repeatedly. However, there have been few researches on the NDT application to geopolymer concrete which is environment friendly construction material without any cement. This paper investigates the variations of ultrasonic pulse velocity and peak frequency of geopolymer concrete under monotonically increasing loads to assess the material conditions with various compressive strength levels by measuring P-wave signals. The pulse velocities and peak frequencies were higher in high strength geopolymer concrete specimens. There are not explicit relations between strength levels and peak frequencies but the peak frequencies are strongly influenced by the applied stress levels. In addition, a predicting equation for compressive strength of geopolymer concrete is derived based on experimental data in similar form for normal concrete.

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.  

scholarly journals Characteristics of Preplaced Aggregate Concrete Fabricated with Alkali-Activated Slag/Fly Ash Cements

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 591
Author(s):  
Salman Siddique ◽  
Hyeju Kim ◽  
Hyemin Son ◽  
Jeong Gook Jang
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Water Absorption ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Cement Grout ◽  
Aggregate Concrete ◽  
Alkali Activated ◽  
Alkali Activated Cement

This study assesses the characteristics of preplaced aggregate concrete prepared with alkali-activated cement grout as an adhesive binder. Various binary blends of slag and fly ash without fine aggregate as a filler material were considered along with different solution-to-solid ratios. The properties of fresh and hardened grout along with the properties of hardened preplaced concrete were investigated, as were the compressive strength, ultrasonic pulse velocity, density, water absorption and total voids of the preplaced concrete. The results indicated that alkali-activated cement grout has better flowability characteristics and compressive strength than conventional cement grout. As a result, the mechanical performance of the preplaced aggregate concrete was significantly improved. The results pertaining to the water absorption and porosity revealed that the alkali-activated preplaced aggregate concrete is more resistant to water permeation. The filling capacity based on the ultrasonic pulse velocity value is discussed to comment on the wrapping ability of alkali-activated cement grout.

scholarly journals Eco-Friendly Chopped Tire Rubber as Reinforcements in Fly Ash Geopolymer Concrete

2020 ◽  
Keyword(s):  
Fly Ash ◽  
Mechanical Performance ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Industrial Wastes ◽  
Fine Aggregate ◽  
Geopolymer Concrete ◽  
Tire Rubber ◽  
Naoh Solution

<p>One of the major challenges faced by researchers is to recycle industrial wastes in a manner that reduces their environmental impact in nature. An experimental study was carried out to determine the suitability of using chopped tire rubber as reinforcements in green and sustainable geopolymer concrete, with the purpose of using them as nonstructural products. The geopolymer mixture was made by mixing of fly ash powder, fine aggregate, and Superplasticizer in Na2SiO3/NaOH solution. Mixtures were divided into four different groups, with constant water to fly ash ratio of 0.12 and alkaline dosage of 45% by weight of fly ash, based on the recycled chopped tire rubber (CTR) content: 0, 10, 20, and 30% by volume of fine aggregate with two maximum sizes (2 and 4mm). Hardened properties of resulted geopolymer like compressive strength, density; and ultrasonic pulse velocity were examined at 28d. Besides that, X-Ray diffractometer and Scanning Electron Microscope were used in order to observe the microstructure of the resulted geopolymer concrete. In view of the consequences for this study, it is preferable to replace no more than 10% of fine aggregate in geopolymer concrete by CTR. In addition, according to SEM photographs, increasing the CTR content more voids will be pronounced and thus, decreasing the mechanical performance.</p>

scholarly journals Performance Degradation and Microscopic Analysis of Lightweight Aggregate Concrete after Exposure to High Temperature

Materials ◽  
2020 ◽  
Vol 13 (7) ◽  
pp. 1566 ◽  
Author(s):  
Weijing Yao ◽  
Jianyong Pang ◽  
Yushan Liu
Keyword(s):  
Compressive Strength ◽  
High Temperature ◽  
Lightweight Aggregate ◽  
Strength Loss ◽  
Ultrasonic Pulse Velocity ◽  
Ultrasonic Pulse ◽  
Pulse Velocity ◽  
Lightweight Aggregate Concrete ◽  
Aggregate Concrete ◽  
Damage Degree

This study analyses the deterioration of mechanical properties in lightweight concrete after exposure to room temperature (20 °C) and high temperature, i.e., up to 1000 °C, including changes in visual appearance, loss of mass, and compressive strength. All-lightweight shale ceramsite aggregate concrete (ALWAC) and semi-lightweight shale ceramsite aggregate concrete (SLWAC) are prepared using an absolute volume method to analyse the relationships between relative ultrasonic pulse velocity, loss rate of compressive strength, damage degree, and temperature levels. Our results show that, under high temperature, the lightweight aggregate ceramsite concrete performs better compared to normal concrete. After exposure to 1000 °C, the ALWAC shows a strength loss of no more than 80%, while the normal concrete loses its bearing capacity, with a similar strength loss as the SLWAC. Furthermore, the relative ultrasonic pulse velocity and damage degree are used to evaluate the effects of high temperature on the concretes, including the voids and cracks on the surface and inside of the specimens, which induces the deterioration of mechanical properties and contributes to the thermal decomposition of the cementing system and the loss of cohesion at the aggregate interface. Based on internal structure analyses, the results from this study confirm that the lightweight aggregate concrete shows a high residual compressive strength after exposure to the high temperature.

Effect of All-Component Recycled GFRP on Physical-Mechanical Properties and Microstructures of Concrete

2021 ◽  
Vol 1036 ◽  
pp. 402-418
Author(s):  
Bo Yu Zhou ◽  
Mo Zhang ◽  
Guo Wei Ma
Keyword(s):  
Setting Time ◽  
Ultrasonic Pulse Velocity ◽  
Cementitious Materials ◽  
Ultrasonic Pulse ◽  
Mechanical Tests ◽  
Pulse Velocity ◽  
Depth Of Field ◽  
Fine Aggregate ◽  
Reinforced Plastics ◽  
Splitting Strength

Large inventory and non-degradability made waste glass fiber reinforced plastics (GFRP) a heavy burden to environment. They are increasingly reclaimed through mechanical crushing and used as aggregate replacement in concrete. However, reuse of all-component recycled GFRP (rGFRP) was still limited due to the inconsistent influences of powder and fiber on cementitious materials. In this study, mortar and concrete with two different gradations of all-component rGFRP at 10 wt%, 20 wt% and 30 wt% were investigated with mechanical tests, ultrasonic pulse velocity inspection, Depth-of-Field optical microscopy, Scanning Electron Microscopy (SEM) and micro-CT. It revealed that the splitting strength of cement mortar was significantly increased while 10 wt% of rGFRP was added, whereas the compressive and flexural strength were barely affected. For concrete, the initial and final setting time were prolonged by the addition of 30 wt% rGFRP up to 93.8% and 124.3%, respectively. The mechanical strength of concrete increased with rGFRP content firstly, and then decreased, due to the reduced dispersity of rGFRP and compactness of mortar. When 10 wt% of rGFRP was added, the 28-day compressive, flexural and splitting strength of concrete were optimized to 25.8 MPa, 4.25 MPa and 3.02 MPa, respectively. The failure pattern analysis indicated that rGFRP can restrain crack propagation, reduce crack width and improve the integrity of fractured concrete. The results suggested the potential feasibility of rGFRP as fine aggregate replacement, and provided solid experimental references for practically reusing rGFRP in cementitious materials.

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