A Combination of Acoustic Measurements Cementations To Evaluate (original) (raw)
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Cement Evaluation Tool: A New Approach to Cement Evaluation
Journal of Petroleum Technology, 1982
Summary A new generation of cement and casing evaluation tools is being introduced with construction permitting detailed examination of cement behind casing. Classical cement bond logging systems measure amplitude or attenuation of plan waves propagating axially along the casing. The design described in this paper exploits the principle of casing thickness resonance to overcome previous tool limitations. Applications and results from field tests illustrate the advantages of this approach. Cement bond logging achieves its greatest utility when it provides the production engineer with precise indications of cement strength and distribution around the casing. Zone isolation is of critical importance in production. Previous logging systems have yielded measures of cement bond that were circumferential averages of cement quality. These were difficult to interpret. Additionally, they were sensitive to the degree of shear coupling between pipe, cement, and formation and thus were affected ...
Ultrasonic assessment of early-age changes in the material properties of cementitious materials
Materials and Structures, 2007
After casting, cementitious materials exhibit a continuous change in the mechanical properties with time due to a chemical reaction known as hydration. In addition, these materials also exhibit a change in state, from a fluid to a solid, in the first few hours. Conventionally, changes in the material properties are obtained by monitoring the visco-elastic moduli with time before setting and the increase in the elastic material properties of the solid cementitious material, after setting. An ultrasonic test setup and the data analysis procedures, which provide for continuous monitoring of the hydrating cementitious materials from a very early age through setting are presented in this paper. The test procedures for obtaining the ultrasonic test data and the inversion subroutines for assessing the material properties of the cementitious material at different stages of hydration are discussed. The experimental test results obtained from mortar mixtures of varying compositions are presented. The observed experimental trends are explained considering wave propagation in viscoelastic materials. There is a two-stage increase in the value of shear modulus of mortar with time. Experimental evidence suggests that initially there is a larger relative increase in the viscous component of the shear
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MATEC Web of Conferences, 2017
The paper is devoted to investigation mechanism of cement mixture setting and stiffening. Method for registration of the acoustic oscillations induced during the heterophase transitions executing in liquid medium was proposed (method of acoustic emission (AE)). Using of conical vessel serving as a resonator allows the amplification of registered acoustic signal and provides high sensitivity of the registration. The experimental results show that the using of AE-method allows remote monitoring of the dynamics of concrete mixtures condition during setting. Therefore, this method can be successfully applied in building as a nondestructive method for determining the start and end of the solidification of the cement solution.
Monitoring the setting behavior of cementitious materials using one-sided ultrasonic measurements
Cement and Concrete Research, 2005
Cementitious materials are transformed from a fluid to a solid state due to a chemical reaction known as hydration. These cementitious materials exhibit a continuous change in the mechanical properties with time; there is a steady increase in the stiffness after setting. An ultrasonic test setup and the data analysis procedure, which provide for continuous monitoring of the hydrating cementitious materials from a very early age, have recently been developed. The test procedure for obtaining the ultrasonic test data from cementitious material at different stages of hydration and the theoretical analysis, which allows interpreting the ultrasonic response in terms of the changes in the acoustic shear impedance of the hydrating cementitious material, are presented in this paper. Experimental test results obtained from mortar mixtures of known composition are presented. It is shown that the initial and final setting times correspond approximately with the occurrence of distinctive features in the ultrasonic response. D
Application of Ultrasonic Measurements for Determination of Setting and Hardening in Cement Paste
Journal of Civil Engineering and Architecture, 2011
Concrete setting and hardening processes are the most critical phases during construction works, influencing properties of a concrete structure. The initial set is important as it provides an estimate when concrete has reached a point that it can no longer be vibrated without damaging concrete. The point at which final set occurs is important since it provides an estimate when the development of concrete strength and stiffness starts. In this study, experimental work is performed under laboratory conditions to indentify the setting time of cement paste using ultrasonic waves. Correlation between the ultrasonic wave parameters (speed, amplitude and energy) passing through the fresh cement paste and setting time determined using the Vicat test method is analyzed. A method of acoustic emission is also used and acoustic signals recorded in cement paste during hydration are presented.
Cement and Concrete Research, 2009
This paper presents the comparison between ultrasonic wave transmission (USWT) method and ultrasonic wave reflection (USWR) method in their ability to monitor the setting process of cement pastes. The velocity of ultrasonic longitudinal waves and shear wave reflection coefficient were measured simultaneously on cement pastes with different hydration kinetics. Even though both methods are able to reliably monitor the hydration process and formation of structure of an arbitrary cement paste, they monitor the setting process in different ways. The relationship between the velocity of longitudinal waves and shear wave reflection coefficient can be simplified into three characteristic phases and the end of the first phase can be used to define the beginning of the setting process of cement paste.
Non-destructive evaluation of eco-friendly cementitious materials by ultrasound
2016
Ultrasonic methods have been developed in the past to study properties of cement based materials in the fresh and hardening state. However, most of the methods only consider a certain type of ultrasonic waves. To derive elastic parameters of fresh concrete like the Poisson's ratio and elastic modules it is required to obtain shear waves as well as compressional waves. It is certainly much more difficult to establish a setup to transmit and record shear waves in a way that the onset of these slower waves (compared to compressional waves) can be detected as clear as necessary to calculate shear wave velocity values with the required accuracy. A test setup for testing cement paste with different ultrasonic waves is presented. Tests have been conducted that show reasonable ultrasonic compressional and shear wave transmission right after mixing. Thus ultrasound is found to be suited for the characterisation of paste mixtures and the determination of changes in the rheological properties already before setting. Test results from different cementitious mixes with a special focus on eco-pastes are presented. These eco-pastes show optimized packing density (using micro and eco fillers as replacement of Portland cement clinker).