scholarly journals Tensile Strength Modeling of Limestone Rocks in Sulaymaniyah City, Iraq Using Simple Tests

2019 ◽  
Vol 9 (2) ◽  
pp. 149-155
Author(s):  
Diyari A. Mohammed ◽  
Younis M. Alshkane

Tensile strength of rocks is one of the mechanical properties of intact rock that is a significant parameter for designing geotechnical structures includes dam foundations and tunnels. The tensile strength can be determined indirectly using Brazilian indirect test procedure that is mentioned in the International Society for Rock Mechanics suggested methods. The availability of rock samples is needed to perform the Brazilian indirect test so as to determine their tensile strength which is expensive, time-consuming, and cost-effective especially for weak quality rock formations. Therefore, non-destructive methods for predicting the tensile strength of the rock are crucially needed during the poor quality of rock samples. Non-destructive tests can be correlated with indirect tests to predict Brazilian tensile strength (BTS) of rocks such as ultrasonic pulse velocity and Schmidt hammer. These methods are simple and can be easily conducted in the field. This study is focused on the tensile strength of limestone rocks for three main formations of Sulaymaniyah city. The samples were obtained using a standard core barrel. Statistical analysis including minimum, maximum, mean, standard deviation, variance, and coefficient of variance for the results was conducted. Single and multiple correlations between BTS and each of ultrasonic pulse velocity and Schmidt hammer rebound number of limestone rocks were created. Reasonable empirical equations were developed to predict the tensile strength of limestone rocks. In addition, the point load strength index was correlated with BTS. The comparison between proposed equations from this study and equation from the literature was also investigated.

2018 ◽  
Vol 219 ◽  
pp. 03003
Author(s):  
Richard Dvořák ◽  
Zdeněk Chobola ◽  
Ivo Kusák

The paper is focused on non-destructive measurement of high temperature degraded concrete test specimens of three mixtures different by the use of coarse aggregate. Testing is done by ultrasonicpulse velocitymethod and Impact-Echo method. Non-destructive results are compared with destructive tests. Ultrasonic pulse velocity, dominant resonance frequency and acoustic impedance are discussed and compared with changes in density, cubic compressive strength, and tensile strength of concrete. The paper suggests possible assessment of degraded concrete by the change in acoustic impedance dependent on residual tensile strength.


2021 ◽  
Author(s):  
Asad Kamran ◽  
Liaqat Ali ◽  
Waqas Ahmed ◽  
Sobia Zoreen ◽  
Shah Jehan

Abstract This study investigated the aggregate suitability and geo-chemical characteristics of limestone (LS) for construction industries. The results of aggregate parameters for different applications revealed that specific gravity (SG = 2.6), water absorption (WA = 0.47%), bulk density (BD = 1.58 g/cm3), flakiness index (FI = 16.8%), elongation index (EI = 16.39%), soundness (S = 1.6%), aggregate impact value (AIV = 14%), Los Angles Abrasion value (LAAV = 23.51%), clay lumps (CL = 0.35%), uniaxial compressive strength (UCS = 86.7 MPa), point load test (PLT = 5.18 MPa), ultrasonic pulse velocity (UPV = 5290 m/s) and Schmidt hammer rebound test (SHRT = 49 N) are in accordance with ASTM, ISRM and BSI. Petrographically, the LS is dominantly composed of ooids, peloids, bioclasts and calcite (CaCO3) with trace concentration of the dolomite. Geochemical results (n = 18) indicated that the LS is dominantly made up of calcite (95.81%); while on average it is composed of 52.08 wt.% CaO, 1.13 wt. % SiO2, 0.66 wt. %, MgO, 0.80 wt. % Al2O3, 0.76 wt. % Fe2O3 and LOI were recorded as 42.13 wt. %. Whereas, P2O5, TiO2, MnO, K2O and Na2O are found in trace amount. Regression analysis demonstrates that the empirical correlation equation for estimating uniaxial compressive strength with ultrasonic pulse velocity is more reliable than Schmidt hammer rebound test and point load test. The findings of this study strongly suggest LS of the area has a great potential as a raw material in construction industries.


2021 ◽  
Vol 318 ◽  
pp. 03004
Author(s):  
AbdulMuttalib I. Said ◽  
Baqer Abdul Hussein Ali

This paper has carried out an experimental program to establish a relatively accurate relation between the ultrasonic pulse velocity (UPV) and the concrete compressive strength. The program involved testing concrete cubes of (100) mm and prisms of (100×100×300) cast with specified test variables. The samples are tested by using ultrasonic test equipment with two methods, direct ultrasonic pulse (DUPV) and surface (indirect) ultrasonic pulse (SUPV) for each sample. The obtained results were used as input data in the statistical program (SPSS) to predict the best equation representing the relation between the compressive strength and the ultrasonic pulse velocity. In this research 383 specimens were tested, and an exponential equation is proposed for this purpose. The statistical program has been used to prove which type of UPV is more suitable, the (SUPV) test or the (DUPV) test, to represent the relation between the ultrasonic pulse velocity and the concrete compressive strength. In this paper, the effect of salt content on the connection between the ultrasonic pulse velocity and the concrete compressive strength has also been studied.


2011 ◽  
Vol 243-249 ◽  
pp. 165-169 ◽  
Author(s):  
Iqbal Khan Mohammad

Nondestructive testing (NDT) is a technique to determine the integrity of a material, component or structure. The commonly NDT methods used for the concrete are dynamic modulus of elasticity and ultrasonic pulse velocity. The dynamic modulus of elasticity of concrete is related to the structural stiffness and deformation process of concrete structures, and is highly sensitive to the cracking. The velocity of ultrasonic pulses travelling in a solid material depends on the density and elastic properties of that material. Non-destructive testing namely, dynamic modulus of elasticity and ultrasonic pulse velocity was measured for high strength concrete incorporating cementitious composites. Results of dynamic modulus of elasticity and ultrasonic pulse velocity are reported and their relationships with compressive strength are presented. It has been found that NDT is reasonably good and reliable tool to measure the property of concrete which also gives the fair indication of the compressive strength development.


Coatings ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 83 ◽  
Author(s):  
Kamil Krzywiński ◽  
Łukasz Sadowski ◽  
Jacek Szymanowski ◽  
Andrzej Żak ◽  
Magdalena Piechówka-Mielnik

This article presents studies that were performed in order to improve the subsurface properties of horizontally-formed cementitious composites using tin(II) fluoride nanoparticles. The main aim of the study was to solve the problem of the decrease in subsurface properties caused by mortar bleeding and the segregation of the aggregate along the height of the overlay. The article also aims to highlight the patch grabbing difficulties that occur during the process of forming horizontally-formed cementitious composites. Four specimens were analyzed: one reference sample and three samples modified with the addition of 0.5, 1.0, and 1.5% of tin(II) fluoride nanoparticles in relation to the cement mass. To analyze the mechanical properties of the specimens, non-destructive (ultrasonic pulse velocity) and destructive tests (flexural tensile strength, compressive strength, abrasion resistance, pull-off strength) were performed. It was indicated that due to the addition of the tin(II) fluoride, it was possible to enhance the subsurface tensile strength and abrasion resistance of the tested cementitious composites. To confirm the obtained macroscopic results, the porosity of the subsurface was measured using SEM. It was also shown that the addition of the tin(II) fluoride nanoparticles did not reduce its flexural and compressive strength. The results show that horizontally-formed cementitious composites with the addition of 1.0% of tin(II) fluoride nanoparticles in relation to the cement mass obtained the most effective mechanical performance, especially with regard to subsurface properties.


2017 ◽  
Vol 902 ◽  
pp. 9-13
Author(s):  
Rosalía Ruiz Ruiz ◽  
Elia Mercedes Alonso Guzmán ◽  
Wilfrido Martínez Molina ◽  
Hugo Luis Chávez García ◽  
Judith Alejandra Velázquez Perez

Cement industry is responsible of 5-7% of CO2 emissions to the atmosphere. This is preoccupant because this is one of the greenhouse effect gases which cause global warming. Pozzolanic material incorporation in cement mortars elaboration represents a good alternative to partially substitute cement, since its chemical composition could contribute to improvement of its durability and mechanical characteristics. In this research, mortars with pozzolanic substitutions are evaluated through non-destructive tests as: capillary absorption, electrical resistivity, and ultrasonic pulse velocity to the age of 1000 days. The results suggested that the incorporation of pozzolanic material as partial substitutes of Portland cement increases the mortars properties mainly in substitutions of CBC 20%, PN 10, and 30%.


2018 ◽  
Vol 207 ◽  
pp. 01001
Author(s):  
Tu Quynh Loan Ngo ◽  
Yu-Ren Wang

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.


2020 ◽  
Vol 13 (2) ◽  
pp. 222-247 ◽  
Author(s):  
J. P. GODINHO ◽  
T. F. DE SOUZA JÚNIOR ◽  
M. H. F. MEDEIROS ◽  
M. S. A SILVA

Abstract The hydration process of Portland cement triggers reactions of stabilization of minerals from the contact of the clinker with water, which is the Hydrated Calcium Silicate (C-S-H), the Etringite (3CaO.Al2O3.3CaSO4.32H2O) and the Portlandite (Ca(OH)2). In order to understand the effects of the evolution of hydration in cement, it is possible to apply non-destructive tests. In this context, the objective of this work is to evaluate the influence of the type of cement, the curing age, of the format and humidity of the test specimens of concrete in the ultrasonic pulse velocity (UPV). In order to do that, 36 cylindrical test specimens (10 x 20 cm) and 9 cubic ones with 25 cm of edges, with mix proportion of 1:2,7:3,2 (cement/sand/gravel), water/cement ratio of 0.58 and three types of Portland cement (CP II-Z-32, CP IV-32 RS and CP V-ARI) were molded. With data obtained it was possible to correlate the increase of concrete strength along time (at ages of 7, 14, 28, 70 and 91 days) with the increase of the ultrasonic pulse velocity. Besides, it was possible to prove the direct influence of the concrete moisture and of the degree of hydration in the UPV. The shape of the test specimen generally had no influence on the results, except in the case of cement CP V ARI.


2021 ◽  
Vol 21 (6) ◽  
pp. 209-215
Author(s):  
Yunje Lee ◽  
Jaehun Ahn ◽  
Yungtak Oh ◽  
Jaegeon Lee

The expansion of impervious areas owing to urbanization has adverse effects on water circulation. The application of low-impact development techniques to solve these problems is gaining popularity. Among others, Permeable pavements are the most widely employed low-impact development techniques. In this study, the dynamic modulus and tensile strength of pervious polymer concrete pavement were evaluated before and after freezing-thawing cycles. A tensile strength test, performed to check the soundness of the pervious polymer concrete, yielded a tensile strength and tensile strength ratio of 0.66 to 0.96 MPa, and 72 to 83%, respectively. The ultrasonic pulse velocity was measured to determine the dynamic modulus according to the freezing-thawing cycles. When 300 freezing-thawing cycles were performed, the dynamic modulus was analyzed to drop to a level of 77~85% of the initial value. The standards for freezing and thawing tests of pervious concrete have not yet been established. It is necessary to develop test standards for freezing-thawing resistance of pervious concretes considering climate change.


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