scholarly journals Research on the size effect of roughness on rock uniaxial compressive strength and characteristic strength

2021 ◽  
Vol 28 (1) ◽  
pp. 613-627
Author(s):  
Gaojian Hu ◽  
Yu Li ◽  
Gang Ma
Keyword(s):  
Compressive Strength ◽  
Size Effect ◽  
Uniaxial Compressive Strength ◽  
Strain Curve ◽  
Characteristic Size ◽  
Roughness Coefficient ◽  
Joint Roughness ◽  
Characteristic Strength ◽  
Relationship Of ◽  
The Relationship

Abstract The joint roughness has an influence on the uniaxial compressive strength (UCS) and characteristic strength of the rock, but the relationship of the influence is yet to be obtained. In this article, the influence of the size of the rock with rough joints on the UCS and the influence of the size effect of roughness on the UCS are studied by establishing 11 sets of numerical simulation schemes, a total of 30 working conditions. The stress–strain curve law of rocks with different roughness and sizes is analyzed, and the relationship between UCS and the size of rock with rough joints, joint roughness coefficient (JRC), is respectively proposed. Mathematical models of rock characteristic size of UCS, characteristic strength of the rock, and JRC are established, respectively.

scholarly journals Size effect of parallel-joint spacing on uniaxial compressive strength of rock

PLoS ONE ◽  
2021 ◽  
Vol 16 (9) ◽  
pp. e0257245
Author(s):  
Gaojian Hu ◽  
Gang Ma
Keyword(s):  
Mathematical Model ◽  
Compressive Strength ◽  
Size Effect ◽  
Uniaxial Compressive Strength ◽  
Strength Characteristic ◽  
Characteristic Size ◽  
Stress Strain ◽  
Joint Spacing ◽  
The Relationship

The existence of parallel joints has an impact on the size effect of the uniaxial compressive strength of rock, but the relationship is yet to be obtained. In this paper, the influence of parallel-joint spacing on the size effect and characteristic size of rock uniaxial compressive strength is studied by establishing five types of parallel-joint-spacing simulation schemes. The influence of parallel-joint spacing on the size effect of rock uniaxial compressive strength is explored by analyzing the stress–strain curves of rocks with different parallel-joint spacings and rock sizes. The relationship between the uniaxial compressive strength and the size of the rock with parallel joints and its special mathematical model are obtained, and the particular form of the compressive-strength characteristic size and parallel-joint spacing is obtained.

scholarly journals Size Effect of the Number of Parallel Joints on Uniaxial Compressive Strength and Characteristic Strength

Minerals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 62
Author(s):  
Gaojian Hu ◽  
Gang Ma ◽  
Jie Liu ◽  
Kuan Qi
Keyword(s):  
Numerical Simulation ◽  
Compressive Strength ◽  
Size Effect ◽  
Mathematical Models ◽  
Numerical Simulations ◽  
Uniaxial Compressive Strength ◽  
Special Functions ◽  
Characteristic Size ◽  
Characteristic Strength ◽  
Rock Size

The number of parallel joints has an impact on the size effect of the uniaxial compressive strength and characteristic strength of a rock; however, the relationships between them are yet to be derived. We studied the influence of the number of joints and rock size on the uniaxial compressive strength of the rock. This study established ten numerical simulation programs using numerical simulations and the RFPA software. Stress–strain curves of different numbers of parallel joints and sizes of rocks were analyzed. Relationships between the uniaxial compressive strength and number of parallel joints and rock size were proposed, and their special functions were obtained. Mathematical models between rock characteristic size, rock characteristic strength and the number of parallel joints were established. Simulations of the verification program confirmed that these relationships are still applicable after the angle of parallel joints changes.

scholarly journals Mechanical Properties of Concrete Containing Liquefied Red Mud Subjected to Uniaxial Compression Loads

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 854 ◽  
Author(s):  
Gyeongcheol Choe ◽  
Sukpyo Kang ◽  
Hyeju Kang
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Red Mud ◽  
Construction Material ◽  
Strain Curve ◽  
Peak Strain ◽  
Cement Type ◽  
Mixing Method ◽  
Relationship Of ◽  
The Relationship

This study used liquefied red mud (RM) sludge, an aluminum industry by-product, as a construction material. Accordingly, various methods were examined that used the fabricated liquefied red mud (LRM) as an admixture for concrete, and the mechanical properties of concrete were then evaluated according to the cement type and the amount of LRM. The LRM mixing methods (replacement and addition) were compared, and the slump and compressive strengths of concrete were evaluated for each method. To examine the mechanical properties according to the cement type and the amount of LRM, two types of cement (ordinary Portland cement and slag cement (SC)) were used, and 20 and 40 wt% LRM (with respect to the cement weight) were added. The mechanical properties of the stress–strain curve (SSC), compressive strength, peak strain, and elastic modulus were quantified. When the slump and compressive strength of concrete were considered based on the experimental results, the addition LRM mixing method was recommended as the appropriate method for LRM. As the addition of LRM increased, the mechanical properties of concrete degraded. However, when SC was used, the mechanical properties did not significantly change when different amounts of LRM were added (up to 20%). In addition, the SSC of LRM concrete could be approximated based on the use of the relationship of the compressive strength and peak strain according to the cement type and the amount of LRM.

An evaluation of ECT sample height for small flute board grades and Box Manufacturer’s Certification compliance

TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK
Keyword(s):  
Compressive Strength ◽  
Compressive Load ◽  
Test Sample ◽  
Test Methods ◽  
Test Method ◽  
Initial Development ◽  
Sample Height ◽  
Relationship Of ◽  
The Relationship ◽  
Corrugated Fiberboard

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.

Size Effect on Mechanical Properties of LVL

2014 ◽  
Vol 887-888 ◽  
pp. 824-829
Author(s):  
Qing Fang Lv ◽  
Ji Hong Qin ◽  
Ran Zhu
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Compressive Strength ◽  
Size Effect ◽  
Tensile Test ◽  
Compression Test ◽  
Test Results ◽  
Laminated Veneer Lumber ◽  
Object Of Study ◽  
The Relationship

Laminated veneer lumber is taken as an object of study, and use LVL specimens of different sizes for compression test and tensile test. The goal of the experiment is to investigate the size effect on compressive strength and tensile strength as well as the influence of the secondary glued laminated face, which appears in the secondary molding processes. The results show that both compressive strength and tensile strength have the size effect apparently and the existence of the secondary glued laminated face lower the compressive strength of LVL specimens. Afterwards, the relationship between compressive strength and volume along with tensile strength and area are obtained by the test results.

Force Analysis and Modeling of Carbon Nanowires Operation in SEM

2011 ◽  
Vol 183-185 ◽  
pp. 1901-1906
Author(s):  
Wei Bin Rong ◽  
Dong Jie Li ◽  
Li Ning Sun ◽  
Jin Yu Wang
Keyword(s):  
Size Effect ◽  
Experimental System ◽  
Force Analysis ◽  
Simplified Models ◽  
Relationship Of ◽  
Influence Degree ◽  
The Relationship ◽  
Carbon Nanowires

Due to influence of size effect, the force properties in nanoscale are greatly different from those in macroscale and the traditional models of operation are becoming difficult to meet the development of nanoscale manipulation. To provide guiding theory for practical nano-manipulation, the nanoscale forces of contact and non-contact operation of nanowires are analyzed for nano-manipulation in SEM. The Vander Waals models among the probe, nanowire and substrate are modeled according to the force properties in nanoscale, and then the simplified models are simulated with MATLAB. The influence degree of various factors and the relationship of them during the operation are obtained. At last, experimental system is established to verify the correctness of the proposed models.

The Relationship of NaOH Molarity, Na2SiO3/NaOH Ratio, Fly Ash/Alkaline Activator Ratio, and Curing Temperature to the Strength of Fly Ash-Based Geopolymer

2011 ◽  
Vol 328-330 ◽  
pp. 1475-1482 ◽  
Author(s):  
M. M. A. Abdullah ◽  
H. Kamarudin ◽  
M. Bnhussain ◽  
I. Khairul Nizar ◽  
A.R. Rafiza ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Construction Industry ◽  
Curing Temperature ◽  
Test Results ◽  
Compression Tests ◽  
Naoh Solution ◽  
Alkaline Activator ◽  
Relationship Of ◽  
The Relationship

Geopolymer, produced by the reaction of fly ash with an alkaline activator (mixture of Na2SiO3 and NaOH solutions), is an alternative to the use of ordinary Portland cement (OPC) in the construction industry. However, there are salient parameters that affecting the compressive strength of geopolymer. In this research, the effects of various NaOH molarities, Na2SiO3/NaOH ratios, fly ash/alkaline activator, and curing temperature to the strength of geopolymer paste fly ash were studied. Tests were carried out on 50 x 50 x 50 mm cube geopolymer specimens. Compression tests were conducted on the seventh day of testing for all samples. The test results revealed that a 12 M NaOH solution produced the highest compressive strength for the geopolymer. The combination mass ratios of fly ash/alkaline activator and Na2SiO3/NaOH of 2.0 and 2.5, respectively, produced the highest compressive strength after seven days. Geopolymer samples cured at 60 °C produced compressive strength as high as 70 MPa.

The Influence of pH Value and SO42- Concentration on Strength of Cemented Soil

2011 ◽  
Vol 233-235 ◽  
pp. 2006-2010 ◽  
Author(s):  
Xiao Qiang Dong ◽  
Xiao Hong Bai ◽  
Yong Kang Lv ◽  
Peng Ju Han
Keyword(s):  
Compressive Strength ◽  
Ph Value ◽  
Solution Concentration ◽  
Corrosive Environment ◽  
Unconfined Compression ◽  
Cemented Soil ◽  
Set Up ◽  
Relationship Of ◽  
The Relationship ◽  
Influence Of Ph

The pH value and SO42- concentration in corrosive environment may affect mechanical property of cemented soil inturn to cause some serious damage to structure. The results of tests show that the unconfined compression strength is decreasing with the increase of H2SO4 solution concentration, increasing with the increase of pH value. The pH value is increasing and the SO42- concentration is decreasing with the increase of corrosive time. So it is concluded that compressive strength is closely rated with the pH value, SO42- concentration of corrosive environment and corrosive time. Finally a equation is set up based on the relationship of compressive strength and factors affected, which contain the reduced coefficient of compressive strength, pH value, SO42- concentration and corrosive time. The calculated and measured values are close so that the equation could be used in practical design for reference.

Study on the Relationship between Soil-Cement Parameters and Unconfined Compressive Strength

2011 ◽  
Vol 255-260 ◽  
pp. 4012-4016
Author(s):  
Jun Qing Ma ◽  
You Xi Wang
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Shear Strength ◽  
Unconfined Compressive Strength ◽  
Deformation Modulus ◽  
Soil Cement ◽  
Strength And Deformation ◽  
Cement Soil ◽  
Relationship Of ◽  
The Relationship

This paper studies relationship between soil-cement parameters and unconfined compressive strength. The research in tensile strength and deformation modulus of soil-cement is an important basis for soil-cement failure mechanism and intensity theory. They also impact cracks, deformation and durability of cement-soil structure. Shear strength and deformation of soil-cement is important to the destruction analysis and finite element calculations. Therefore it needs to study on tensile strength, shear strength and deformation modulus of soil-cement. Based on previous experiments, the relationship of tensile strength, shear strength, deformation modulus and unconfined compressive strength of soil-cement are quantitatively studied.

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