scholarly journals Studies on the Mechanical Properties of Dry, Saturated, and Frozen Marls Using Destructive and Non-destructive Laboratory Approaches

Author(s):  
Seyed Morteza Davarpanah ◽  
Mohammad Sharghi ◽  
Abolfazl Tarifard ◽  
Ákos Török ◽  
Balázs Vásárhelyi

AbstractThe mechanical properties of frozen rocks vary significantly from the properties of the same lithology under ambient temperature. The goal of this paper is to investigate these changes in the physical and mechanical properties of rocks due to saturation and freezing. Besides, the attention was paid on discovering new correlations between the mechanical characteristics. To fulfill these objectives, 36 uniaxial compressive strength tests, 36 Brazilian splitting tests, and 48 point load tests were carried out. The samples were tested in air dry, water saturated, and frozen (− 20 °C) conditions. The measured physical and mechanical parameters were analyzed by using regression analyses. It was found that the average uniaxial compressive strength of frozen samples (21.93 MPa) is 86.4% more than saturated ones (11.76 MPa) but 25.9% less than dry specimens (29.62 MPa). Additionally, high correlations were established between uniaxial compressive strength and IS(50) under air-dry, saturated, and frozen conditions for the investigated marl samples. Furthermore, it is of particular interest to observe a high correlation with the determination coefficient (R2 = 0.95) between the constants of previously published linear regressions of UCS- Is(50) under dry status.

Author(s):  
Haopeng Jiang ◽  
Annan Jiang ◽  
Fengrui Zhang

Experimental tests were conducted to study the influence of natural cooling and water cooling on the physical and mechanical properties of quartz sandstone. This study aims to understand the effect of different cooling methods on the physical and mechanical properties of quartz sandstone (such as mass, volume, density, P-wave velocity, elastic modulus, uniaxial compressive strength, etc.). The results show that the uniaxial compressive strength (UCS) and elastic modulus(E) of the specimens cooled by natural-cooling and water-cooling decrease with heating temperature. At 800℃, after natural cooling and water cooling, the average value of UCS decreased by 34.65% and 57.90%, and the average value of E decreased by 87.66% and 89.05%, respectively. Meanwhile, scanning electron microscope (SEM) images were used to capture the development of microcracks and pores within the specimens after natural-cooling and water-cooling, and it was found that at the same temperature, water cooling treatment was more likely to cause microcracks and pores, which can cause more serious damage to the quartz sandstone. These results confirm that different cooling methods have different effects on the physical and mechanical properties of quartz sandstone, and provide a basis for the stability prediction of rock mass engineering such as tunnel suffering from fire.


2020 ◽  
Vol 17 (2) ◽  
pp. 1059-1069
Author(s):  
Mohd Firdaus Md Dan ◽  
Edy Tonnizam Mohamad ◽  
Ibrahim Komoo ◽  
Aziman Madun ◽  
Siti Norsalkini Mohd Akip Tan

Engineering properties of tropical weathered granite mass have been widely investigated and classified for engineering purposes. However, the engineering properties of tropical boulder in weathered granite profile is poorly understood and not well classified. This study aims to examine and classify the physico-mechanical properties of granite boulder in completely weathered zone. A total of 34 in-situ boulders were examined from two granite quarries located in Southern Johor, Malaysia. Microstructure-mineralogical alterations were analyzed based on petrographic analysis and scanning electron microscopy (SEM). The mechanical properties were including dry density, porosity, point load strength, uniaxial compressive strength and permeability. Three properties were identified as significant indicators to differentiate between tropical boulder and completely weathered granite when it is evaluated from the soil investigation drilling work namely; texture characteristics, discolourations and degree of weathering. Analysis revealed that the alteration of microstructures and minerals such as feldspar, biotite, and plagioclase from corestone (Grade I/II) to saprolite (Grade IV/V) zone were significantly reduced the dry density, point load strength, uniaxial compressive strength and permeability with 32%, 99.5%, 98.6% and 84.8%, respectively. It has also significantly increased the porosity up to 11.6 times or 1065% from corestone to saprolite. The significant different of physico-mechanical properties of material surrounding boulder due to weathering can be classified and useful in evaluation of geotechnical design and geological engineering applications.


2013 ◽  
Vol 10 (4) ◽  
pp. 359-366 ◽  
Author(s):  
B. Adebayo ◽  
B. Adetula

This work deals with the investigation of physical and mechanical properties of selected rocks for condition of drilling categorization. Rock samples collected from five drilling locations were tested in the laboratory for uniaxial compressive strength, tensile strength, and Drilling Rate Index (DRI) using 1,100 kN compression machine, point load tester and miniature drill. Similarly, hardness, brittleness, Rock Abrasivity Index (RAI), penetration rate and bit wear rate were determined. The results showed that uniaxial compressive strength, tensile strength and Drilling Rate Index varied from 47.78 - 111.11 MPa, 8.09 - 19.44 MPa, and 20 - 52 respectively. The Nast point system chart was used to classify the rocks into drilling conditions. The drilling classification shows that the drilling condition of the rocks varied from slow to fast. The drillability characteristics of the rocks vary from extremely low to medium as specified by the Drilling rate Index (DRI). It was concluded that uniaxial compressive strength, texture and grain size, drilling rate index and Equivalent Quartz Content (EQC) are important parameters affecting drilling condition of the rocks.


2000 ◽  
Vol 22 ◽  
Author(s):  
G. R. Lashkaripour

The paper describes the statistical relationship between physical and mechanical properties of mudrock. It focuses particularly on the correlation between index parameters that are relatively easy to measure and mechanical properties that are difficult to determine. Data for regression analysis were extracted from available published information. Moreover, many tests were carried out on different types of mudrock from various sites. Reasonably good correlation is found between some index parameters and mechanical properties, and various regression equations are proposed for predicting mechanical properties for available data. There is a good correlation between the point load, water content, porosity, and modulus of elasticity with the uniaxial compressive strength, whereas the correlation between the density, elastic wave velocity, and Poisson's ratio with the compressive strength is poor. Theses correlations may aid engineers to make preliminary estimation of the mechanical properties of mudrock when samples of adequate size for testing are generally not available. Furthermore, the selective use of proposed relationships may even reduce the testing requirements of specific projects.


Author(s):  
María Elvira Garrido ◽  
Ferry B. Petnga ◽  
Víctor Martínez-Ibáñez ◽  
José B. Serón ◽  
Carlos Hidalgo-Signes ◽  
...  

AbstractThe effect of exposure to high temperature on rock strength is a topic of interest in many engineering fields. In general, rock strength is known to decrease as temperature increases. The most common test used to evaluate the rock strength is the uniaxial compressive strength test (UCS). It can only be carried out in laboratory and presents some limitations in terms of the number, type and preparation of the samples. Such constrains are more evident in case of rocks from historical monuments affected by a fire, where the availability of samples is limited. There are alternatives for an indirect determination of UCS, such as the point load test (PLT), or non-destructive tests such as the Schmidt’s hammer, that can also be performed in situ. The aims of this research are: (i) measuring the effect of high temperatures and cooling methods on the strength and hardness of a limestone named Pedra de Borriol widely used in several historic buildings on the E of Spain, and (ii) studying the possibility of indirectly obtaining UCS by means of PLT and Leeb hardness tests (LHT), using Equotip type D. Limestone samples were heated to 105 (standard conditions), 200, 300, 400, 500, 600, 700, 800 and 900 ºC and cooled slowly (in air) and quickly (immersed in water). After that, UCS, PLT and LHT tests were performed to evaluate the changes as temperature increases. Results show decreases over 90% in UCS, of between 50 and 70% in PLT index and smaller than 60% in LHT index. Insignificant differences between cooling methods were observed, although slowly cooled samples provide slightly higher values than quickly cooled ones. The results indicate that LHT can be used to indirectly estimate UCS, providing an acceptable prediction. Research on correlating strength parameters in rocks after thermally treated is still scarce. This research novelty provides correlations to predict UCS in historic buildings if affected by a fire, from PLT and non-destructive methods such as LHT whose determination is quicker and easier.


2018 ◽  
Vol 2 (4) ◽  
Author(s):  
Mehdi Jalili ◽  
Mohmad Reza Ghasemi ◽  
Ali Reza Pifloush

In some parts of the world mechanical properties of problematic soils are not suitable for construction purposes. Today, regard to the importance of the soil improvement; by considering methods with more concordance with the environmental mechanisms in the nature, and with study and combination of geotechnical science, microbiology and geochemistry; researchers try to provide a suitable way to improve the physical and mechanical properties of the problematic soils. In this paper, the effect of the aerobic microorganisms of Sporosarsina Pasteurii (PTCC 1645), as a producer of Urease for the sedimentation of calcium carbonate and improvement of granular soil of Garmsar Industrial Town is evaluated experimentally in order to check the effects of this phenomena on the shear strength and stiffness of the granular soils. The results of the uniaxial compressive strength tests show the effect of adding the above mentioned microbial solution to the soils, in case of increased uniaxial compressive strength and stiffness of the soil. It should be mentioned that the granular soils have no compressive strength, naturally but after bio cementation the samples got notable values.


2019 ◽  
Vol 1 (2) ◽  
pp. 114-117
Author(s):  
Mohd Firdaus Md Dan

The aim of this research is to investigate the effect of spheroidal weathering on the physico-mechanical properties of in situ granite boulder in tropical environment. This research was conducted to gain more understanding due to lack of study related to this topic especially on tropical boulder in completely weathered zone. A number of 34 in situ granite boulders that naturally formed in completely weathered zone were selected and investigated from two quarries located in Southern Johor, Malaysia. Classification of weathering grade was conducted on the material surrounding boulder based on discolouration, degree of friability and texture characteristics as suggested by ISRM(1). The colour of the weathered material were classified based on Rock Colour Chart (2). Petrographic analysis and scanning electron microscopy (SEM) were carried out to analyze the mineralogical and microstructure alterations, respectively due to weathering effect. The changes of physico-mechanical properties at the surrounding of boulder due to weathering were also analyzed including dry density, porosity, point load strength, uniaxial compressive strength and permeability. The dry density and porosity were conducted based on ASTM (3) and Brown (4), respectively. The point load uniaxial compressive strength were carried out according to ISRM (1) while permeability test was undertaken based on Head (5). The tropical granite boulder possessing rindlets with significant different of colours, degree of friability and texture. This differences were classified into four primary zones: corestone (C), inner rindlets (IR), outer rindlets (OR), and saprolites (S) with weathering grade of II, III/IV, IV/V and V, respectively. Due to spheroidal weathering, three to six concentric sheets of rindlets with whitish grey to light brown colour were formed at the surrounding of corestone's boulder. Each sheets of rindlets has 2.0 cm to 3.0 cm thick with total thickness up to 80 cm. The microcracks aperture of IR and OR is ranging from 150 to 200 µm and 200 µm to 1 mm, respectively. Analysis revealed that the higher the weathering grade, the higher and wider the fracture opening formed in the rindlets up to 2 mm width. Analysis exibited that the increase of weathering grade from Grade II to IV along C to S were significantly reduced the plagioclase, K-feldspar, and biotite with reduction of 74%, 74.2% and 87.5%, respectively. The alteration of minerals and microstructure due to the weathering were significantly reduced the dry density, point load strength, uniaxial compressive strength and permeability with 32%, 99.5%, 98.6% and 84.8%, respectively.The reaction of spheroidal weathering is significantly affecting the physico-mechanical properties of the tropical granite boulders by alteration of its minerals and microstructure characteristics at the surrounding of the boulder.


2021 ◽  
Vol 73 (09) ◽  
pp. 871-880

The paper presents the results of laboratory testing of clay samples from two localities in the city of Zagreb, mixed with fly ash, slag and cement. Under laboratory conditions, composite samples of clay mixtures with binders were prepared, where the binders are added to the clay in ratios of 5 %, 10 % and 20 %, and tested at different maturation time intervals of 7, 14 and 28 days. The influence of different type and amount of binder and age of the composite sample on moisture and uniaxial compressive strength was examined and analysed. The obtained results show that the utilization of cement, fly ash and slag can improve the physical and mechanical properties of Zagreb clay, depending on the amount of binder and the maturation time of the composite.


2012 ◽  
Vol 4 (1) ◽  
pp. 1
Author(s):  
Djoko Purwanto

Timber Acacia mangium (Acacia mangium, Willd) for Furniture. The study aims to determine the mechanical and physical properties and the decorative value (color and fiber) wood of acacia mangium with using finishing materials. This type of finishing material used is ultran lasur natural dof ,ultran lasur classic teak, aqua politur clear dof, aqua politur akasia dan aqua politur cherry. After finishing the wood is stored for 3 months. Test parameters were observed, namely, physical and mechanical properties of wood, adhesion of finishing materials, color and appearance of the fiber, and timber dimensions expansion. The results showed that the mechanical physical properties of acacia wood qualified SNI. 01-0608-89 about the physical and mechanical properties of wood for furniture, air dry the moisture content from 13.78 to 14.89%, flexural strength from 509.25 to 680.50 kg/cm2, and compressive strength parallel to fiber 342.1 - 412.9 kg/cm2. Finishing the treatment process using five types of finishing materials can increase the decorative value (color and fiber) wood. Before finishing the process of acacia mangium wood has the appearance of colors and fibers and less attractive (scale scores 2-3), after finishing acacia wood fibers have the appearance of colors and interesting and very interesting (scale 4-5).Keywords: mangium wood, mechanical properties, decorative value, finishing, furniture.


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