Prediction of Basic Mechanical Properties of Tuffs Using Physical and Index Tests

The main objective of this experimental work is to determine the physico-mechanical properties of tuffs used as building stone and to investigate the relationships between basic mechanical properties (compressive strength, flexural tensile strength, loss of volume by abrasion and impact strength) as well as physical and index properties (apparent porosity, dry unit weight, water absorption, P-wave velocity, Brinell hardness and point load index) of tuffs which are relatively easy to implement and low cost. The rock type investigated in this study was tuffs. Statistical analyses were performed to correlate the different properties. The results show that there are good and satisfactory relationships between the mechanical and physical-index properties of tuffs. © 2018, Pleiades Publishing, Ltd

Estimation of Los Angeles abrasion resistance of igneous rocks from mechanical aggregate properties

Aggregates are one of the most common materials used in engineering projects, and they are exposed to a variety of physical and chemical influences depending on the areas in which they are used. An aggregate should generally be hard, durable, uniform and clean, as well as highly abrasion-resistant. It must not contain harmful substances that can cause alkali-silica reactions. One of the most important properties for determining the quality of an aggregates is its abrasion resistance; the best known and most widely applied test used to measure abrasion resistance is the Los Angeles abrasion test (LA). Although the relationship between rock properties and LA has been investigated by some researchers, the relations between other aggregate strength properties and LA has not been clearly defined. In this study, thirty-nine igneous rock aggregates were tested to measure the quality of the aggregates and to determine the relationships between the LA values and the mechanical-physical properties of the aggregates. The LA values of the tested aggregates ranged from 16.13 to 58.9%. Both simple and multiple regression analysis techniques were used to evaluate in detail the test results obtained from the experiments. The LA value was estimated with the help of some aggregate tests (rock impact hardness-RIHN, coefficient of rock strength-CRS and aggregate crushing value-ACV, etc.) which can be done by using small amounts of the aggregates and relatively simple test tools. The aim of this study is to estimate in a practical way, the abrasion resistance of the aggregates with the help of these correlations, which were obtained by using relatively simple tests. The regression analyses (simple and multiple) indicated strong correlations between LA and mechanical tests of aggregate. © 2017, Springer-Verlag GmbH Germany

Determination of mechanical properties of rocks using simple methods

Statistical equations have been determined for estimating the mechanical properties of rocks using non-destructive and indirect test methods. Nineteen different rock types were tested to obtain the relationships between Shore hardness, point load index, sound velocity, Schmidt hardness and porosity and uniaxial compressive strength, indirect tensile strength and abrasion resistance. Results of regression analyses showed satisfactory correlations. © Springer-Verlag 2008.Acknowledgments The authors would like to thank to the Cukur-ova University Scientific Research Fund for supporting this research (Project Number: FBE. 2004. YL.1)

Effect of grout strength on the stress distribution (tensile) of fully-grouted rockbolts

The paper deals with and axial stress distribution (ASD) obtained from pull-out tests of strain gauged rockbolts in high strength rock media. For this purpose, an experimental research was conducted considering the only axial forces acting on fully grouted rockbolts (FGR). Strain gauges were used to observe the behavior of rockbolts and to determine the load transfer mechanism of the bolts to rock mass. In the test, five grout mixture having different properties was prepared and stress–strain mechanism of the bolt-grout interface was investigated for these conditions. ASD was demonstrated elastic load transfer behavior from the rockbolt to the outlying rock under the applied load (for each grout type) and stress concentration was rather a high level at 70 mm distance from rock surface. Axial stress curves drawing with the aid of strain readings were showed the regular distribution with increasing of grout stiffness. The test results of strain gauged rockbolts show that the shear stress distribution (SSD) is uniform and, the style of the distributions along the rockbolt was similar under various loading levels for all grout types. Shear stress was rather a small amount at the pulling end of rockbolt but it reached the peak after a short distance away from the pulling end of rockbolt and subsequent to peak value decayed rapidly with the load increase. The results were showed that strength properties of grout played an important role in SSD and ASD along the rockbolt. The increase in grout strength and rigidity made the stress distributions regular along the rockbolt. © 2018 Elsevier LtdThe authors would like to thank the Scientific Research Fund of Çukurova University for supporting this research. Project No: MMF 2009 D7 . Appendix

Determination of mechanical properties of rocks using simple methods

Statistical equations have been determined for estimating the mechanical properties of rocks using non-destructive and indirect test methods. Nineteen different rock types were tested to obtain the relationships between Shore hardness, point load index, sound velocity, Schmidt hardness and porosity and uniaxial compressive strength, indirect tensile strength and abrasion resistance. Results of regression analyses showed satisfactory correlations

Estimation of Compressive Strength of Concrete Using Physico-Mechanical Properties of Aggregate Rock

This study examines the influence of the physico-mechanical properties of the intact rock of aggregate materials on the strength performance of a concrete. For this aim, nine different aggregate types were produced from nine different intact rocks, and they were used in the production of nine different concretes. The physical and mechanical properties of the corresponding rocks were varied between 7.8 and 123.3 MPa, 13.30 and 26.40 kN/m3, 2.29 and 34.43%, and 1.30 and 4.34 km/s, for compressive strength (CSr), unit weight (UWr), porosity (nr), and ultrasonic pulse velocity (UPVr), respectively. During the making of the concretes, water–binder ratios were kept between 0.28 and 0.55 based on the slump and workability. According to 28-day compressive strengths, strong correlations were obtained from the physico-mechanical properties of the corresponding aggregate rocks and the compressive strength of the concretes (CSc). While the increasing the Young’s modulus (Er), CSr, UWr and UPVr of corresponding aggregate rocks increased the strength of concretes, the increase in the nr of corresponding aggregate rocks decreased the strength of concrete. The results obtained from this study indicated that knowing any physical or mechanical property of rock used for producing aggregate could be used to estimate the compressive strength of concrete. © 2018, Shiraz University.Istanbul ÜniversitesiAcknowledgements The authors would like to thank to Scientific Research Projects Coordination Unit of Istanbul University for supporting this research (Project Number: 30744)

The effects of scoria and pumice aggregates on the strengths and unit weights of lightweight concrete

This study examines the influence of aggregate types on the unit weight and strength characteristics of lightweight concretes (LWC). In this study, a scoria aggregate light weight concrete (SLWC), a pumice aggregate light weight concrete (PLWC) and three scoria-pumice commixture aggregate light weight concretes (SPLWC-I, SPLWC-II and SPLWC-III) were produced. Average dry unit weights of SLWC, SPLWC-I, SPLWC-II, SPLWC-III and PLWC mixtures were 1997, 1696, 1638, 1477, 1368, kg/m3, respectively. Compressive and flexural tensile strength and unit weight of concrete were determined at 28 days. SLWC, SPLWC-I, SPLWC-II, SPLWC-III and PLWC mixtures developed 44.1, 30.5, 27.6, 23.3, 15.8 MPa compressive strength, respectively, which satisfy the load bearing requirements. In terms of strength and unit weight requirements, all concrete produced can be classified as well as used as a LWC. © 2009 Academic Journals

The influence of aggregate type on the strength and abrasion resistance of high strength concrete

This paper examines the influence of aggregate type on the strength characteristics and abrasion resistance of high strength silica fume concrete. Five different aggregate types (gabbro, basalt, quartsite, limestone and sandstone) were used to produce high strength concrete containing silica fume. Silica fume replacement ratio with cement was 15% on a mass basis. Water-binder ratio was 0.35. The amount of hyperplasticizer was 4% of the binder content by mass. Gabbro concrete showed the highest compressive and flexural tensile strength and abrasion resistance, while sandstone showed the lowest compressive and flexural tensile strength and abrasion resistance. High abrasion resistant aggregate produced a concrete with high abrasion resistance. Three-month compressive strengths of concretes made with basalt, limestone and sandstone were found to be equivalent to the uniaxial compressive strengths of their aggregate rocks. However, the concretes made with quartsite and gabbro aggregate showed lower compressive strength than the uniaxial compressive strength of their aggregate rocks. © 2007 Elsevier Ltd. All rights reserved

The effects of scoria and pumice aggregates on the strengths and unit weights of lightweight concrete

This study examines the influence of aggregate types on the unit weight and strength characteristics of lightweight concretes (LWC). In this study, a scoria aggregate light weight concrete (SLWC), a pumice aggregate light weight concrete (PLWC) and three scoria-pumice commixture aggregate light weight concretes (SPLWC-I, SPLWC-II and SPLWC-III) were produced. Average dry unit weights of SLWC, SPLWC-I, SPLWC-II, SPLWC-III and PLWC mixtures were 1997, 1696, 1638, 1477, 1368, kg/m(3), respectively. Compressive and flexural tensile strength and unit weight of concrete were determined at 28 days. SLWC, SPLWC-I, SPLWC-II, SPLWC-III and PLWC mixtures developed 44.1, 30.5, 27.6, 23.3, 15.8 MPa compressive strength, respectively, which satisfy the load bearing requirements. In terms of strength and unit weight requirements, all concrete produced can be classified as well as used as a LWC