Slake Durability Index Test Research Articles

A NOVEL WAY TO CLASSIFY THE SLAKE DURABILITY INDEX OF ROCKS

Slaking, the disintegration of rocks upon exposure to moisture and air, poses significant challenges in engineering applications, such as in slope stability and embankment design. This study improves the slake durability index test by introducing several enhancements to better reflect the field conditions of rocks. A new test methodology is developed which includes a revised slake durability classification table, a novel Discard Method for calculating weight retention in the test drum, and an updated classification chart. The improved methodology considers parameters such as porosity and strength, evaluated through index, Schmidt hammer rebound and point load tests. The new classification table categorizes rocks into durability classes according to the field observations and laboratory test results. The Discard Method improves accuracy by eliminating broken pieces from the durability calculation, addressing the limitations in the suggested method. A Configured Discard Method equation further defines the durability estimation by combining porosity, strength and slake durability data. Field investigations and laboratory tests conducted with various rock types demonstrate that the new classification system provides more accurate and practical assessments of rock durability. This study highlights the importance of effective porosity and strength impact which enhance the reliability of slake durability evaluations, offering a revised classification framework that simplifies field assessments while maintaining the accuracy. Future research should focus on developing these methods and expanding their applicability to diverse geological contexts by including more material to test.

Point Load Strength Index and Slake Durability Index of Marbles from the Kanti Highway, Central Nepal LesserHimalaya

Point Load Strength Index (PLSI) is determined to obtain the strength of the rock, while Slake Durability Index (SDI) offers quantitative data on the mechanical behavior of rocks exposed to cyclic wetting and drying. This study aims to find out such index properties of marbles from the Markhu Formation of Central Nepal, Lesser Himalaya. The study of the strength and durability of marbles is crucial to classifying strength and identifying resistance to weathering, deterioration patterns, and rock quality. Fresh rock samples were collected from 20 different locations within the Markhu Formation, exposed across the Kanti Highway. The SDI and PLSI tests were carried out. The study reveals that the PLSI ranges from 2.54 to 9.08 MPa, and the test samples belong to strong to very strong rock categories according to the calculated value of UCS, indicating that the marbles from the Markhu Formation are of good quality and are strong enough to withstand the load, contributing to rock mass quality. The marbles have extremely high second cycle SDI (Id2) of 98.92% to 99.50%, and therefore, a high resistance to the wetting and drying cycle, showing slow slaking behavior. Between the second and the fifth cycle, SDI (Id5) was deduced by about 1%. It implies that the marbles are highly resistant to weathering and erosion. Marble shows two kinds of disintegration after the second cycle and deteriorates under three types of patterns under five cycles.

Effects of groundwater and distilled water on the durability of evaporitic rocks

Evaporitic rock durability induced by groundwater cause several construction challenges, but representative experimental studies to evaluate such conditions are still missing. Therefore, this study intended to provide better and more realistic degradability features of evaporites with groundwater besides a comparison with distilled water as slaking fluids. Forty-eight evaporitic rock blocks were collected from Abu Dhabi area, United Arab Emirates. 96 slake durability index (SDI) tests were performed, 48 with each of the slaking fluids; groundwater and distilled water, and their textural, mineralogical, and geochemical attributes were also examined before and after the SDI tests. In comparison to mineralogical and textural modifications, slaking fluid had a greater impact on the chemical composition of evaporitic rock. The study shows that the degradability of evaporites with groundwater and distilled water indicates a wide range from very low to high. The mean weight loss values after four cycles with groundwater and distilled water vary from 11 to 77 and from 4 to 81 wt.%, respectively. Consequently, slaking with groundwater illustrates a wide range compared to the slaking with distilled water. This could be due to quick interactions between groundwater and evaporites and fast hydration-dehydration process than distilled water due to the chemical composition of the groundwater. It is recommended to investigate the attributes of evaporitic rocks as well as groundwater geochemistry for safe, cost-effective, and sustainable structures.

Shear Strength and Durability Behaviors of Compacted Weathered Clay Shale Mixture Using Portland Cement

The use of weathered clay shale often has the potential to cause geotechnical problems as an embankment material, especially slope failures. In order for weathered clay shale to be used as embankment material, the weathered clay shale must be mixed with other materials. An example of a widely used mix is a mix with a Portland cement (PC). In general, this mixture will increase the shear strength of the embankment material. In addition to shear strength, it is very important to investigate whether the material mixture is susceptible to durability. Therefore, this study aims to evaluate the shear strength and durability behaviors of weathered clay shale mixture, using PC. The percentage of this cement was varied and did not exceed 20%, with the mixing material also compacted based on Proctor Standard procedure. This test included the determination of shear strength and durability index at the smaller and larger (dry and wet sides) than optimum moisture content (OMC). Shear strength and durability index were determined by Triaxial and slake durability index tests, respectively. The results showed that the weathered clay mixture with 10% PC and 8% larger OMC led to an increase in the normalized shear strength (∆σ/σ) and durability index at approximately 300% and 24%, respectively, compared to the original clay shale. This indicated that the optimum shear strength and durability of this shale mixture were highly observed at 10% PC and 8% larger OMC (wet side). This verified also although the durability index increased by 97% with the addition of 20% PC, whose utilization was found to be unrealistic

EXPERIMENTAL INVESTIGATION OF DURABILITY AND STRENGTH OF SANDSTONE AND SHALE OF UNITED MINERAL COAL COMPANY SOR-RANGE, BALOCHISTAN


 
 
 
 Mining operations deal mainly with hard and soft rocks with different mechanical properties and varying strengths. The aim of the slake durability test is to present an index related to degradation resistance of rock when exposed to standard cycles of wetting and drying. Research in geology and rock mechanics is done to explain the influence of the rock index properties in determining the strength, durability and pulse velocity of the rock. This paper enlightens the prediction of the rock’s behavior and nature of the degradation of rocks The index values obtained for sandstone are varying from 97.36 to 99.04% and for shale it ranges from 10.21 to 14.06%. The slake durability index test for sandstone sample indicates that it is high durable and the shale indicates very low durability. The average value of uniaxial compressive strength was calculated to be 83.144 MPa.
 
 
 

Comparative Study on Degradability Characteristics of Evaporitic and Carbonate Rocks from Al Ain, United Arab Emirates

The slake durability index (SDI) test is a well know and extensively used to measure the degradability behaviour of rocks especially for weak rocks like mudstone, shale, evaporites, carbonates, etc. The degradability of rocks plays a critical role in engineering design process either on or in the rock mass for safe and sustainable structures. Evaporitic and carbonate rocks are vulnerable to physical, chemical and mechanical weathering, break down, as result of wetting-drying processes during the SDI test. Evaporites and carbonates are outcropped at the surface and subsurface of the Al Ain city, which is located on the south-eastern of Abu Dhabi, capital city of the United Arab Emirates (UAE) at various level, and it is one of the rapid growing cities in the UAE. However, the detailed comparative data on the slaking behaviour of evaporites and carbonates are not available presently in the study area. Therefore, this paper provides a comparative study on the degradability characteristics of evaporitic and carbonate rocks in the city of Al Ain as well as comprehensive data for the study area. 142 rock blocks (∼ 40×40×40 cm3 in size), which represent evaporitic (48 blocks) and carbonate (94 blocks) rocks were collected from various accessible either surfaces outcrops or excavated areas from the study area. 48 and 94 slake durability test samples of evaporites and carbonates were prepared and slake durability tests were performed according to the American Society for Testing and Materials (ASTM) standards. Furthermore, their compositional and textural characteristics were examined using polarized-light microscope, X-ray diffractometry (XRD), X-ray fluorescence (XRF) and scanning electron microscope (SEM). The degradability data for evaporite and carbonate rocks designate medium to very low and extremely high to very high values based on the classification after multiple cycling, Id1 to Id4, processes, respectively. The weight loss values from the first to the fourth cycles (Id1–Id4) of evaporite and carbonate samples are approximately 24–95 and 0.68-4.22 wt%. Obviously, evaporites are highly vulnerable compare to carbonates because of their differences in chemical and mineralogical structures and their reactions to the slaking fluid of distilled water. Hydration-dehydration effects on the evaporitic rocks may occur within short time compare to the carbonate rocks due to their natural occurrences. Thus, this study provide comparable and details information for the degradability characteristics of evaporitic and carbonate rocks, and likely improve the understanding of the durability of both rock types in the study area and elsewhere. Especially, such a reliable and inclusive information will compromise a practical guideline for engineers and decision makers to overcome difficulties on durability problems associated with evaporites and carbonates in the study area and elsewhere.

Railroad ballast of granites and basic rock in tropical regions: relationships between petrography, physical-mechanical properties and alterability

The objective of this study was to evaluate, comparatively, the evolution of this degradation of three rock types, two granitoids and a microgabbro which, eventually, could be used as ballast, due to the proximity of the quarries to the design route of a railroad to be built between São Paulo and around Campinas, State of São Paulo, southeastern Brazil. They were tested for alterability in sodium sulfate and ethylene glycol solutions. Based on detailed petrographic analysis, Micro-Deval and Slake Durability Index tests were performed with and without conjugation to the referred alterability tests. The results obtained are punctual, valid and positive for the samples of the rock masses carefully selected and described, considering the different characteristics of the granitoids belonging to the Morungaba and Cantareira Complexes. In the case of basic rock, the microgabbro, should not be used as ballast in the studied tropical climate area, since the exposed fragments that make up the ballast are intensely affected by chemical weathering (notably reactions accelerated by water and temperature), which culminate in the decomposition of primary minerals and, consequently, in the faster physical-mechanical degradation of this rock. In practice, more frequent periodic maintenance and higher costs.

Slaking behavior of evaporitic rocks from Abu Dhabi area, United Arab Emirates

Slaking behavior of rocks is an essential indicator of their ability to resist degradation and is commonly assessed via the second cycle of slake durability index (Id2, SDI) test. In Abu Dhabi area, the evaporitic rocks commonly extend from the near surface to several meters depth, so that they lie at the foundation level of buildings and other infrastructures. Evaporites pose significant challenges for the construction sectors due to the easily degradable nature of these rocks. This study presents new and definitive data for evaporites that provides essential information for the construction businesses, engineers, and decision makers. Eighty-six rock blocks from eleven locations were collected. A representative sample of each block was extracted for slake durability testing. Samples were prepared and tested according to ASTM standards. Before and after the slaking process, the mineralogical composition and characteristic textures of the samples were examined in petrographic thin section and via XRD (X-ray diffraction), XRF (X-ray fluorescence), and SEM (scanning electron microscopy) analyses. Based on multiple cycling, Id1 to Id4, the slake test data for evaporitic rocks from Abu Dhabi indicate high to very low values. The weight loss values from the first to the fourth cycle (Id1–Id4) of all samples lie in the range 40 to 93 wt%. This is attributed to chemical and mineralogical properties of the evaporites, which allow rapid development of hydration-dehydration effects. The evaluation of the slaking behavior of evaporitic rocks provides explanations for durability problems associated with these rocks in the study area and elsewhere.

Correlation of Uniaxial Compressive Strength with Indirect Tensile Strength (Brazilian) and 2nd Cycle of Slake Durability Index for Evaporitic Rocks

In engineering applications of rock materials, predicting the uniaxial compressive strength (UCS) is essential, particularly in the preliminary stage of a project. The UCS of rock materials is profoundly affected by the rock type, porosity, grain size, water content, etc. The rigor and cost of sampling as well as sample preparation are more than those of the Brazilian (indirect tensile strength, ITS) and 2nd cycle of slake durability index (Id2) tests. Therefore, ITS or Id2 values can be used to predict the UCS value of rocks through correlation. In this study, evaporitic rocks from Al Ain, United Arab Emirates (UAE) were examined. Forty-eight representative rock blocks were collected, while avoiding anisotropy effects of thinly bedded rocks along with the gypsiferous layers. The relations between UCS and ITS and UCS and Id2 were estimated with representative empirical equations. Results reveal moderate correlation between them. Moreover, Student’s t and F tests show that there is a significant correlation between UCS and ITS and Id2. Further, the fit between the predicted and measured values was evaluated in terms of the 1:1 line, a good index to confirm the reliability of the empirical relationship. Finally, the study demonstrates that ITS or Id2 can estimate the UCS of evaporitic rocks within a certain correlation coefficient, R.

Durability classification of red beds rocks in central Yunnan based on particle size distribution and slaking procedure

Moisture induced disintegration of soft rock in Red Beds is common all over the world. The slake durability index test is most useful to quantify durability of the soft rocks. Based on a series of slaking test, this article aims to develop a durability classification involving particle size and slaking procedure. To describe the slaking procedure in detail, the Relative Slake Durability Index (Idi) is proposed. The Idi is the percentage ratio of the ith weight of oven-dry retained portion to the (i-1)th weight of ovendry retained portion. Results show that the Idi of samples have a large difference in certain slaking procedure, whereas the traditional Durability Slake Index (Id) is almost constant. Considering this limitation of Id in durability classification, an advanced classification by applying the Idi and disintegration ratio (DR) is further established in this article. Compared to the durability classification based on Slake Durability Index (Id), the new classification accounts for the particle size of the slaked material and the slaking procedure, so it provides a better measure of the degree of slaking. The classification recommended in this article divide the slake durability into three classes (i.e., low, medium and high class). Furthermore, it divides both the low class and the medium class into 3 subclasses.

Preparation and evaluation of spherical samples for Slake Durability Index test

Slake Durability Index test is being widely used to determine the disintegration characteristics of the weak rocks when they are subjected to drying and wetting cycles. In the test standards, samples are recommended to have rounded or close to spherical shape. In this study, a new method called as Pasha Method was proposed and applied to prepare equal-sized spherical samples. Slake Durability Index tests were performed on the spherical and rounded sample sets prepared from different rock types. According to Slake Durability Index test results in all rocks, the difference between the first cycle and second cycle results of the rounded samples and the spherical samples is found as 0.05–8.04% and 0.1–13.63%, respectively. When only the spherical test results were considered, the difference in the first cycle and second cycle values is found to be 0.28–2.19% and 0.44–7.57%, respectively. Applying this new method allows researchers to perform this test on equal-sized spherical samples, resulting in the minimization of the shape effect on the test results.

Issues in Engineering Geological Classification of Weathered Sedimentary Rocks: Case Study of Kati Formation, Parit, Perak

Kati Formation consists of alternating layers of sandstone, siltstone and mudstone that results in non-uniform weathering. The presence of surficial features due to weathering such as iron bands, iron recementation, iron staining and lithobionts coating in an uneven distribution on the outcrop causing more complexity to the heterogeneous sedimentary rocks which are also tectonically deformed. The presence of iron recementation in highly weathered rocks causing the rock strength to be higher than the moderately weathered rocks. Thus, several laboratory tests are conducted in this study to characterise the weathered rocks which are uniaxial compressive strength (UCS), point load strength index, slake durability test, jar slake test and Schmidt hammer rebound test. Among the laboratory tests conducted in this study, slake durability index test, Id2 is the ideal test to characterise the rock samples of different weathering grades as it gives a large range of laboratory test results which is 0.3 % to 15.0 % for completely weathered, 22.0 % to 67.0 % for highly weathered, 68.0 % to 83.0 % for moderately weathered and 87.0 to 98.0 % for slightly weathered to fresh rocks. The values obtained are not affected by the uneven distribution of iron oxide present in the rock samples.

Durability Assessment of Clay-Bearing Soft Rocks By Using New Decay Index

Clay-bearing rocks are known as most important problematic weak rocks. Due to the importance of disintegration of clay-bearing rocks in engineering projects, several simple test methods have been proposed to assess durability of these rocks. In this study, a comprehensive research program was conducted on twenty different clay-bearing rocks to assess their disintegration characteristics under laboratory conditions. In order to carry out the research, at the first step some physical and mechanical properties of the studied rocks were measured. After that, three durability test methods were employed. These tests include the standard slake durability test to obtain index durability (Id2 ), slake durability test with sieving the remained materials in drum to obtain disintegration ratio (DR) and new time series slake durability test to obtain decay index (DI). The results of this research indicated that for most of samples, using the standardized slake durability index test (Id2 ) may not be adequate to understand the disintegration characteristics of clay-bearing rocks and shows overestimated values. The new decay index (DI) has overcome the most limitations of the standard slake durability test and clearly will realize deterioration potential of clay bearing rocks. Finally, based on the results of decay index a new durability classification was proposed.

The Effect of pH of the Testing Liquid on the Degradability of Carbonate Rocks

The degradability of rocks is among the features of great importance in any projects relevant to geological, mining, civil or environmental. Slake durability is a measure of degradability of rocks due to the process of mechanical, physical and chemical breakdown. The aim of this study is to assess the influence of pH of testing liquid on degradability of carbonate rocks by performing slake durability index test in various acidic and alkaline watery environments. To obtained the aim, mineralogical composition along with slake durability tests under variable pH conditions both in acidic and alkaline environments (from pH 2 to 10), on different type of travertine and limestones, collected from stone quarries operated in the southwestern Turkey, were examined. Testing fluid was prepared by adding appropriate amount of HCI (for acidic solutions) and NaOH (for basic solutions) to distilled water. Further, those properties of rock including strength, dry and saturated densities, effective porosity and sonic wave velocity were studied to investigate the impact of those properties on the degradability of rocks. The results revealed that the relationship between slake durability of the carbonate and the pH of the testing liquid used for testing would not yield a correlation. It is concluded that density, porosity and texture of rocks have noteworthy impact on degradability of rock. Further, fine grained rocks are more susceptible to degrade comparing the coarse grained rocks.

A Durability Classification of Clay-Bearing Rocks Based on Particle Size Distribution of Slaked Material

Clay-bearing rocks disintegrate at varying rates, due to slaking, when exposed to moisture. This research aims to develop a durability classification of clay-bearing rocks based on particle size distribution of slaked material, quantified in terms of disintegration ratio (D R ). D R is the ratio of the area under the particle size distribution curve of slaked material for a sample, upon completion of the standardized slake durability index test, to the total area encompassing all particle size distribution curves of the samples tested. Although second-cycle slake durability index (Id 2 ) is the most frequently used parameter for classifying the slaking behavior of clay-bearing rocks, it does not consider the range of particle sizes in the slaked material after the test. Compared to Id 2 , D R accounts for all particle sizes present in the slaked material and provides a better measure of the degree of slaking. The slake durability index test was used to investigate the slaking behavior of samples from 20 different clay-bearing rocks, and Id 2 and D R values were determined for all samples. Id 2 showed a nonlinear relationship with D R . The relationship was used to develop a durability classification, based on disintegration ratio, as follows: low durability: D R = 0 to 0.20; medium durability: D R = 0.20 to 0.65; medium-high durability: D R = 0.65 to 0.85; and high durability: D R = 0.85 to 1.00. In order to use this classification, one needs to perform a sieve analysis on material left after the slake durability test and determine D R .

Slope failure in stratified rocks: a case from NE Himalaya, India

Mountainous regions of India experience recurrent slope failures due to rapid urbanization. The main causes of slope failure are high precipitation aided by unplanned construction of cut slopes. Such slope failures are further aggravated because of the presence of low strength, highly jointed, stratified rocks rich in clay minerals. In general, effect of weathering is more pronounced in these rocks, which causes long-term time-dependent deterioration of the rocks as well as joint strength. In this regard, the present investigation deals with the causes, behavior, and mechanism of slope failure by examining a section in the North Eastern Himalayas. A detailed field investigation was carried out for examining the existing condition of slope, slope material, and joint parameters. Laboratory experiments like compressive and tensile strength tests along and across the lamination planes along with slake durability index tests were conducted to characterize the material and investigate the role of weathering in strength degradation. Later, numerical simulation was performed employing distinct element method to investigate the failure behavior, mechanism, and also the effect of water pressure in destabilizing the slope. The experimental result indicates directional strength variations parallel and perpendicular to bedding plane, which makes the rock incompetent to sustain external load. The presence of orthogonal joint sets accelerates the process of block detachment. Significant slaking was observed which further deteriorates and fragments the rock at deeper level. Numerical simulation shows that failure plane is dominantly planar (along the bedding parallel joints) and surficial.

Determination of Slake Durability Index (Sdi) Values on Different Shape of Laminated Marl Samples

The slake durability index (SDI) test is widely used to determine the disintegration characteristic of the weak and clay-bearing rocks in geo-engineering problems. However, due to the different shapes of sample pieces, such as, irregular shapes displayed mechanical breakages in the slaking process, the SDI test has some limitations that affect the index values. In addition, shape and surface roughness of laminated marl samples have a severe influence on the SDI. In this study, a new sample preparation method called Pasha Method was used to prepare spherical specimens from the laminated marl collected from Seyitomer collar (SLI). Moreover the SDI tests were performed on equal size and weight specimens: three sets with different shapes were used. The three different sets were prepared as the test samples which had sphere shape, parallel to the layers in irregular shape, and vertical to the layers in irregular shape. Index values were determined for the three different sets subjected to the SDI test for 4 cycles. The index values at the end of fourth cycle were found to be 98.43, 98.39 and 97.20 %, respectively. As seen, the index values of the sphere sample set were found to be higher than irregular sample sets.

On the variations of geo-engineering properties of dunites and diorites related to weathering

Geo-engineering properties of rocks, including discontinuity properties, physical and mechanical properties and crack propagation under axial loads, are affected by weathering. All of these rock properties have an impact on various scales on engineering applications. Therefore, weathering-related variations on rocks and rock masses are of great importance. In this study, dunites and diorites are compared from the view of weathering-related geo-engineering property variations both on field and on laboratory scales. The studies were initiated in the field by measuring the discontinuity properties, including spacing, aperture fill material, roughness and Schmidt hammer rebound tests. Mineralogical and petrographic investigations were performed on thin sections gathered from different weathering grades. The quantitative petrographic studies were concentrated on the micropetrographic index and the quantification of microcracks. At this stage of the study, a new method to quantify microcracks was proposed. Basic physical and mechanical properties (e.g., specific gravity, dry and saturated unit weights, water absorption, effective porosity, P-wave velocity, uniaxial compressive strength and slake-durability index test) were also investigated on samples of all of the weathering grades where the sample preparation was available. The data obtained from the field studies suggest that dunite discontinuity spacing decreases from 577 to 1 cm and ranges from 487 to 1 cm for diorite. Schmidt hammer rebound test values (SHV) in the field were only obtained for fresh, slightly weathered and moderately weathered grades. SHV values range from 54 to 41 for dunite and 63 to 32 for diorite. The quantitative microcrack data obtained during the petrographic studies indicated that microcracks for diorite increase with increasing weathering, but a decrease was observed for dunite, which was related to the formation of serpentine minerals with weathering. Furthermore, with increasing weathering, the changes in the physical properties of dunite specimens exhibit a wider range than in the diorite specimens. Unconfined compressive test results for the rocks showed similar decreasing trends with weathering, but the dunite specimen started to slake by the highly weathered stage, where the diorite exhibited a considerable slaking by the completely weathered stage. This research concludes that the micropetrographic index and quantitative microfracture data provide useful input to recognize the weathering grades of studied rocks. It is also emphasized that serpentinization is the distinct process for dunite weathering and has a high impact on the weathering process, influencing physical and mechanical properties considerably. However, the increase of micro- and macrocracks is the dominant distinctive feature for diorite weathering.

Multivariate statistical approach to re-evaluate the slake durability index test (ASTM 4644–08)

The slake durability index test is designed to quantify durability of mainly weak rocks. The test is basically tumbling 10 pieces of rocks each weighing 40–60g for a two ten minute cycles in a water submerged mesh drum (2mm mesh size). Second cycle slake durability index values (Id2) are the percentage of the fraction of material retained in the drum after the second cycle test is completed. The difference in Id2 values between durable vs. non-durable mudrocks can sometimes be very small, due to the fact that fragments of material retained in the test drum can be larger than 2mm making the slake durability test inadequate to quantify durability of mudrocks. Therefore, it is necessary to investigate if other mesh sizes can better quantify durability and discriminate between durable and non-durable mudrocks. For this purpose, the grain size distribution of the material retained in the mesh drum after the slake durability test was sieved by #2 (6.3mm), #4 (4.75mm), #5 (4.0mm), and #10 (2mm) sieves. Multivariate/bivariate statistics was used to investigate which grain size fraction better correlates with the degree of disintegration. To quantify the degree of disintegration of the retained material, the fragmentation index is introduced. Another parameter used as a descriptor of the degree of disintegration is the sieved slake durability index. The results showed that the %>6.3mm size fraction has the highest control on both dependent variables. Discriminant analysis was also performed to identify which sieve size best discriminates between durable and non-durable mudrocks such as between shales and claystones/mudstones. Similar to the result of the linear regression analysis, the discriminant analysis showed that the %>6.3mm size is more sensitive than the %>2mm size to discriminate between the durable and non-durable mudrocks. We recommend sieving the retained material with the 6.3mm mesh and using a modified the slake durability index equation to better reflect the disintegration of mudrocks during the slake durability index test.

Estimating the uniaxial compressive strength of pyroclastic rocks from the slake durability index

Because the preparation of standard samples may not always be possible for weak or soft rocks, the prediction of uniaxial compressive strength (UCS) from indirect methods is widely used for preliminary investigations. In this study, the possibility of predicting UCS from the slake durability index (SDI) was investigated for pyroclastic rocks. For this purpose, pyroclastic rocks were collected from 31 different locations in the Cappadocian Volcanic Province of Turkey. The UCS and SDI tests were carried out on the samples in the laboratory. The UCS values were correlated with the SDI values and a very strong exponential relation was found between the two parameters. Since some data were scattered over the UCS values of 20 MPa, the correlation plot was redrawn for above and below the UCS values of 20 MPa, respectively. Very strong linear correlations were developed for two cases. Our concluding remark is that the UCS of pyroclastic rocks can be estimated from the SDI.