Weatherablity of clay-bearing rocks and reduction of their geomechanical properties with wetting and drying cycles, which determine with Slake-durability test, is one of the most important challenges in construction of structures on such rocks. However, many investigations, including the investigation carried out on this research; show that determining Slake-durability index of hard and strong rocks such as sandstones using the initiated method can provide useful information from geomechanical properties of such rocks. In this research, some Slake-durability tests have been carried out on some samples from Shemshak Formation and this index has been tested in different sandstones and clay-bearing rocks this formation. Meanwhile, the effect of the number of cycles, period of time the sample is rotating in water and angularity of the rock samples on the Slake–durability index as well as the relation between this index and uniaxial compressive strength has been investigated. This study shows that the as the number of cycles increased the Slake–durability index of sandstones (different types) and clay-bearing rocks decreased. Investigation on the effect of the time period the sample was rotating in water indicated that this factor has meaningful effect on the studied index of sandstone samples. However, the effect of the angularity of samples is quite considerable on the Slake–durability index, so that in the samples with Slake–durability index of above 98%, most of the angles are rounded at the end of the second cycle and there is a considerable differences between the Slake-durability index in the first and second cycles of the angled samples and rounded samples. But the differences are much reduced in cycles three to five. In clay-bearing rocks with Slake-durability index of lower than 98%, the effect of the angled nature on this index is more than sandstone samples, in cycles two and above. Investigation of the relation between the Slake-durability index and uniaxial compressive strength shows that the Slake-durability index is an acceptable and appropriate mean of estimating uniaxial compressive strength, especially in the sandstones.

A research program was conducted on different clay-bearing rocks selected from the Ilam, Sarpol-e Zahab and Tajarak regions (Iran) to predict their slaking characteristics. The new durability apparatus (nested mesh drums) separates disintegrated particles varying from> 25.4 to<2 mm as the drums were rotated. On the basis of the particle size distribution, the disintegration ratio (DR) was used to evaluate the rock durability. A concept was proposed to describe the rock slaking characteristics under the Slake durability test cycles, by using the difference in the DR values between the adjacent (DDR) and backward (N*) cycles. This allows the estimation of the rock durability as it is subjected to a larger number of test cycles, and hence the prediction of the effects of weathering processes. This prediction provides an effective approach when data are limited or inaccessible. Therefore, a new classification system is introduced for rock durability assessment. The test results show that the Gurpi-limey marls (G-2, G-3) and the Pabdeh-marly limestone (P-3) are classified as moderate to high durability rocks

This study investigates the relationship between Slake durability indices and geomechanical characteristics of five types of carbonate rocks situated in the west of Iran along the Doruod-Khorramabad highway. In this study, five types of limestone rocks were selected, including grey limestone (A), marly limestone (B, C, D), and sandy limestone (E). The geomechanical characteristics of the studied limestones were calculated based on the ISRM (1981) standard stimulations. Statistical approaches were executed to find the most influential geomechanical characteristics on Slake durability indices and to find an appropriate Slake durability cycle for interpreting rock behaviors. According to the simple regression analysis, the first and fourth cycles of Slake durability can provide adequately good information for initial engineering/design works. Also, the correlation coefficients demonstrated nearly constant change after the fourth cycle. Geomechanical parameters, like Schmidt hammer and dry density, showed the highest correlation with the fourth Slake durability cycle (R =0. 98). On the other hand, uniaxial compressive strength revealed a poor correlation (R = 0. 49) with this cycle. Apart from estimating the 4th durability cycle from geomechanical properties, it is possible to calculate the second to fourth cycles of Slake durability using the results of the first durability cycle (R = 0. 99–, 0. 94). Consequently, a multivariate equation was developed based on water absorption, Schmidt hammer, effective porosity, and modulus of elasticity with R2=0. 89 using the best subset regression method.

Slake durability of rock is an important engineering parameter for evaluating deterioration rock in chemical and physical agents that related to mechanical properties rock. The main purpose of this study is to assess the influence of the number of drying and wetting cycles under variable pH conditions and controls of mineralogical composition on durability. For this purpose, five different types of tuff were selected from different parts in north Qazvin city. The samples were subjected to multiple-cycle Slake durability testing with different pH values solution. Also the Slake durability tests in saturated condition on samples, petrographical analyses and basic physical-mechanical test were performed. In addition, to assess the influence of mineralogical composition on durability, the mineral contents of the original material and the material passing from the drum of the Slake durability apparatus after fifteen cycles were also determined by XRD analyses. It was concluded that the Slake durability of tuff is independent of the pH in acidic solution circumstances. Mineralogical composition, fabric and weathering rate are considered to have a greater influence on the Slake durability of tuff. A strong relationship between the point load strength and the fifteenth-cycle Slake durability index is found in the rock types studied.

Predicting the long-term durability of rock in the construction of breakwaters is crucial for their safe and economic operation, but remains challenging. Here, we report on the application of Machine Learning models to such prediction. We developed a database of physical and mechanical properties of rocks from 35 rubble mound breakwaters on the Caspian Sea, Oman Sea and Persian Gulf coastlines of Iran. Properties include uniaxial compressive strength, point load strength, Brazilian tensile strength, aggregate impact and aggregate crushing values, Los Angeles abrasion, porosity, ultrasonic wave velocity, density, sodium sulfate soundness and Slake durability index, together with petrophysical data. These data were analysed using the four supervised machine learning (ML) models of random forest (RF), support vector (SV) machine, gradient boost (GB) and k nearest (KN) neighbor. Model performance was assessed using RMSE computed using predicted and measured values of Slake durability, and R2 of the linear regression of the predicted and measured Slake durability values. The results indicate that the random forest (RF) models perform best, especially for igneous rocks: for both saturated and oven dry igneous rocks the RF model produced prediction errors of under ±0.6%, and R2 was unity to five significant figures. We conclude that ML techniques are robust methods for predicting the Slake durability resistance of rock material used in the construction of breakwaters.

durability is a significant parameter in engineering geology and it shows the extent of the degradability of rocks as the result of mechanical and chemical breakdowns. This phenomenon is closely linked to the composition, porosity and texture of rocks. To understand the relationship between the chemical composition of rocks and their durability the mineralogical properties of the rocks along with durability tests under both acidic and alkaline pH environments were determined. Five samples of limestone and three samples of marl were analyzed. The results revealed that rocks containing high levels of CaCo3 were affected in the acidic conditions while rocks containing high levels of SiO2 were not affected by variance in the pH of the environment. These second groups of rocks were more dependent on the texture of their constituent minerals. Keywords: Slake durability index, pH, Mineralogical properties,

A significant portion of the Karaj Formation in Alborz region is made of tuffs. Tuffs are readily used as construction material in various types of structures in Tehran and its neighboring provinces. The current research studies the petrographical characteristics as well the physical and mechanical characteristics of tuff samples collected from the Karaj Formation in the northern parts of Tehran, Alborz, and Qazvin provinces. In order to study the effect of freezing and thawing on the tensile strength, an 80-cycle freezing and thawing test was performed on the samples. The Brazilian tensile strength was evaluated during difference cycles. Subsequent to the freezing and thawing test, during cycles 15, 30, and 60, a Slake durability test was attempted for five cycles. Based on the observed data, the long-term durability of tuffs was evaluated using the decay function model. The result yielded from the parameters of decay function model (decay constant and half-time) during the Slake durability test were compared to those of descriptive observations during the experiment. The results indicate that the Slake durability indicator cannot be used to evaluate the decay constant and the half-time of the samples being studied. The decay constant and the half-time yielded through the Brazilian tensile test at different cycles of the freezing and thawing experiment indicate that the decay rate of the samples were not uniform throughout samples. It is recommended, here, that the varying rate of decay should be taken into considerations when samples are chosen for specific applications.

Rocks subjected to cyclic weathering processes such as freeze – thaw and salt crystallization may lose their integrity and be deteriorated during time. By increasing in cycle numbers and their intensity, the rate of deterioration will be increased; however, this rate is not the same for different rocks. In this study long term durability of upper red formation sandstones against freeze – thaw and salt crystallization were evaluated using decay function model. By using this model it is possible to obtain some meaningful parameters and determine deterioration characteristics of rocks. For this purpose, 9 specimens of sandstones (specified by A, B, C, CG, S, S1, Tr, Min and Sh) were collected from different parts of the studied area, then their physical and mechanical characteristics including unit weight, effective porosity, water absorption, P-wave velocity, Brazilian tensile strength and point load strength were determined. In order to assess the effect of freeze – thaw and salt crystallization on physical and mechanical characteristics of sandstones, 60 cycles of freeze-thaw test and 20 cycles of salt crystallization test were performed. Then their effects on tensile strength and point load strength were recorded in different cycles. Also, decay constant and half-life of these parameters were calculated. In addition, Slake durability index test was performed in three different cases such as standard (wet state), freeze-thaw (performing test on samples subjected to freeze-thaw action) and salt crystallization (performing test on samples subjected to salt crystallization action). Obtained Slake durability index from different cases were used to estimate decay constant and half-life parameters. Bye using these parameters (tensile strength, point load strength and Slake durability index test) and applying decay function model, long term durability of sandstones against freeze-thaw and salt crystallization were evaluated. Results show that decay constant and half-life can be used in engineering practice for determining long term durability without consuming more cost and time. Also this model indicates that the disintegration rate of sandstones is different and the half-lives obtained from three parameters are different for each sandstone.

Strength and durability of sandstones and also natural condition effects on these properties, is one of the most important parameters which have to be taken in to consideration in engineering constructions. In this study, the effect of freeze – thaw and salt crystallization phenomena on strength and durability of upper red formation sandstones collected from southern part of Qazvin province was investigated.9 specimens of sandstones (specified by A, B, C, CG, S, S1, Tr, Min and Sh) were collected from different part of studied area, then their physical and mechanical characteristics were determined. In order to assessing the effect of freeze – thaw on physical and mechanical characteristics of sandstones, 60 cycles of freeze-thaw test was performed. Also in order to investigate the effect of salt crystallization on strength of studied sandstone, sodium sulphate crystallization test (100% weight solution of Na2SO4) was carried out in 20 cycles. Physical and mechanical characteristics of studied sandstones such as point load index, Brazilian tensile strength, wave velocity (Vp) and weight loss were determined after different cycles. For assessing the effect of freeze – thaw and salt crystallization phenomena on durability of sandstones, Slake durability test was performed on specimens subjected to mentioned processes and changes occurred in Slake durability index in 15 cycle were investigated. Based on results obtained from current study, it could be concluded that in comparison to freeze – thaw, salt crystallization can considerably reduce the strength and durability of sandstones and deteriorate them. Also it was found that index tests such as point load index, Brazilian tensile strength, wave velocity (Vp) and weight loss can predict the behavior of sandstones in different cycles of freeze – thaw and salt crystallization tests.

One of the most important issues in the design and implementation of engineering structures is to evaluate and investigate their durability against processes of consecutive wear, wet and dry. The durability of rock is resistance against chemical and physical weathering, the shape, size and status of the initial appearance in a long time and environmental conditions prevailing in the rock, hence it is important to evaluate the durability of rock. Since the device of standard durability (Franklin & Chandra, 1972) designed to evaluate and investigate durability of soft and argillites rocks. So, appears to be essential to design a durability device, which can evaluate hard rocks. For this purpose, Researchers of the Department of Geological Engineering, Tarbiat Modares University, durability device as «large-scale durability device» was designed and built which the length and diameter of the device, is 6 and 4.3 times standard durability device, respectively, and needs 10 samples with weight of 400 to 600 g. In order to investigation the applicability of this device for hard rocks durability, we selected 17 building rocks samples of the igneous, sedimentary, metamorphic and pyroclastic rocks. Then their mineralogical, physical and mechanical properties were investigated. More, experiments of standard and large-scale durability up to 15 cycles were performed and data obtained were analyzed. The results show that, the large-scale durability device than standard durability, have more applicability for evaluating the durability of hard rocks.