فهرست مطالب mohammad reza nikudel

The Ilam Formation has a special place in the oil industry as one of the most important oil reservoirs and as a construction site in projects, so knowing its engineering geological characteristics is very important.In order to comprehensively investigation of the Ilam formation, the type section of the formation was studied in Ilam, Lorestan and Kermanshah provinces. Based on the studies of 110 samples, 7 types of microfacies were identified and were classified in 4 groups Mudstone, Wackestone, Wackestone-Packstone and Packstone by Dunham method. The physical properties of rocks including density, porosity, water absorption and p-wave velocity and mechanical properties including uniaxial compressive strength and point load index were measured.The results show that the average porosity and water absorption of mudstone samples are higher than the other types of rocks tested, which is due to the finer grain of the texture. P-wave, point load index and uniaxial compressive strength in Packstone samples are higher than other types of samples, which is due to the presence of more grains in the texture and as a result its higher strength.The results of the statistical tests show that there is a statistically significant relationship between the independent variables and the dependent variable. In addition, the relationship between point load index and uniaxial compressive strength was linear. The correlation coefficient of uniaxial compressive strength with porosity and point load index is higher than other parameters, and as a result, they provide a suitable estimation of the strength of Ilam limestones.

This study compares rock porosities measured using petrographic image analysis (PIA) and saturation-buoyancy (SB) methods. To this end, the fresh block samples from sandstone and limestone were collected from Upper Red and Asmari Formations, respectively. Next, cylindrical core specimens from those were prepared using a coring machine. Afterward, the porosity values of sandstone and limestone samples were measured using PIA and SB methods. In the next step, the physical and mechanical properties of samples, including water absorption (W), P wave velocity (PWV), uniaxial compressive strength (UCS), Young’s modulus (E), point load strength index (PLSI), and Brazilian tensile strength (BTS), were determined. Results showed that PIA underestimates the porosity in both rocks. These conservative results can be attributed to the incomplete filling of micropores with blue-dyed epoxy resin in sandstone cement and limestone matrix or petrographic microscope limitation to differentiate micro-pores in cement and matrix. Furthermore, results demonstrated that SB in upper red sandstone has a good correlation with W, E, and BTS and a moderate correlation with PWV, UCS, and PLSI. Besides, porosity of limestone samples showed strong relation with W, PWV, and BTS, while UCS and E data versus porosity showed a scattering pattern. Finally, a strong relation was established between PIA porosity and UCS, E, and PLSI, a poor correlation was established in the cases of W, PWV, and BTS. Overall, PIA is a strong method for investigating the interior pore system of rocks, especially isolated pore spaces, although it underestimates rocks porosity compared to the SB method.

The central Alborz structural-sedimentary area in the middle part of the Alborz Mountain Range has endured geological events from the Precambrian to the present era, and contains numerous geological structures and formations. Among these, sandstone formations also have a significant expansion. In this research, 6 different sandstone formations were sampled in 2 locations and tested to determine their physical and mechanical characteristics. In general, in the sandstone formations of central Alborz, top quartzite has stronger mechanical parameters than other formations. Shemshak Formation has the lowest mechanical parameters among the selected formations. Based on regression analysis, the conversion factor of PLT, BST and CPI parameters to unconfined resistance or UCS showed 20.6, 6 and 20.40 respectively with R2s of 0.75, 0.90 and 0.78. In terms of the Cerchar Abrasivity Index (CAI) as an index that can show the amount of abrasion, top quartzite has the most abrasiveness, which is due to its lithological composition. This sandstone formation is placed in the category of stones with high abrasive ability, and Shemshak Formation has the lowest Cerchar index among the formations and is placed in the group of stones with extremely low abrasiveness.

Bio-improvement has been identified as an environmentally friendly method, Microbially Induced Calcium Carbonate Precipitation (MICP) is the predominant technique in this domain. The four main methods introduced for MICP are the injection, surface injection or flow-through, immersion, and mixed methods. Among these, the injection and the flow-through methods hold particular significance. In this study, the efficiency and performance of these two methods were investigated in soils with different relative densities and varying volumes of bacterial suspension injection.To assess the efficacy of these methods, various tests including optical density, urease activity, permeability, uniaxial strength, calcium carbonate pericipitation percentage were conducted. The flow-through method, with its easier implementation, absence of the need for special equipment, minimal reduction in permeability, more uniform dispersion of the resulting cement, and the ability to achieve comparable strength to the injection method when using an injection volume equal to the pore volume in high relative density, stands out as the more suitable and economical approach for improving sandy soils. Despite its cost-effective implementation, the flow-through method necessitates more injection cycles, particularly in the injection volume of two-thirds and one-third of the pore volume, to achieve the same strength as the injection method. This aspect diminishes the economic difference between improvement using the injection method and the flow-through method in laboratory. This aspect diminishes the economic difference between improvement using the injection method and the flow-through method in a laboratory conditions.

The current study evaluates ordinal logistic regression (OLR) for assessing collapse sensitivity classes of loess soils. Collapse sensitivity (Is) is the critical parameter to predict pseudokarst sinkholes occurrence in Golestan Province in northeastern Iran. A database containing 62 records of soil's physical and mechanical properties is used in this study. By performing oedometer tests, the parameters of collapse coefficient, the time required for 90% settlement (T90%), and collapse sensitivity were determined. To gather this goal, a database was prepared based on experimental datasets, consisting of ten inputs (grain size analysis, porosity, initial water content, precipitation, climate, liquid limit, calcium carbonate, vegetation, and degree of soil saturation) and one output (collapse sensitivity classes). This task is complex due to the difficulty of preparing and carrying out such experiments in a laboratory. Using OLR, the probability of soils being placed in classes with severe, moderately severe, moderately, and slight sensitivity was estimated. This study showed that the OLR method could correctly distinguish more than 70% of different categories. Experimental data obtained from Semnan, Sarakhs, and Mashhad areas, has shown the accuracy of the proposed OLR model.

Central Alborz Zone (CAZ) comprises a range of industries and a high concentration population (about one-fourth of the country's population), essential to provide material resources and create the necessary infrastructure for this massive population. The CAZ has a large variety of rock formations and facies, which causes extensive expansion in rock materials and resources. One of the major materials in the CAZ is the existence of a wide variety of carbonate rocks (Elika, Dalichai, Lar, Tizkuh, Ziarat, and Kond formations). This study aims to investigate the geological and engineering geological characteristics of six carbonate formations in the CAZ and to classify carbonate rocks based on their material and their performance in asphalt mixtures. Therefore, by sampling these formations and performing various lithological and engineering geological experiments, six studied formations have been classified, and have been used to evaluate their performance in asphalt mixtures. Selected formations include Elika, Dalichai, Lar, Tizkuh, Ziarat, and Kond. The studied carbonate rocks were classified based on the lithology and performance of their asphalt mixtures in fatigue and cracking test. This classification includes the best performance to the weakest performance, respectively, including Mudstone (Elika Formation), Bioclast Grainstone (Kond Formation), Bioclast Packstone (Dalichai Formation), Bioclast Packstone (Tizkuh), Packstone-wackestone (Ziarat Formation) and Dolostone (Lar Formation).

Engineering properties of soils and the 3D modeling of geological formations are widely used in site investigations and the preparation of geological hazard maps. The present study was conducted to characterize the engineering geological properties of the young surface alluviums of the Gorgan city (Iran) to a depth of 25 m and 3D modeling of their geology using boreholes data. To this end, after determining the location of the available boreholes on the aerial map of Gorgan, four hypothetical cross-sections were considered in the North-South and East-West directions. Then, the borehole data were marked on each section and their 2D geological cross-sections were manually drawn using correlation of the similar layers. In the next step, by expanding the information of these sections, a 3D geological model of Gorgan city was prepared using a conceptual-observational method. According to the evidence from the boreholes and field observations, the depositional environment of Gorgan alluviums was an alluvial fan created by the Ziarat River. Additionally, in terms of engineering characteristics of alluviums, the Gorgan subsurface soils can be divided into four engineering units, including upper clay unit (UCU), middle gravel unit (MGU), lower clay unit (LCU), and sandy unit (SU), which share the same engineering characteristics. Finally, the results of tests performed on samples from different depths were employed to calculate the engineering geological characteristics of each unit, including Atterberg limits, compressibility, undrained shear strength, and drained shear strength parameters.

Joints and cracks are an integral part of rock structures. When load applied to these structures, growth, and interaction of the cracks lead them to failure. This aspect is particularly crucial in cyclic loading because failure occurs at stress levels lower than the yield point due to the fatigue process. This research aims to study the growth and interaction of the cracks in the fatigue process by the fluorescence thin section method. At first, different stages of fatigue for granite rock were determined, then samples loaded up to each stage. Later, the physical, mechanical, and crack properties of the samples were investigated. The results show that physical and mechanical properties declined by increasing the number of cycles. During the first stage of fatigue, crack initiated at a high rate, and in the second stage, the increasing rate descended, and energy mostly consumed to increase the length of the cracks. In the last staged, which is the failure stage, the rate of crack initiation increases again and forms a complicated network of cracks, which leads the sample to failure. Among the constituent minerals, feldspar exhibits the highest crack density, and biotite shows the lowest density of the cracks.

Artificial stone is a mixture of natural aggregate and additives such as industrial gums (resin), cement and other polymer materials. The purpose of this study is to compare the physical and mechanical properties of artificial stones made in different conditions, resins and aggregates. To achieve these goals, synthetic rock samples were made with polyester and vinyl ester resins and granite, lime, silica granules and lime-silica composites, with the existence and lack of vacuum and pressure during the fabrication of artificial stones. To determine the physical and mechanical properties (Brazilian Test, Point Load Test, Uniaxial Compression Test), artificial stones have been tested. Based on experiments, artificial stones made with vacuum and pressure systems have more favorable physical properties and undesirable engineering characteristics than coarse specimens made in completely manual conditions without vacuum and pressure systems. The specimens made with vinyl ester resin have more axial compressive strength than the other specimens and their fracture type is elastic - fracture but the specimens made of polyester resin without paying attention to aggregate type, show the elastic - plastic and creep behevior. Increasing of the resin percentage in artificial stones made of limestone, increases tensile strength but does not have a positive effect on granite. The results show that all the resistive properties of artificial stones are controllable. Also the mixing plan and ratio of mixing percentages are the most important principles in the strength and resistance of the artificial stone and are flexible for any use and taste.

Concrete is the most widely used materials in construction throughout the world. Among its properties, strength is the most important, controlled with utmost care by engineers and designers. Concrete is made of different materials: aggregate, water, cement and admixture. Aggregate occupies approximately 75% of the concrete mass; as a result it definitely has an important role in the properties of fresh and hardened concrete. In this research, in order to study the effect of different aggregates in sulfur and conventional concrete, 7 types of rock have been selected including River material, Granite, 2 types of Limestone, Coquina , Travertine and expanded clay. Having designed the machine, the aggregate was prepared from these rock types; then the physical and mechanical characteristics of the samples were determined. After selecting an appropriate mix design which could be applied to both types of concrete, samples were prepared and investigation showed that weak aggregates which are not used in conventional concrete, can, with changes in the mix design, be used in sulfur concrete and provide the needed strength(Coquina that gained 17.6 MPa in conventional concrete reach to 43.6 MPa in sulfur concrete). Furthermore, texture and porosity play an important role in sulfur compared to conventional concrete.

The deformation and failure properties of the loaded rocks are divided into different stages based on cracks' formation and growth. The different damage stress thresholds separate these stages. Considering the damage stress thresholds as a material property, geological properties of rocks can affect the damage stress thresholds. In this research, damage stress thresholds were identified for granite and diorite in the uniaxial compressive loading test with the help of the Acoustic Emission test (AE). Then fluorescence thin sections were prepared from the samples loaded to each damage stress threshold to investigate the effect of the mineralogy and the grain size. The results show that strong minerals increase the stress damage thresholds level due to the high cracking resistance. Furthermore, by decreasing the mean grain size, a better interlocking between the grains is created, and the number of grain boundaries increases. Therefore, the applied force has a higher surface to distribute. Consequently, minerals are less affected by the applied force; their crack density reduces, and crack initiation stress threshold increases.

Artificial stone is a mixture of natural aggregate and additives such as industrial gums (resin), cement and other polymer materials. In this research, artificial stone with additives and two resins (vinyl ester and polyester resin) in order to determine the strength and type of use, mixing plan, 84% rock, 10% resin and 6% additive completely manually without the need Vacuum and pressure system was built. Artificial rocks made with additives (glass fiber, carbon fiber, plastic), and three granite granite stones (Alamut, Sefid Tekab and Nehbandan) are used to determine the physical and engineering characteristics (Brazilian Test, Point Load Test, Uniaxial Compression Test and Ultra Sonic Test) have been tested. Based on experiments, artificial stones made of precious stones, a resin of wilin ester, glass fibers, have the highest compressive strength of single axis and borehole. However, carbon-fiber samples have a tensile strength of 28% compared to glass fiber-reinforced glass samples. The samples made with plastic have the least porosity between the samples of synthetic stones. According to the above results, in environments affected by pressures, high-strength reinforced rocks (glass-fibered samples), in tensile-induced environments; high tensile strength artificial rocks (samples made With carbon fiber) and on sidewalks made of synthetic stones made of plastic due to low porosity.

This study aimed at evaluating the effect of calcic aggregates of engineering geological properties on the artificial stones properties, non-resin cemented and then, to make a comparison between the engineering properties of artificial and natural stones. To investigate the effect of calcic aggregates properties on artificial stones, seven samples of building stones including black limestone, three samples of marble (Chinese stone, marble and crystalline marble) and two samples of travertine and onix were used. Engineering geological properties of the samples were then determined. In the next stage, after designing mould for constructing artificial stones, aggregates with the same grading and mixture design were provided. Then two samples including coarse and fine grained artificial stones were made for all of the mentioned aggregates under the same vibration, pressure and vacuum conditions. Next physical, strength and durability tests were conducted, and the obtained results were compared. The results of engineering parameters showed that Hojjat Abad travertine artificial stones have similar engineering quality to own natural stone and Crystaline Marble and Turan Posht travertine artificial rocks have about 11 to 32% increase in quality but Chinese stone, Black limestone, onix and marble have a 6 to 33% lower quality than own natural stone. However, the samples made of other stones in view of the compared parameters related to artificial stones have lower quality than natural stones; however, they are placed in the acceptable range as building materials.

The area of Charousa and Lendeh in the Kohgiluyeh and Boyer-Ahmad province in southwestern Iran is geologically part of the folded Zagros. In this area, the core of the Kuh-e-Sefid and Sartal anticline of the Ilam-Sarvak limestone are the main high altitudes of the region. At these altitudes the scar of large landslides and evidence of deep seated gravitational slope deformation are visible. The largest of these are the Almor landslide in the Sartal anticline with an approximate volume of over 600 million cubic meters. In this study, the evidence of deep seated gravitational slope deformation of these anticlines has been investigated and the causing factors for Almor landslide have been determined. To investigate of this issue, a combination of geological field survey, image processing studies, and laboratory studies of rock mechanics and soil mechanics were used to prepare preliminary data. This data are processed and analyzed by a combination of kinematic analysis, limit equilibrium sensitivity analysis, and finite element numerical modeling. Finally, a three-dimensional geological model is proposed to illustrate the proposed mechanism for this landslide. According to this study, a combination of deep seated gravitational slope deformation, along with wedge failure and three hinge buckling, was the causes of this avalanche.

Various standards and criteria are existed regarding rubble mound breakwaters. Based on engineering material properties used each of them have own classification . Where as  these types of breakwaters are mainly made by rock material, knowing their  engineering properties such as durability and deterioration and destruction against predominant condition in marine environments is vital in order to preparation of proper classification system. Iranian rubble mound breakwaters in Persian Gulf, Oman Sea and Caspian Sea are mainly designed and made based on regulations, standards and criteria of other countries such as, America, Britain, Japan and Netherland. Using of these standards caused limitations such as the mismatch of the selected stone with the given standards and operating costs are increased. This paper introduces national and international criteria in order to select rock used in break waters. In the following with Concentration, on national criteria, most important indexes of these criteria presented for each type of stone.

The durability of concrete is affected by various factors including its ingredients, workmanship, environment, working life, and so on. The alkali reaction within the concrete can shorten its lifespan due to the expansive pressure build up and cracking caused by the deleterious action of alkali reaction by-products. The alkali reaction is a gradual reaction that can happen between the alkaline pore solution of the concrete and various types of aggregates. Understanding the behavior of the aggregate, as the main reactive component, is thus essential in understanding of the reaction mechanism, reducing the alkali reaction potential or even preventing it. Not all aggregates are susceptible to alkali reaction. Therefore, detecting susceptible aggregates and selecting the ones with low levels of reactive materials, can eventually help to minimize and mitigate alkali reaction problems. The aim of this research was to assess the susceptibility of four commonly used aggregates in constructing projects: Granite, Rhyodacite, Limestone and Dolomite. The study was performed under accelerated conditions in accordance with the ASTM test method C1260 and ambient condition (room temperature).specimens were analyzed using Scanning Electron Microscopy (SEM),X-ray Diffraction (XRD) and Light Microscopy. Limestone and Rhyodacite aggregates, were found to be susceptible to expansion reaction.

Abstract Abstract All of the engineering structures construct on the ground, thus it is necessary to investigate and evaluate the geological engineering characteristics and probable geo hazard like karstifiaction potential of the construction sites. Hydraulic structures are from this structures that because of their immediately relation to the ground, the importance of this investigation is more noticeable. The constructed hydro structure on the carbonate rocks maybe confront to damage because of solution, enlarging and spreading of joints. This phenomenon may led to karstification and large seepage amount of water from foundation and inefficiency of dam. This article discusses about the rate of extension of the joints in different velocity and temperature regard to their original opening. The evaluation is obtained by experimental tests on rock cores of Khersan1 dam site. The results show that there are many factors that affect joint behavior against water flow; these factors are primary opening of joints, flow velocity, temperature, acidity and etc. In this research behavior of the joints with different opening in different temperature has been evaluated. The results show direct relation between extension of the joints and decreasing of the temperature and indirect relation between joint extension and their primary opening. Also the results show that filling and washing out of the joints in identical condition is controlled by flow velocity and their primary opening as the joint with opening of 0.3 mm shows washing out and filling against high and low velocity respectively. 

Dispersivity is a physico-chemical phenomenon whereby clay soil particles lose their cohesion in the presence of water and repel each other, so that the particles become suspended in water and easily washed with very little energy from the environment. Potential dispersivity in a given soil depends on several factors, including: type of clay minerals, pH, organic matters, temperature, moisture percentage, type and concentration of ions existing in the soil pore water and the characteristics of eroding fluid and usually there are high amounts of sodium cation. Soil dispersivity evidence can be alluded to the development of erosional shapes on steep and flat areas; since these erosional shapes were observed upon the Gachsaran formation in Masjed Soleyman petrochemical site, so sampling was carried out from different parts of the site in order to assess the causes of erosion. Then, by performing physical and chemical tests as well as the tests to characterize soil dispersivity, it was observed that the amount of sodium cation is low and soil itself is non-dispersive. By observing the gypsum mineral, voids and free spaces available in manual and microscopic samples, their gypsum content was determined. Again, by its relation with field observations, it was revealed that erosion shapes induced by leaching, dissolution and ultimately the soil to be hollowed in the result of gypsum mineral presence that has been contributed in developing a kind of mechanical erosion in the region.

Understanding of the geological characteristics of artificial stone is of particular importance. Appearance, size and dimensions, specification of particle surface and minerals forming aggregates are among the characteristics of rock materials that affect the homogeneous and cladding environment. Volume variations, water absorption, resistance to atmospheric agents and wear resistance are the most fundamental features of engineering stone in artificial stone. In this research, to investigate and compare the resistance properties (Uniaxial Compression, Brazilian, Point Load, Ultra Sonic) and the physical properties of artificial stones made with additives (polyester resin, vinyl ester resin, glass fiber and aggregate type) with three granite samples, we will cover the Alamut granite, Takab granite and Nehbandan granite. The results of the study show that the glass of fiber glass samples compared to non-woven glass made of resin and aggregates, has more 15% of tensile strength, 14% of uni - axial compressive strength and 12% of the point load index. As well as, resistance of samples made with a leaden resin is 1.64 times more than polyester resin specimens. Based on this study, the mixing plan and percentage ratio combination is the most important principle in the strength and strength of artificial stone

Artificial stone is a mixture of natural aggregate and additives such as industrial gums (resin), cement and other polymer materials. In this research artificial stones with different additives and resins were designed to achieve high flexural capacity with mixing design, 84% aggregate, 10% resin and 6% additive completely manually without vacuum and pressure system. FESEM images were taken from specimens to determine fine cracks, elements, manufacturing atoms, weight percentages, and how to add and interconnect the additives used in making artificial rocks. To determine the ductility and evaluation of the quality of artificial rocks by their ability to withstand cracks or other surface roughness over a continuous bending period, artificial rocks made with additives (glass fiber, carbon fiber, polyester resin And vinyl ester) Three-point bending test Based on the three-point bending test, the sample made from wilin ester resin and the carbon fiber, had the most flexural strength and a sample made from wilin ester resin and the glass fiber tolerated the most strain during bending. Also, the type of fracture and cracks in the reinforced rocks are brittle and flexural respectively, and are ductile and shear-bending in rocks without reinforcing.

Specifying the soil types and profiling the subsurface soil layers are the excellent examples of CPTu test potentials. In this research, the capability of CPTu test for specifying subsurface soil layers and classification of the sediments in Urmia Lake is investigated. According to previous studies, the sediments of Urmia Lake are commonly fine grained and soft deposits with organic materials. To evaluate the geotechnical parameters of these sediments in Urmia Lake Bridge site, CPTu test was performed and soils were classified applying the results of this test. The results showed that the sediments are mostly composed of clay and silt. To verify the results of CPTu tests for soil classification, the outcomes were compared with the logs of the boreholes and the results of laboratory tests. Comparisons and analysis of findings showed high consistency between the three groups of results; CPTu, boreholes logs, and laboratory tests. Thus, CPTu test can be used, with sufficient confidence and accuracy, to specify and classify the soft soil in lacustrine environments.

Engineering characteristics of different soil mixture are influenced by each of components. In this research the influence of nano bentonite on engineering behavior of nano bentonite- sand mixture (NBS) are investigated.
An experimental study involving, compaction test, direct shear and permeability tests was carried out to investigate mechanical behavior and hydraulic conductivity of NBS. different nano bentonite- sand mixtures were prepared. The maximum dry unit weights and corresponding optimum water contents were obtained. According to the results of direct shear test, the highest cohesion (c) and highest internal friction angle (φ) was selected and the permeability tests were performed in 4 states of compaction, include 90, 100, 110 and 120 % maximum dry unit weight.
The results show that permeability decreases by increasing nano bentonite and compaction degree. The lowest permeability is related to sample with 9% nano-bentonite. The cohesion increases by increasing nano bentonite content till 5%, but after that the internal friction angle is increases. The effect of nano-particles is more than compaction on permeability.

The relation between Soil compression degree and the permeability changes during static compression process is one of the important factors for understanding hydro mechanical soil behavior. In this research such relationship has been closely studied. Three soil samples have been selected from loess soil (wind deposits) that extended widely in Golestan province, north eastern Iran. In first step, a test apparatus must be design to measure the soil compression degree and permeability value simultaneously. The designed apparatus is able to set high porosity soil sample in a test cell, measurement static compression force, compression degree and the value of permeability at different stages of soil compression process. In addition, soil structure can be observed during the test through a camera attached to the test chamber. The results show that soil type and primary structure affect soil compression behavior. Result of Permeability tests of loess soil shows that there is logarithmic relation between void ratio and permeability and its general form of experimental relation is proposed in this research.

The durability of stone against environmental degradation factors is one of the most important issues related to stone selection for use in engineering structures, in particular stone stones. The crystallization of soluble salts is one of the most important weathering factors in nature, which can affect the mechanical properties of rock (such as uniaxial compressive strength and Brazilian tensile strength) and, over time, can decay and reduce its durability. In this research, a physico-mechanical parameter has been introduced that can assess the mechanical properties of rocks and thus their durability against salt weathering with accurate accuracy. To achieve the research objectives, 15 travertine samples were selected from different mines in Iran. Travertine samples were prepared to determine the physical properties (water absorption, mean pore diameter) and mechanical properties (uniaxial compressive strength and Brazilian tensile strength). Then, the physico-mechanical parameter was calculated, based on the combination of water absorption, mean diameter of the pores and mechanical properties. By performing bivariate regression analysis, the relationship between physico-mechanical parameter with uniaxial compressive strength and Brazilian tensile strength after the salt weather test was investigated and the most suitable relationships for estimating the durability of the samples using a physico-mechanical parameter against weathering is presented. The results show the correct accuracy of the physico-mechanical parameter for estimating the durability of the studied samples. As a result, the Physico-Mechanical Parameter avoids performing a salt crystallization test, which is time-consuming and expensive.
The durability of stone against environmental degradation factors is one of the most important issues related to stone selection for use in engineering structures, in particular stone stones. The crystallization of soluble salts is one of the most important weathering factors in nature, which can affect the mechanical properties of rock (such as uniaxial compressive strength and Brazilian tensile strength) and, over time, can decay and reduce its durability. In this research, a physico-mechanical parameter has been introduced that can assess the mechanical properties of rocks and thus their durability against salt weathering with accurate accuracy. To achieve the research objectives, 15 travertine samples were selected from different mines in Iran. Travertine samples were prepared to determine the physical properties (water absorption, mean pore diameter) and mechanical properties (uniaxial compressive strength and Brazilian tensile strength). Then, the physico-mechanical parameter was calculated, based on the combination of water absorption, mean diameter of the pores and mechanical properties. By performing bivariate regression analysis, the relationship between physico-mechanical parameter with uniaxial compressive strength and Brazilian tensile strength after the salt weather test was investigated and the most suitable relationships for estimating the durability of the samples using a physico-mechanical parameter against weathering is presented. The results show the correct accuracy of the physico-mechanical parameter for estimating the durability of the studied samples. As a result, the Physico-Mechanical Parameter avoids performing a salt crystallization test, which is time-consuming and expensive

Rock powder, aggregate, a small amount of cement or resin and other chemicals are used for producing artificial stone.In this research, limestone aggregates (in the size 0.075 of 19 mm), rock powder and white cement were mixed and wetted and then, they were compressed under three physical processes including vibration, vacuum and pressure in a cubic mold. The aim of this study is investigating the effect of pressure and vacuum on the improvement of physical Characteristics of produced artifitial stone. As well as comparing the characteristics of artificial stone which made with two natural stone, including marble stone (primary rock in the production of aggregate) and travertine (porous and light weight stone). The results showed that the artificial stones have similar engineering characteristics to travertine stone. Therefore, a mixture of cement-aggregates can be used to make molded artificial rocks with acceptable engineering characteristics.