Journal of Engineering Geology

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The main objective of this research is to provide information about the effects of mineralogical characteristics of aggregates on concrete properties. Crushed aggregates were selected with different petrographics from different resources. Aggregates such as, Marble, Dolomite, Tuff, Granite, Genasis, Basalt, Andesite, Lumashele, Sand Stone and Diorite which have different chemical, physical and mechanical properties were used in this study. The results of the study showed that physical and mechanical properties of minerals control properties of concrete and undesirable properties of concrete influenced with which of mineral. Also, the results indicated that aggregates with flaky and elongated minerals subjected to weathering have a great effect on undesirable properties of concretes. The highest uniaxial compressive strength (33 MPa) at 28 curing days was measured in the specimens prepared with dolomite aggregates while the lowest strength (13 MPa) was measured in the specimen prepared with lumashele aggregates at the same age.

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 In this research, prediction of concrete strength containing different aggregates using Non-destructive (Ultrasonic) testing through Artificial Neural Networks was carried out. For this purpose, aggregates with different properties were selected from the quarries, and then their destructive and nondestructive properties were obtained in laboratory. The significance of this research, using different aggregates with physical, mechanical and chemical properties also used two different test methods, such as Non-destructive static and dynamic testing, which are respectively uniaxial compressive strength and compressive wave velocity. Thus, this model includes various types of samples and the prediction model includes static and dynamic tests. The results showed that the use of artificial neural networks not only increases the accuracy, but also it reduces costs and time.

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Introduction
The general failure mechanism of soil element in geotechnical structures is shear failure under static and dynamic loads. Therefore, assessment of soils’ shear strength parameters is very crucial in the performance of geotechnical structures, especially in slope stability. Tavakoli Mehrjardi et al. (2016) showed that by increasing soil grain size in unreinforced soil masses, bearing capacity of foundation increases due to increasing shear strength parameters of soil mass. Furthermore, Tavakoli Mehrjardi and Khazaei (2017) found out that generally, for all reinforced and unreinforced conditions, cyclic bearing capacity was enhanced by increasing the medium grains size of backfills. Taking into account the deficiency of studies on the shear characteristics of soil, a series of large direct shear test have been carried out to investigate and to compare effects of the soil’s physical properties such as aggregate size and relative density, besides of normal stress, on the shear characteristics of the backfills.
Material and Test Program
In this study, three types of uniformly graded soils as fill materials with the medium grain size (D₅₀) of 3, 6 and 12 mm were considered. These soils are classified as SP and GP in the Unified Soil Classification System. It should be mentioned that these materials can be used in railroad as ballast and in retaining walls as fill materials. The current study aims to investigate strength characteristics of the backfills, influenced by different parameters such as relative density of the fill materials, normal stress on the shear plane and aggregate size of the fill materials. To cover all the matters, 18 large-scale direct shear tests have been scheduled. These tests encompass two relative densities of fill materials (50% and 70% which represent medium dense and dense backfill, respectively), three aggregate sizes of fill materials (3, 6 and 12 mm- selected based on the scaling criteria on size of shear box) and three normal stresses (100, 200 and 300 kPa- these values cover rather low to high vertical stress in a soil element of common geotechnical projects) have been examined. It should be mentioned that, prior to shearing, the normal stress was applied to the specimens for a period of 1 h, in order to stabilize the soil particles from any possible creep. As all materials used in this research are of coarse-grained type and the experiments were performed under dry conditions, the displacement rate of 0.5 mm/min was selected. During the tests, the applied normal stress, displacement of the lower box, shear force mobilized at the interface and vertical displacements of the cap were continuously recorded.
Results and discussion
The curves of shear stress as a function of shear displacement and also shear displacement-vertical displacement for samples show that shear stress dropped down to a specific amount of residual shear strength after reaching maximum amount of shear stress . It was observed that increasing the particle size and relative density of the fill materials mostly fortify interlocking of the grains which in turn, resulted in increasing the tendency to expansion through the shear plane. On the other hand, the initial compression has decreased and dilation was started from a smaller shear displacement. This may be interpreted that as the soil particles size increases, more expansion is required to reach the maximum shear strength. Moreover, comparing the observed behavior, it is found out that unlike the effect of grain size and density, increasing the normal stress caused the materials to be more compressed, resulted in reducing expansion and increasing the initial compression of the soil mass. This conceivably means that increasing normal stress, transferred on shear plane, can change the failure mechanism of materials, from dilatancy failure to bulging failure under shearing. From the results, it was found out that increasing medium grains size of soil from 3 mm to 12 mm ended to improvement in the maximum friction angle at relative density 50 and 70% by the value up to 4.4 and 5.8 degree, respectively. In fact, due to increasing grain size, the grains interlocking have been fortified. In order to have a comparison, the maximum dilation angles of all fill materials, mobilized at the shear plane, have been derived. Accordingly, the maximum dilation angle was increased with the increment of the fill grains size and relative density of the material. Nevertheless, by considering variation of peak dilation angle with normal stress, it is found out that the normal stress had a negative influence on the advancement of interface’s dilation angle. These findings can be directly interpreted by considering the compression/expansion of the materials during the increment of shear displacements.
Conclusion
The current study, consists of 18 large-scale direct shear tests, aims to investigate shear characteristics of soil which influenced by different parameters such as relative density of the fill materials, normal stress at the shear plane and aggregate size of the fill materials. Eventually, the following conclusions are presented:

• Increasing relative density, soil particle size and normal stress have beneficial effect in shear strength improvement. But, the mechanisms of each parameter in this enhancement is different.
• The dilation rate of shear interfaces directly complies with changes in the ratio of applied shear stress to vertical stress. So, the maximum dilation angle and the maximum ratio  mobilized at the shear plane have occurred around the same shear displacement.
• Maximum values of friction and dilation angels have been occurred around the same shear displacement. Moreover, compaction effort leads to increase the required shear displacements to approach the maximum shear characteristics.

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Introduction
Artificial stone is a type of building material that consists of natural aggregates, binders, such as cement or polymeric resin and some additives. The aggregates used for the production of the artificial stone are generally supplied from the wastes and scraps of quarries and industrial stone manufactories. Accordingly, the produced rock has a significant economic value.
The mixing design includes more than 80% of natural aggregates and less than 20% additives and binders, such as various types of polymer resin or cement. Due to the fact that artificial stones are designed purposefully and according to engineering patterns, so the stone has different designs and colors and thus can meet the diversity of consumer desire and is an appropriate alternative for natural stones in the building industry. Due to a large number of various rock mines and industrial workshops in Iran, it has the ability to produce artificial stones.
Material and method
The purpose of this paper is to investigate the effect of silicate aggregates on the properties of artificial stones, the aggregates of the three types of natural stone tuff, andesite and granite were selected. The basis of this selection is the mineralogical variety, the textural diversity and the easy accessibility of these three stone types. The binder used in the manufacture of these artificial stones is an unsaturated polyester resin, accounted for 11% of the samples. The crushed and graded samples were poured into the mold after mixing with resin from 85% to 15% and were subjected to a compression pressure of 12 MPa for 24 hours.
Results and discussion
The summary of the results of the experiments carried out in Table 1 is presented.
Table 1. Summary of the results of the experiments on the samples

Rock type		Water absorption percentage	Point load index	Uniaxial compressive strength	Brazilian tensile strength	Weight loss (5 cycles)
Tuff	Natural	4.84	10.57	145	21.53	-0.0172
	Artificial	11.48	6.19	63	12/66	-0.0126
Change rate		▲	▼	▼	▼	▼
Andesite	Nature	1.35	10.48	84	12.83	0.0046
	Artificial	8.47	1.83	34	5.86	-0.0417
Change rate		▲	▼	▼	▼	▲
Granite	Nature	3.01	1.82	41	10.10	-0.0032
	Artificial	0.42	3.56	51	10.34	0.0083
Change rate		▼	▲	▲	▲	▼

By reviewing the results, it can be seen that the sample of artificial granite has all the desired indices of a building stone. In comparison to natural granite, the percentage of water absorption and its weight loss is lower; conversely, the point load index, uniaxial compressive strength, and tensile strength of the Brazilian are more. Electronic image observations also show more homogeneity between resin and aggregates but on the other hand, artificial tuff and andesite haven’t got favorable indices, in comparison with natural stones.
Conclusion
The conclusion of the research can be summarized as follows:
The following results were obtained by the preparation of three samples of artificial stone from three types of natural stones: Tuff, andesite and granite, and performing physical and mechanical tests and studying the mineralogical and texture characteristics of the stones:
Mineralogical studies by a polarizing microscope and XRD irradiation analysis showed that the texture of both tuff and andesite contains unstable minerals such as opal and glass materials (amorphous), alongside other minerals. On the other hand, they have a microcrystal texture that includes abundant empty spaces. In contrast, granite is mainly composed of quartz, feldspar and biotite minerals, and the stone fabric has a coherent crystalline structure.
Artificial granite has all the desired indices in comparison to natural granite. That way, the percentage of water absorption and its lost weight are reduced; on the contrary, the point load index, uniaxial compressive strength, and Brazilian tensile strength increase. While artificial tuff and andesite’s indices are not favorable in comparison to natural stone. On the other hand, their water absorption has increased, while their resistance index is lower than the natural stone. The lost weight of these two samples also shows varying conditions.
SEM electronic images taken from the artificial granite sample show good homogeneity between resin and aggregate compared to natural granite while artificial andesite and tuff specimens show the presence of empty spaces and dispersed resin materials.
Thus, it is concluded that the artificial stone samples made from granite aggregates are more suitable for mineralogical, physical and engineering properties than andesite and tuff../files/site1/files/123/2Extended_Abstract.pdf

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Aggregates are one of the high demand building materials in construction of structures and their characteristics have important effects on durability and permanence of projects. Abrasion resistance is one of the important features of aggregates that their utilization in concrete and asphalt are affected by texture and lithology of them. As rock consisted of harder minerals have higher abrasion resistance like igneous rocks, due to more siliceous minerals. More varieties in mineralogy compound usually lead to increase in aggregate abrasion. Aggregates that are contained of different minerals usually have less abrasion resistance. Porosity usually decreases the resistance abrasion. In addition to lithological properties, the environment where aggregates are deposited is important in determining resistance-related parameters of aggregates.
Rivers, alluvial fans, and taluses are the main environments where aggregates are deposited. Geological processes, such as weathering and particle movement may cause changes in natural aggregates, hence affecting their abrasion and impact resistance. Rock weathering can results in increasing porosity, producing minerals that are weaker in comparison to their original rock.
In the process of particles transport by stream water, weak parts of aggregates will be omitted. The present study is focused on the relationship between geology medium and the weight loss of aggregate in Los Angeles test. 
Methodology
Considering that lithology features in aggregates resistance against abrasion have an important role, in order to examine the effect of various geology environments in abrasion resistance of aggregates, the medium should be chosen having similar lithology. Therefore, the north of Damavand and the south of Daneh Khoshk anticline (north of Dire plain) were firstly chosen by using geology map, satellites images and field study. Damavand zone consists of trachyte and trachy-andesite volcanic rocks. These rocks cover the whole area around the Damavand peak. Also, Daneh Khoshk anticline is covered by thick Asmari formation. The selected environment are in the length of each other. Such that taluses feed alluvial fan and alluvial fans feed rivers. Samples were collected from different area of southern part of anticline. 10 river area, 12 alluvial fan and 6 taluses in the south-west area of Daneh Khoshk anticline (north of Dire plain) were chosen. Los Angeles test has been done according to standard A method ASTM D2216-10, 1990 on samples and the results were analyzed by analogous analyzer.
Results and discussion
Results show that porosity and micro-crack percentage increase, respectively in accumulated aggregate in river, alluvial fans and taluses areas. Also, porosity and micro-crack in various alluvial fans is different and is influenced by the area and length of main channel of alluvial fans’ catchment. The porosity decreases by the increase in the length of channel and area of alluvial fans’ catchment.
The percentages of aggregate weight loss in talus, alluvial fan and river areas decreases, respectively. Based on the obtained results, the lowest rates of weight loss belong to river environments (23.7 % in Daneh Khoshk and 42% in Damavand) whereas the highest rates of weight loss belong to taluses (49.3% in Daneh Khoshk and 48% in Damavand). The alluvial fans have an average state. Another noticeable point is the high weight loss in Los Angeles test in Damavand aggregate. Due to having harder mineral, igneous aggregate have more abrasion resistance, but this research illustrates that the weight loss resulting from Los Angeles test in these aggregates is high. This is because of virtues texture that weakness against the impact as well as their high porosity.
Conclusion
The result of this research indicates that the volume of aggregate weight loss in Los Angeles test is related to aggregate accumulation environment. The extent of aggregate abrasion resistance is lowest in talus medium and increases in alluvial fan and river environment, respectively. The difference in aggregate abrasion resistance in various areas result from geology process differences that applies to aggregates in various environment. The extent of caring particles in talus environment is very low and the type of movement is mass or sliding type in these media, micro-crack and weak parts remains within aggregates. The surface of micro crack is weak such that breaks easily in Los Angeles test due to the pressure results from the impact of aggregate, as well as the impact of steel ball on aggregate leading to aggregate breakages. Aggregates move more distances in alluvial fan and river. Aggregate strike together in riverbed and alluvial fan yielding to aggregates breakages from micro-cracks. As the movement distance increases, aggregates approach more to intact rock. During the particles move, the weathered and weak parts are damaged by aggregate abrasion to riverbeds and alluvial fan, and more resistant and harder aggregates remain. As the water current increases, the aggregates impact each other harder, more resistant micro-crack breakages and this change leads to decrease the weight loss in Los Angeles test.
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Introduction
Urban development and rapid extension of cities have been accompanied by a considerable growth in mechanized tunneling. The abrasivity of rock and even soil is a factor with considerable influence on the wear of tools. Soil abrasion and the resulting tool wear has a major impact on machine operation, utilization, and tunneling costs and time. One of the problematic aspects of working in abrasive grounds is the frequent need for the replacement of cutting tools, especially in pressurized face tunnel boring machines (TBMs). The effect of worn and damaged TBM cutter heads has been documented for numerous tunnel projects around the world. However, the lack of a standard or universally accepted test for soil abrasivity in geotechnical investigations has made the prediction of tool wear a difficult task.
Material and methods
A reliable prognosis of the abrasiveness of soils on a project would be of great benefit for designers, clients, and contractors. Many abrasion tests exist for rocks, and some have been proposed for soils; however, there is no universally accepted or international standard test for soil abrasivity testing. One of the most important and available tests in this field is LCPC abrasivity test which was developed by the Laboratoire Central des Ponts et Chaussées in the 1980’s. The LCPC Abrasivity Coefficient (ABR or LAC) can be used as a measure for both the abrasivity of the soil material and the influence of the grain size. The  abrasivity  testing  of  rock  is  controlled  by well-known parameters, whereas in soils many factors are influencing the abrasivity such as in-situ soil conditions, sedimentary petrology and technical   properties.
Tabriz metro line 2 Project about 22 km in length that will connect eastern part of the Tabriz city to its western part, considered as a case study. The project comprises a single tunnel which has been constructed using two earth pressure balance EPB-TBM with a cutting-wheel diameter of 9.49 m. In this study, based on geological and geotechnical properties, the tunnel route was divided into four parts and the abrasion and brittleness coefficients of alluviums determined by LCPC test. Besides that, the influences of some factors such as moisture content, mineralogy, grain size and shape, type and amount of foam have been studied.
Results and discussion
Based on more than 130 LCPC test results, in general, the Tabriz Metro’s line-2 route alluviums have the abrasion in the range of low to very high and the brittleness in the range of high to very high. In order to measure the effect of moisture content on abrasion and brittleness coefficient, the LCPC test was done on some samples related to the tunnel route in dried and moistened modes (5%, 0%, 15%, 20%, 25%, and 30%). Three types of sandstone, andesite, and conglomerate of the route were used to test the effect of moisture and petrology on abrasion. In a moisture range of 0 to 5%, in all types of materials, abrasion was increased. In a moisture range of 5 to 10%, abrasion was decreased in all three types, and this shows that a moisture level of 10% is a normal moisture content to create minimum abrasion. The behavior of sandstone and conglomerate is similar at higher moisture contents, and an increase in moisture content to 30% can increase abrasion of materials in both types. In conglomerate, abrasion at higher moisture levels is significantly more than in other modes. In andesite, an increase in moisture content to 20% can increase abrasion, although the abrasion is decreased with a moisture content of over 20%. In most samples, increase in moisture content led to decrease in brittleness of materials. In general, the highest abrasion level was related to conglomerate and the lowest level was related to sandstone. Moreover, andesite was at a lower level than conglomerate and a higher level than sandstone in terms of abrasion. Also, the results show that increased grain size led to increased abrasion, and the changes in andesite were greater than in sandstone.
In order to test the effectiveness of foam on abrasion, the foam used in workshops (A 168) made by Komeil Company Kashan was used for four types of petrography: conglomerate, andesite, sandstone, and silica. This test was conducted in the range of dried to 100 ml foam. In all types, decreased abrasion is observed from 0 to 20 ml and increased abrasion is observed from 20 to 100 ml.
Conclusion
The following conclusions are drawn from this research.
- With regard to the effect of grain size, increased size of grains could lead to more abrasion and less brittleness
- In terms of the effect of mineralogy, the conglomerate had the most effect on abrasion. In terms of brittleness, andesite was the most brittle.
- When the foam is moisturized in the sample, minimum abrasion is observed and above this level, the abrasion is increased.
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Abstract
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.
Introduction
Given the variation of construction materials, the importance of the economy in its supply and large use of natural stone mines and the production of seemingly unusable slags, it is necessary to reuse these slags. One of these reusing methods is to make artificial stones and its application as construction materials. Rock powder, aggregate, a small amount of cement or resin and other chemicals are used for producing artificial stone. In this study, carbonate minerals, rock powder and white cement in the first phase are mixed and wet. Then, in the next stage, to form the sample in a cubic mold, they have been compacted under three physical processes of vibration, vacuum and pressure. The aim of this study is to investigate how to make artificial stone, to evaluate the engineering properties of artificial rock and the effect of limestone engineering properties on artificial stone properties of non -resin cement and then comparing the properties of artificial rocks made with natural stones
Material and methods
In this study, in order to investigate the effect of calcic aggregates properties on artificial stone properties, seven samples of building carbonate rocks including crystalline marble, two samples of marble, black limestone, and two samples of travertine and onix were used.
Engineering geological properties of the used samples were then determined. In the next stage, after designing mold 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. After construction, physical, strength and durability tests were conducted, and then the results were compared.
Results and discussion
Investigation of the effect of engineering geological properties of carbonate aggregate on artificial stone properties showed that the artificial stones made of travertine aggregates have higher quality than natural travertine in terms of physical, strength and durability properties. Due to the existence of pores on the surface of travertine aggregates, the used cement can result in reducing effective porosity and increasing strength and durability in the artificial stones.
In Table 1 a proposed research has been used for rating rock engineering parameters based on the degree of importance for building stones. Then, according to this table, the score of each natural stone and related artificial stones were determined. For building stones, the importance of durability and strength is more than the density.  Also, the density shows its effect on durability. At the same time, with increasing the percentage of water absorption, the durability of rock has decreased. Therefore, the rocks with less water absorption are more important.
Table 1. Scoring of building stones based on the engineering parameters

Parameters	Description	Excellent	Good	Marginal	Poor
	Total score	100	75	50	25
Water absorption (%)	Range	0-2	2-3	3-5	>5
	Score	25	20	15	10
Unit weight (kN/m3)	Range	>24	22-24	18-22	<18
	Score	15	10	5	3
Uniaxial compressive strength (MPa)	Range	>50	40-50	30-40	<30
	Score	20	15	10	4
Tensile strength (MPa)	Range	>20	15-20	10-15	<10
	Score	20	15	10	4
Durability (%)	Range	<1%	1%-2%	2%-3%	>3%
	Score	20	15	10	4

The total score of fine-grained artificial stones (65%) is almost similar, indicating that the type of carbonate grains does not affect the characteristics of fine-grained artificial stones, but the total score of coarse artificial grains are in the range of 58 to 74%. This range of score indicates that structural weakness, especially the cleavage surface, porosity, lamination, vein and acetylolite of aggregates have more influence on engineering properties in coarse-grained artificial rock.
Conclusion
Comparison between the engineering properties of artificial and natural stones were studied. The following conclusions were drawn:
- The artificial stones of Hojjatabad travertine have similar engineering quality with their natural stone.
- Both 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 6 to 33% decrease in quality compared to natural stone but in acceptable ranges when they are considered as construction materials.
- The samples made of other rock samples have lower quality than natural stones; however, they are placed in the acceptable range as building materials../files/site1/files/144/Mirjalili.pdf