Validity of Euphrates River Terraces Deposits between Baghdad and Fallujah for Concrete Works

Abstract


Introduction
Concrete is a structure composed of several materials and the largest part is aggregate coarse and fine which occupies about 70-75% of the total volume of the concrete mass (Neville and Brooks, 2010), thus, it is the main component of the concrete body and therefore, the properties of the aggregate will be reflected on the properties of the concrete produced (Alexander and Mindss, 2010).Aggregate is a relatively cheap material compared to cement, so it gives a good economic cost to concrete, in general, the greater amount of aggregate present in a certain volume of concrete, the more economical the resulting concrete.Moreover, the aggregate gives concrete its stability and resistance to the forces and external loads it is exposed to, ground factors and the action of various weather factors such as heat, humidity, freezing and concrete bearing with time, in addition to working to reduce volume changes as a result of contraction and expansion in the concrete mixture resulting from changes in external factors.The role of aggregate as a filler has an effect on the most important property of concrete, which is the compressive strength, as the concrete's resistance to compression depends on the strength of the aggregate.Therefore, the aggregate materials must be selected with high accuracy.In order to achieve the required results in work, the engineering, mechanical and chemical properties of these materials must be known and their conformity with the standard specifications.The site research is located between Baghdad and Anbar governorate along the highway road linked between Abu-ghraib and Falluja, and at a length of about 20 km, the study area is located between 43  46'0" -44  0'0" longitude and 33  16'40"N -33  23'40"N latitude (Fig. 1).There are few previous studies related to the topic of the research.Al-Maadidi, 2015, studied the geotechnical assessment of aggregate in Chiman and Shurau areas northeast Kirkuk City for roads and concrete uses.He concluded that the aggregate conforms to the standard specifications which suitable for concrete works.Fathi (2019) has studied the ability to using the natural aggregates of quaternary deposits for the Lower Zab River Terraces at Alton Cobri -Kirkuk Governorate, Concrete Works.He concluded that the possibility of using aggregates in concrete works after the washing process, in order to comply with Iraqi and international standards.Al-Tamimi, 2020, studied the validity of the comprehensive aggregate for some construction uses in selected areas of Kirkuk Governorate -northern Iraq and concluded that the results do not match the Iraqi standards for concrete works.The current research aims to study the geotechnical properties of the available aggregate deposits in the study area and compare the results with the American Standard Specifications ASTMC33-03 and British Standard Specification for Building Materials, to determine their suitability for concrete works and to take advantage of these deposits available for the completion of engineering projects.

Geology of the Study Area
The sediments excavated in the study area are Quaternary deposits Pleistocene (Yacoub et al, 1991), which consist of friable sediments from sandy gravel, with sandy lenses that covered Injana Formation Upper Miocene.These sediments have high economic value as a source material of sand and gravel which uses in many civilian and engineering buildings even in road base bed (Saleem, 1978) (Fig. 1).
The average Gravel grain size is ranged between 2-5cm, which decreasing foreword of the flood plain characterized as rounded to sub-rounded and sub-angular consisting of quartz, limestone, chert and some of igneous and metamorphic fragments.(Deikran and Yacoub, 1993).The geology of the study area is shown in Fig. 2. For more details on the geology of the study are see Deikran and Yacoub (1993).

Materials and Methods
Samples were collected from sedimentation detectors in the study area according to the American Standard Specifications for sampling ASTM-D75, 2004, with 4 samples from different locations.Table 1 shows the coordinates of the sample's locations.The aggregate was separated into fine and coarse parts using sieve No. 4 the size of its slots 4.75 mm; then the samples were used to conduct laboratory tests according to standard test methods to determine the aggregate's required physical, mechanical and chemical properties.All the results were tested in compliance with the American Standard Specifications ASTMC33-03 for the aggregate used in concrete to ensure the quality of concrete produced.

Physical Tests
Physical tests were performed in the laboratories of the Department of Geology at Tikrit University.

Sieve analysis
The concept of granular gradation is of great importance in concrete works, as good granular gradation reduces many engineering problems during the design of the concrete mixture and has a key role in increasing the durability, structure and behavior of the produced concrete, as it affects the efficiency of the bonding between the aggregate and the cement material (Zongjin, Li, 2011).This leads to reducing the porosity by reducing the gaps and voids in the concrete (Suchorski et al, 2007).Table2 shows the limit of the standard specification ASTM C33-03 for fine aggregates whereas.Table 3 shows the limit of the standard specification ASTM C33-03 for coarse aggregates.Figs. 3 and 4 show the results of the sieve analysis of fine and coarse aggregates, respectively.

Fineness modulus
The fineness coefficient is defined as the factor that describes the average size of the aggregate and is deduced from the sieve analysis table of the aggregate by adding the cumulative percentage reserved on the standard sieves divided by 100.(Zongjin, 2011) provided that the standard sieves are arranged from the smallest size at the bottom to the largest Size is found in the aggregate sieve analysis as table above.The American Standard ASTM C 33-03 specified that the limits of the fineness modulus range between 2.3-3.1 for fine aggregate used in concrete and the results were within the permissible limit according to the standard.

Specific gravity& absorption ratio
Specific weight is the ratio of the mass of a unit volume of a substance at a given temperature to the mass of the same volume of gas-free distilled water at the same temperature and it is a value that has no units (Khalaf and Issa, 2021).In the current study, the total specific weight and the apparent specific weight were calculated.
The apparent specific weight is the ratio between the mass of a unit volume in the air of the impermeable solid aggregate granules at a given temperature to the mass of the same volume of gasfree distilled water in the same air and temperature.The apparent specific weight is related to the relative density of the solids taking into account the basic grains and does not include the spaces between the grains.It is expressed as the apparent relative density .
The total specific weight is the ratio between the mass of a unit volume in the air of permeable solid aggregate particles (including the permeable and impermeable gaps in the material) at a given temperature to the mass of the same volume of gas-free distilled water in the same air and at the same temperature.(Alexander and Mindss, 2010).It is the characteristic generally used in calculating the volume occupied by the aggregate in many mixtures containing aggregates, including Portland cement concrete, bituminous concrete and other mixtures.The total specific weight is also used in calculating the spaces between the aggregate grains.It is expressed as the total relative density.ASTM C127,2004 As for the absorption ratio, it is defined as the increase in the total weight of the aggregate as a result of water entering the pores of the solid material of the aggregate granules (Alexander and Mindss, 2010), and does not include water adhered to the outer surface of the granules .
It is an indirect method for measuring permeability in aggregates.It is also an indirect method for measuring the resistance of aggregates to physical weathering processes, as aggregates with low absorbability are more resistant to weathering processes, in other words, they are resistant to the effect of weathering (Smith and Collis, 2001) The specific weight of the coarse aggregate was tested according to the American Standard Specifications ASTM C127, 2004, the results of the test for all sites are shown in Table 4.As for the fine aggregate, the specific weight and absorption ratio of the samples were checked according to the American Standard Specifications ASTM C128, 2004, the results of the test for all sites are shown in Table 4.

Grain shape
The presence of flat and elongated shapes affects the increase in the ratio of gaps and voids, thus needing a greater amount of water and cement to cover the entire external surface and negatively affecting the workability and reducing the resistance of concrete (Rao, 2004).The shape of aggregate granules has been divided into six main shapes, round, irregular, lamellar, angular, elongated, lamellar, and elongated granules British Standard BS 812:1990 (Smith andCollic, 2001).The presence of elongated aggregate granules in the concrete mixture leads to the trapping of water under these granules and thus requires an increase in the mixing water, which affects the workability of the concrete (Alexander and Mindss, 2010).

Flakiness index
The flatness coefficient of large aggregates is defined as the percentage of aggregates whose grain thickness is less than 0.6 from their average nominal size to the total aggregate sample weight (Smith and Collic, 2001).Based on British Standard BS 812-105.1:1990, and then compare the results with the limit index of the British Index BS 882: 1992 that show the Flakiness Index should be no more than 50% and the test results were conform to the limits of the standard.

Elongation index
The elongation coefficient is defined as the percentage of aggregates whose grain length is more than 1.8 unit from their average nominal size to the weight of the aggregate sample (Smith & Collic, 2001).The test was carried out based on British Standard Specification BS 812-105.2:1990, and then the results compare with the limit index of the British Index BS 882: 1992 which show the Elongation Index should be no more than 50% and the test results were conform to the limits of the standard.

Deleterious materials in aggregates
They are materials whose presence may negatively affect the workability, strength and performance of concrete in the long term.These materials are considered undesirable because of their weakness, softness, softness to the touch, or other physical or chemical properties that are harmful to the behavior of concrete (Gambhir, 2013).It can be divided into three main categories • Impurities interfere with the cement hydration process • Insulators that prevent the formation of a good bond between the aggregate and the cement paste .
• Weak particles or a chemical reaction occurs between them and the osmotic paste .

Materials passing through sieve No. 200 with holes size 75 micrometers by washing method
This method is used for the purpose of accurate determination of the percentage of fine materials passing through sieve No. 200 that adhere to large particles of coarse or fine aggregates.This test is used for the model before the granular gradient is tested and sieved by the dry method.The test was carried out according to the American Standard Specifications ASTM C117/2004.According to the American Standard Specification ASTM C33-03 the percentage of the fine materials should not increase more than 1% in coarse aggregates and no more than 5% in fine aggregates, the test results of fine aggregate were conformed to the limits of the standard and as for the test results for coarse aggregates they conform to the limits of the standard in sites 1 and 3, but the test results in the sites 2 and 4 not conform to the limits of the standard.

Clay Lumps and friable particles test
This test is performed on the remaining sample after completing the test of the materials passing through sieve No. 200 with a capacity of 75 micrometers.The test was carried out according to the American Standard Specifications ASTM C142/2004.
According to the American Specification Standard ASTM C33-03 the percentage of the lamps and Friable Particles should be no more than 3% in fine aggregates and no more than 5% in coarse aggregates, the test results of coarse aggregates were conformed to the limits of the standard and as for the test results for fine aggregates they conform to the limits of the standard in site 4 but the test results in the sites 1, 2and 3 not conform to the limits of the standard.

Lightweight particles
This assay is used to determine the amount of light weight material in fine and coarse aggregates.Where dense liquids are used to separate the light weight particles that are classified as coal, lignite, flint or shale, and this test is also used to identify porous aggregate particles.In this study, a solution of zinc chloride with a specific weight of approximately 2 was used.The test was carried out according to the American Standard Specifications ASTM C123-04, According to the ASTM C33 -03, it should be the lightweight particles no more than 0.5% in fine and coarse aggregates, the results of the test showed that all sites conform to the limits of the standard.

Mechanical Tests
Mechanical tests are necessary for evaluating the aggregate resistance of aggregates during the production and transportation of concrete mixtures, as aggregates are likely to be exposed to harsh conditions in these processes.Weak aggregates may disintegrate during mixing, mixing and transportation, which leads to a loss of workability (Alexander and Mindss, 2010).The presence of aggregates in exposed concrete is subjected to several forms of corrosion such as friction, grinding, scratching, shocks and mechanical wear (Alexander, 1985).Mechanical testing was conducted in the laboratories of Tikrit University's Department of Geology.

Aggregate crushing value test
It is defined as building aggregates for crushing under the influence of gradual pressure.The test was carried out according to the British Standard BS 812-110:1990, which gives that the Aggregate Crushing Value for the coarse aggregates should be no more than 30%, the test results were conform to the limits of the standard.

Aggregate impact value test
This test means that the ability of coarse aggregate to resist collapse as a result of exposure to impact loads.The test was carried out according to the British Standards BS 812-112:1990, which determined the value of the impact resistance of coarse aggregate should not be more than 45% for aggregate used in ordinary concrete and 30% for aggregate used for concrete roads and sidewalks and the test results were conform to the limits of the standard.

Los Angeles abrasion test
It describes the aggregates' resistance to corrosion caused by abrasion and friction.The hardness quality of aggregates used in concrete is crucial, particularly for concrete used in floors and surfaces exposed to heavy traffic, such as roads.The assessment test was conducted in accordance with American Standard ASTM C131-01, 2004, which established that the value of abrasion for coarse aggregate should not be greater than 50% of the aggregate used in all forms of concrete.The results of the test showed that all sites conform to the limits of the standard.

Soundness of aggregate
This term expresses the ability of the aggregate to resist successive volume changes resulting from changing the natural conditions weathering and erosion conditions (Smith and Collic, 2001), such as exposure to cycles of cold, ice and melting or moisture and dryness, and these volume changes cause damage to concrete (Neville and Brooks, 2010) .
The stability test was carried out by chemical method according to the American Standard ASTM C88-05 for five consecutive cycles using sodium sulfate solution.According to the ASTM C33-03 the loss percentage in weight by using sodium sulphate should no more than 10% for fine aggregates and no more than 12% for coarse aggregates.The results of the soundness test for the search area models are shown in Table 4, and it was within the permissible limit for coarse and fine aggregates according to the standard.

Chemical Analysis
Chemical analyzes were performed in the laboratories of the Chemical Engineering Department at Tikrit University.

Chloride content
The chloride salts are characterized by their ability to dissolve in water and the presence of chloride salts with sulfate salts in the same media leads to an increase in the solubility of sulfate salts (Van Anrdt, 1962).The presence of chlorides, whatever their source, in concrete destroys the surface protection layer of iron and stimulates the formation of rust.The content of chlorides in coarse aggregates and fine aggregates used in concrete works was determined according to test No.3 of the British Standard Specifications BS 1337-2018 and then compare the results with the limit of the British standard BS 882 : 1992 that show the chloride content of aggregates should be no more than 0.05% and the test results of coarse aggregate were conform to the limits of the standard but the test results of fine aggregate not conform to the limits of the standard.

Sulphate content
Sulfates are salts with a negative ionic charge that have the ability to dissolve in water, interacting with concrete and causing deterioration and weakness of concrete (Kheder, 2009).The sulfate content of aggregates used in concrete works is determined by test No.5 of the British Standard BS 1337-2018 and then compare the results with the limit of the British standard BS 882: 1992 that show the sulfate content of aggregates should be no more than 1% in the coarse aggregate and 0.5-1% in the fine aggregate, the test results showed that the sulfate content is within the permissible limit according to the British Standard.

Organic matter content
These materials generally consist of decaying plant materials, which appear in the form of humus.The impurities in the form of organic matter enter into chemical reactions with the mixing water, affecting the proportion of the mixing water and the shrinkage that occurs as a result of dissolving organic materials negatively affects the durability and strength of concrete (Gambhir, 2013).The examination was carried out according to the British Standard BS 1337-2018, which is based on the colorimetric test to indicate the content of organic matter in the aggregate should not be more than 0.5% in coarse and fine aggregates and the results were within the permissible limit according to the standard.

Total soluble salt
It is considered one of the harmful substances present in the aggregate and it is the percentage of the total salts that have the ability to dissolve in water to the weight of the aggregate.The test was carried out according to the American Standard ASTM Earth Manual, E8 which established that the percentage of the total salts for aggregates should not be more than 10%, the test results of the sites 1,2 and 4 were conform to the limits of the standard but the test result of the site 3 not conform to the limits of the standard.

Results and Discussion
The sieve analysis results of fine and coarse aggregates for the four sites in the study area are shown in Figs. 3 and 4 respectively.Table 4 shows the results of physical and mechanical tests for fine and coarse aggregates used in concrete and Table 5 shows the results of chemical tests for fine aggregates and coarse aggregates used in concrete .
The results of the sieve analysis of fine aggregate showed a deviation in the gradient values when matching the results with the limits of the American Standard Specification for Building Materials ASTM C33-03.In the first site, there is a deviation at the granular size 300m and 2.36mm, while in the second site there is a deviation at the particle size 2.36 mm, but the third site there is a deviation at the particle size 300m only, and in the fourth site there is a deviation at the particle size 2.36 mm.As for the results of the sieve analysis of the coarse aggregate, it appeared that the results for the four sites matched with the nominal size 4.75-19mm when compared with the limits of the American Standard Specification for Building Materials ASTM C33-03, with a deviation at the particle size 19mm in the second and third sites when compared with the nominal size 4.75-19mm.The results of the smoothness coefficient showed a conformity with the limits of the American Standard for Building Materials ASTM C33-03 for all sites.The results of the test showed that the values of the dry specific weight of the coarse aggregate amounted to 2.59, 2.55, 2.56 and 2.59 respectively, and that the values of the saturated specific weight amounted to 2.61, 2.58, 2.59 and 2.61 respectively, while the apparent specific weight values amounted to 2.64, 2.63, 2.64 and 2.64 respectively, and the absorption ratio of coarse aggregate was 0.82, 1.26, 1.07 and 0.60, respectively.
As for the fine aggregate, the dry specific weight values were 2.63, 2.62, 2.62 and 2.63, respectively, and the saturated specific weight values were 2.67, 2.66, 2.65 and 2.67 respectively, while the apparent specific weight values were 2.75, 2.72, 2.72 and 2.73 respectively, and the absorption rate of fine aggregate was 1.63, 1.42, 1.44 and 1.40 respectively.The results of testing the passing fine materials from sieve No. 200 for coarse and fine aggregates show that the first and third sites conform to the American Standard Specifications for Building Materials ASTM C33-03, while the second and fourth sites do not conform to the mentioned standard specifications.The results of the test of clay blocks and friable materials for fine aggregates show that the first, second, and third sites do not conform to the standard specifications and match the fourth site only.As for the coarse aggregate, the results of all sites conform to the standard specifications.The results of the examination of light weight materials for fine aggregates and coarse aggregates are shown.The results of the test for all sites conform to the limits of the standard.The test results of the elongation coefficient and the flatness coefficient show that the test results for all sites conform to the limits of the British Standard BS 882: 1992.The results of the size stability test for fine and coarse aggregates chemical erosion using sodium sulfate for five consecutive cycles show that the test results conform to the limits of the standard.As for the mechanical tests, which include the value of the crushing factor, the value of the shock factor and the resistance against wear using the Los Angeles device, the results of the test showed that all sites conform to the limits of the standard.As for the chemical analyzes, the percentage of chlorides in coarse aggregate was 0.005, 0.007, 0.006 and 0.004% respectively, while the percentage of chlorides in fine aggregate was 0.12, 0.18, 0.17 and 0.16% respectively, the test results for coarse aggregate within the acceptable range, but those for fine aggregate did not within the acceptable range.The sulfate percentage in coarse aggregate was 0.044, 0.072, 0.038 and respectively, while the sulfate percentage in fine aggregate was 0.58, 0.96, 0.57 and 0.16% respectively, the test results for coarse and fine aggregates within the acceptable range, the percentage of gypsum was 1.24, 6.03, 1.22 and 0.52% respectively, and these percentages within the acceptable range.The percentage of organic matter was 0.089, 0.035, 0.097 and 0.034% respectively, and the test results for all sites within the acceptable range for the limits of the standard.The percentage of total soluble salts was 2.75, 9.61, 15.07 and 1.21% respectively, and the test results of the sites 1,2 and 4 within the acceptable range but the test result of the site 3 not conform to the limits of the standard.

Conclusions
The Fine aggregates of the river terraces of the Euphrates River locate between Baghdad and Fallujah can be used in concrete works which is comply with the gradient limits of the American standard specifications except for the granular size 2.36 mm, where this size appears less than the permissible limits and this indicates the roughness of the aggregate, and there is an increase in Granular size 300m, which is due to the frequent washing of sediment due to its proximity to the Euphrates River.As for the coarse aggregate, it matches the nominal size 4.75-19 mm except for the granular size 19 mm, which appears to be less than the permissible limit.This indicates that the coarse aggregate contains more coarse quantities than the specified quantities.Therefore, differences in the particle sizes of fine and coarse aggregates must be taken into consideration when determining the mixing ratios of coarse aggregate and fine aggregate.Washing the fine and coarse aggregates well before use in concrete works should be taken into account to get rid of impurities, harmful substances and salts.

Fig. 3 .
Fig.3.Gradation of fine aggregates of the study area: (a) Gradation of fine aggregates for the first site; (b) Gradation of fine aggregates for the second site; (c) Gradation of fine aggregates for the third site.(d) Gradation of fine aggregates for the fourth site.

Fig. 4 .
Fig.4.Gradation of coarse aggregates of the study.(a) Gradation of coarse aggregates for the first site (b) Gradation of coarse aggregates for the second site (c) Gradation of coarse aggregates for the third site (d) Gradation of coarse aggregates for the fourth site.

Table 1 .
The coordinates of the sample's locations

Table 2 .
Grading requirements for fine aggregate

Table 4 .
The test results fot the coarese and fine aggregateusing in concrete

Table 5 .
Chemical analysis results