bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of factors influencing the compressive strength of Portland cement statistically
Authors: Salih M A , Aldikheeli M R , Shaalan k A 
Published: March 2020

Abstract
One of the most effective parameters that influence the performance of concrete is the compressive strength of cement. The chemical composition and the physical properties of Portland cement (PC) can be greatly affected the compressive strength of it. So the aim of this study is to make a statistical analysis for the effect of many factors on (3, 7, 28, and 60 day) compressive strength test results. The factors investigated include the main four compounds of cement (C2S, C3S, C3A and C4AF) in addition to (CaO, MgO, SO3, loss on ignition (LOI), insoluble residue (IR) lime saturation factor (LSF), silica modulus (SM) and alumina ratio (AR)). Furthermore fineness, unsoundness and setting time of cement were also studied. To attain the aim of the present work a statistical program “Statistica” was used for the analysis. It was found that (C3S, C3A and C4AF) compounds has a good correlation with compressive strength, while (C2S, CaO, MgO and SO3) has a negative effect especially at age of 3 days, considering that (C2S and SO3) effect became positive at 7 day age onward. The effect of (LSF and fineness) was positive on compressive strength and the effect of (LOI, IR, SM, AR, unsoundness, fineness, IST, FST) was negative.
Impact resistance and mechanical properties of High Strength Concrete containing local material
Authors: Shabbar Rana 
Published: March 2020

Abstract
High Strength Concrete (HSC) is an expression which is used to define a concrete with high performance and strength exceeds 40 MPa. The high elasticity or strength and low shrinkage and permeability are considered the main properties of the HSC. The aim of this study is to investigate the effect of High Reactivity Metakaolin (HRM) and/or Silica Fume (SF) on the properties of HSC. Local material “Kaolin Clay” was prepared as a pozzolana and the final product confirms the physical and chemical requirements of natural pozzolana. Eight mixes of the HSC with partial cement were replaced by HRM and SF (either individually or in combination). The effect of HRM and SF on the compressive, flexural strength, splitting tensile, impact resistance and modulus of elasticity of the HSC were studied. The results showed that the mix with 10% of HRM provided higher effect on the mechanical properties and impact resistance of the HSC. In addition, the HSC with the combined of 5% SF and 5% HRM
exhibited greater performance and more economic than other mixes.
Flexural Behavior of Square Ferrocement Panels Enhanced with Recycled Tires Sim Strengthened by CFRP
Authors: Jomaah Muyasser M. , Ismael Zeyad T. , Majeed Marwah Q. , Hameed Banan M 
Published: March 2020

Abstract
This paper presents an experimental algorithm with the results of using steel fibers in ferrocement panels, which were recovered from tires scrap. Waste steel fibers were cut with the same geometrical characteristics of normal steel fibers and were used in the panels at different layers. To have a reference ferrocement specimen, a plain mixture without fibers and mixtures containing a ratio of recycled steel fiber were also prepared. Some mechanical tests, such as compressive strength, splitting tensile strength and flexural strength were determined. Furthermore, load deflection behaviors for 24 panels specimens were carried out under patch load. Test results show that the recycled steel fibers layers recovered from scrap tires affected the mechanical behavior of ferrrocement panels that are similar to the number of wire mesh layers. Depending on the distribution of R.S.F layers and wire mesh layers, the load-deflection curves were found. A comparison between these curves indicates that the R.S.F can reduce the deflection of panels, and increasing the number of wire mesh layers can increase the ability to bear stresses for panels. Rehabilitation with carbon fiber strips CFRP carried out with three forms (box network, inclined with diagonal, parallel to the diagonal and mix of diagonal and box network). The curves show that the rehabilitation with a parallel form to the diameter of the sample is a better treatment, which is characterized by resistance to stresses rather than other forms. We estimate that the recycled steel fibers increase the flexural strength and tensile strength, and 10% is the optimal ratio for increasing the flexural strength and tensile, increasing the number of wire mesh layers increases the ability to bear stresses of the panels. Recycled steel fibers can cause reduction in the deflection of ferrocement panels and can give the same bearing strength proximity (or less) to the panel containing the same number of wire mesh layers.
Some properties of sustainable concrete with mixed plastic waste aggregate
Authors: Khalil W I , Mahdi H M 
Published: March 2020

Abstract
The objective of this research is to study the influence of using waste material (irregular plastic mix) on and properties and behavior of concrete. Various coarse plastic aggregate of 15, 25 and 45 % as replacement to coarse natural aggregate by volume were carried out. The experimental program consists of many tests, compressive strength, splitting tensile strength, flexural strength, thermal conductivity, absorption of water and density. The results demonstrate that the increase of plastic waste content decreases the compressive strength; while the workability slightly improves. The dry density of the concrete decreases with the increase of the plastic waste aggregate, satisfied structural lightweight concrete can be produced with 45% replacement of plastic waste aggregate. Also, a major improvement in the thermal conductivity was observed, while the absorption of water growths as the plastic waste content increased.
Strength and thermal conductivity of geopolymer pervious concrete made from artificial lightweight aggregate
Authors: Nasser I F , Khalil W I , Abbas WA 
Published: March 2020

Abstract
In this paper, geopolymer lightweight aggregate pervious concrete (GPLWAPC) was studied. It utilized two ratios of blending, which are 1:4 and 1:5 (fly ash: local artificial coarse aggregate). The rough aggregates utilized were graded as well as made of single size. An optimal ratio of aggregates content was achieved via the technique of trial and error. The fly ash (FA) that was used was low calcium, while the alkali activating element represents sodium hydroxide (NaOH) along with sodium silicate (Na2SiO3) with proportion of 1:2.5. Mixture was made with alkaline liquid to fly ash 0.4 proportion, NaOH concentration of 16 molarity was used. The artificial graded coarse aggregate to fly ash proportion of 1:4 shows the highest compressive strength with 5.2 MPa at 7 days with density of 1340 kg/m3. Many experimental investigations on GPLWAPC were investigated; workability and the strengths of compressive and splitting tensile, at the age of 7, 28 and 56 day, were studied. Moreover, thermal conductivity and scanning electronic microscopy were examined at 28 day age for the same mixture.
Study the effect of using different quenching mediums on erosive wear behavior of high chromium white cast iron
Authors: Betti Zainab Azeez , Ataiwi A. H. 
Published: March 2020

Abstract
In order to a accomplish economically good martempering process, it is required to find a cheaper and more available alternative quenching medium for the ordinary nitrate mixture used in this process. A high chromium white cast iron, which is generally used as mill liners in mining, crushing, and cement plants, is subjected to severe conditions of wear/impact. These conditions lead to failure and reduction in part life as well as increase in the cost of repairs, therefore, it is important to enhance its mechanical properties. The effect of different quenching mediums used in martempering treatment on the erosive wear, microstructure and mechanical properties of this cast iron was studied. In this study, two types of quenching mediums were used: Nitrite mixture (50% NaNO3 + 50 % KNO3) and Hydroxide mixture (50% NaOH : 50% KOH). The specimens were austenetized at 950°C for 1 hr then the first group was quenched in nitrate mixture and the other was quenched in hydroxide mixture, both at about 350°C, for (1/2, 2, 4, 6, 8) hrs. It was concluded that the two mediums enhance erosive wear resistance, but the nitrate mixture show the best erosive wear results among the other treatments, especially at martempering about 350°C for 4 hrs.
Mechanical and durability properties of cementitious brick containing Nano Ferrite
Authors: Rawdhan Rasha R. , Salman Ghaed K. , Ismail Muaid M. 
Published: March 2020

Abstract
This research investigates the influence of addition of Nano materials (Nano ferrite) on the physical and mechanical properties of the cementitious brick, by adding 1, 2, 3% of Nano ferrite by weight of cement. Bearing strength tests at RT and exposure to 100, 200, 300°C temperature after 4 hour, Bulk density and water absorption of resulting bricks were tested. Ni-Zn-Mg-ferrite nanoparticles were prepared using citrate auto combustion method using the X-Ray Diffraction (XRD) to characterize the prepared sample where found the particle size is (49.6 nm) with good crystalline structure. The results show that possibility to synthesize nanoparticles, the optimum content of the Nano ferrite was 2% that produces the ultimate increase in the bearing strength and improvement in physical properties. The mechanical test results showed a tendency to lose strength at high temperature. It was found that a decrease in the water absorption from 4.913 to 3.273 wt % occurred at 3% of Nano ferrite.
Improvement of polyurethane thermal insulation materials by using corn stalk
Authors: Karapinar I Sanri 
Published: March 2020

Abstract
The heat loss during the heating of buildings constitutes about 40% of the greenhouse gas emission that causes global warming. Thus, in order to decrease the energy for heating buildings, various kinds of insulation systems and materials have been used. In this study, by using corn stalks, a polyurethane insulation material was produced. The unit weight, ultrasonic pulse velocity and thermal conductivity coefficients of the produced material were determined. The thermal conductivity coefficient of this composite material was found to be 0.042. The insulation values obtained were in an acceptable range, i.e. they satisfy the Turkish Standard TS 805 EN 60155. Thus, with the zero-waste objective, this study presents an alternative construction material containing a certain type of waste material, also avoiding the environmental problems it causes.
Field study of the effect of jet grouting parameters on strength based on tensile and unconfined compressive strength
Authors: AL-Kinani Ali M , Ahmed Mahmood D 
Published: March 2020

Abstract
The improvement of the mechanical soil characteristics of jet grouting technique is very attractive. The jet grouted soil cement columns in soft is a complicated issue because it depends on a number of factors such as, soil nature, mixture, influence among soil and grouting materials, jetting force of nozzle, jet grouting and water flow rate, rotation and lifting speed. This paper discusses the estimation of shear strength parameters of soil-cement column (soilcrete) in soft clayey soil based on the relationships between the unconfined compressive and split tensile strength for the soilcrete and the effect of the jet grouting and water pressure in the values of cohesion and internal friction. For this reason, theoretical and field work models have been developed. The relation between split tensile and unconfined compressive strength results were used to draw a Mohr’s circle and failure enveloped to define the shear strength parameters of soilcrete. According to that, the results indicate that the resistance of the jet grout columns increases by increasing the nominal resistance of the grouting material (cement), water and jet grouting pressure. The shear resistance variables are increased by increasing the unconfined compressive and tensile strength of the jetting column. The value of the unconfined compressive strength ranges from (2.78-5.52 MPa). While the internal friction angle varies from 38° to 44°. On the other hand, the tensile strength is increased by increasing the unconfined compressive strength and ranges from (0.66-1.02 MPa).
Numerical evaluation of rock strength with different sizes of circular opening
Authors: Al-Obaydi Moataz A , Al-Jobory Yussra H 
Published: March 2020

Abstract
The presence of opening in the rock may be natural or artificial. In such circumstances, the stability should be examined through studying the strength of the rock. In the present study, the effect of size of the circular opening on the compressive and flexural strengths of limestone rocks has been studied. Both, the compressive and flexural strengths under confining pressure have been examined numerically. Two types of 2D-rock models have been studied are (200×200 mm2) and (200×700 mm2), respectively, for compression and flexural states with three sizes of openings having diameters of 10, 25, and 40 mm. The results of compression state showed that the strength reduces with existing opening and the reduction increases with the size of opening. The unconfined rock exhibited higher reduction in the strength than that of confined one with exists of opening. In case of flexural state, both compressive and tensile strengths increase with the increasing confining pressure, while they decrease with the opening size. At higher confining pressure, the size of opening has insignificant effect on the tensile strength. The tensile strength of the unconfined rock remains unchanged with increase in the size of opening beyond certain limit.
Penetration of warm heavy fuel oil waste in gypseous soil
Authors: Al-Obaidi A A , Homemade R A , Thieban D Kh 
Published: March 2020

Abstract
Gas power plants are the most common power plants, due to lower construction costs, shorter construction, and operating times than other power plants. However, the growing demands for more electrical power requires the construction or expansion of many power plants. The using of Heavy Fuel Oil (HFO) in the gas power plants needs a sequence of treating processes in a special treating unit. The HFO treating processes produce large quantities of the wastewater. Before treatment, the wastewater accumulated commonly in a large lagoon. During the high summer temperature, the stored wastewater in the lagoon, also, the concrete channels transferring it is warmed to a temperature of (60°C) as it exposed to the sun. In this research, an experimental device was manufactured to estimate the periods for percolation of contaminated waste material into different gypseous soil samples. In addition to the effect of wastewater on the characteristics of these soils, the results showed that as HFO waste temperature increases the percolation speed in the early stages of the percolation increases rapidly, and the degree of saturation of soil decreases. Also, increase in the HFO waste temperature decreases the settlement for soils of high and medium gypsum content, whereas it increases for soils with a low gypsum content.
Collapsibility of gypseous soil under suction control
Authors: Al-Obaidi Q A , Karim H H , Al-Shamoosi A A 
Published: March 2020

Abstract
Many geotechnical problems and foundation failures in engineering structures were recorded due to the presence of unsaturated gypseous soils. One of the main reasons, which introduced large volume change and collapse behaviour is the variation of suction pressure and water potential within the gypseous soil mass. In this study, Sandy gypseous soil from Al-Ramadi city (west of Iraq) with gypsum content of more than 70 % is used. In order to investigate the collapse deformation of gypseous soil under suction control by multi-steps wetting procedure, also the effect of sensors positions and applied vertical stress, a special soil-model device is designed and manufactured. In this device, high accurate and sensitive Tensiometers and Time Domain Reflectometry (TDR) sensors with an assistance of high quality Data logger are used for measuring and monitoring of matric suction and gravimetric water content of the soil sample during the deformation processes. The test results indicated that a large volume change and collapse deformation occurred upon reduction of matric suction. The void ratio dramatically reduced stepwise with reducing of matric suction by multi-steps wetting irrespective the value of applied vertical stress.
Comparative study of theoretical methods for estimating pile capacity using 1-g model pile tests in cohesionless soil
Authors: Abdul-Husain Husain Ali 
Published: March 2020

Abstract
The behavior of single pile is considered as the base of the most pile foundation design procedures. There are many different theoretical methods used to estimate the capacity of single pile embedded in cohesionless soil. In order to select the most accurate and reasonable method, 1-g model tests have been performed in this study. Different five procedures have been used to interpret the test results in order to select the suitable procedure. The statistical analysis showed that all procedures give approximate results except Chin’s procedure which yields inaccurate results with respect to the average value. Then, the results of five theoretical methods have been compared with the measured pile capacity from model tests (average value). The rank index analysis was conducted based on statistical parameters and probability distributions. The results of the analysis yielded that Coyle and Casttelo method gave the most accurate and reasonable results than the other theoretical methods considered in this study (Berezantsev’s method, Meyerhof’s method and traditional bearing capacity equation with some modifications). Finally, the author recommended using the two tangents procedure in interpreting of the pile test results. Also, the method proposed by Coyle and Casttelo can be used to estimate the pile capacity based on soil properties with accurate results.
Study the behavior of square footing in clayey soil subjected to vertical loading
Authors: Waheed Mohanned Q , Khalid Awf A , Rahil Falah H 
Published: March 2020

Abstract
Foundation is a part of the structure that transmits the load applied from the super structure to the soil below. Estimation of the bearing capacity of foundation is one of the most complicated problems in geotechnical engineering, therefore it provides a number of theories to estimate the bearing capacity. The purpose of this paper to study the behavior of model square footing in clayey soil subjected to vertical axial loading. The tests are conducted at three grades of undrained shear strength (Cu) of clayey soil which are (20 or 40 or 60 kPa). It is found that, in general, the load settlement curves of raft tests are non-linear hyperbolic shape without a well-defined peak load and the mode of failure is local shear failure in this type of soil, i.e. the behavior of this type of soil is strain hardening. Moreover, the bearing capacity factor (Nc) is equal to (2.8) where this value is not within the acceptable range of the bearing capacity factor (Nc) which ranges from (4 to 6.18) for saturated clay at (φ = 0). The ultimate load may occur at settlement more than (10%) of the width of the foundation which leads to make the settlement criterion control the allowable bearing capacity in design of shallow foundation in this type of soils.
Enhancement of porous asphalt mixture for resisting environmental conditions using modified asphalt
Authors: Ahmed Miran Bahyam , Abed Alaa Hussein , Al-Badran Yasir Mawla Hammood 
Published: March 2020

Abstract
Open-graded-friction-course (OGFC) is a hot asphalt mixture usually utilized as a private purpose wearing course, because of open graded asphalt mixture and aggregates skeleton (stone-on-stone) contact, it contains a relatively high air voids percent, after compaction which are permeable to water. In this research one sort of gradation was used (9.5 mm) NMAS for preparing the OGFC asphalt mixtures, penetration grade 40/50, crushed aggregate, asphalt content prepared with 4 % and up to 6 % by weight of mixture with 0.5 % increments. Optimum asphalt content (OAC) was selected based on these criteria: air voids content, asphalt draindown, permeability, and abrasion resistance (aged and un-aged) condition. The mix performance had been investigated by indirect tensile strength and moisture sensitivity measured according to the (AASHTO T283-14). Results illustrate that the increasing of asphalt binder content leads to decrease in the air voids content, abrasion loss and permeability values, while with draindown increase, conversely, the indirect tensile strength test (ITS) had been meaningfully increased for both conditions and this is a perfect signal of resistance against humidity susceptibility. It can be resolved that the increasing of asphalt binder % in OGFC asphalt mixture, leads to increase the thickness of asphalt binder covering around the aggregates. On the other hand the outcome indicated that the addition of 4 % styrene-butadiene-styrene (SBS) to asphalt mixture gradation equaled to “9.5 mm NMAS” tends to improve the mix properties and exhibit higher TSR by (18.5, 16.4 and 13.7) % increases, as compared with original asphalt; at asphalt content (5.1, 5.6 and 6.1) %, respectively. Based on the above evaluation, the use of SBS gives the asphalt mixture better volumetric and performance properties which improved the adhesion between aggregate and asphalt that leads to reduced stripping of HMA, horizontal deformation, and increased the tensile stiffness modulus value.
Comparative study for safety performance measures of signalized intersection sites
Authors: Abdul Majeed Raghad Zeki , Ewadh Hussein A 
Published: March 2020

Abstract
The decision on which safety performance measure to use for diagnosis of sites with probable to profit from safety improvements is a major factor in making the right decision for the guidance of resources. This study concentrated on introducing a quantitative comparison of sites according to four crash-based methods suggested in the Highway Safety Manual (HSM). Archived crash data for three years are obtained to conduct a comparison course. As a case study, the analysis and measure of safety for 9 four-leg signalized intersections in Baghdad city have been done independently using Empirical Bayes method (EB-method), observed Crash Frequency (CF), Crash Rate (CR) and Empirical Bayes Adjustment (EB-adj.) as safety performance measures in HSM. In this paper the EB-method is used as a benchmark for comparison. The safety measures are evaluated through rank correlation analysis while hazard location identification results are compared through the use of values rank-based mean absolute error. Quantitative evaluation tests showed that each of EB-adj and observed CF correlated well with EB-method while CR method exhibited poor performance in comparison with EB-method and was the worst in hazard location identification. This result is quite confusing since many agencies still depend on the CR method in traffic safety analyses.