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Waste material recycling in mortar production not only provides a promising resource for producing high-quality mortar, but it also aids in properly addressing the waste disposal issue. This study investigates the potential of utilizing blast furnace slag wastes as a supplementary cementitious material in blended cement-based mortars. The experimental program includes investigation of compressive strength of cement-based mortar composites contained different types and percentages of slag wastes. The mortar specimens were prepared and cured following related international standards. After curing, the compressive strengths of the tested specimens were assessed and compared with control specimens. The influence of the chemical composition of the investigated slag types on the resulted strength of the blended cement mortar was also discussed. Results of this study revealed that the chemical compositions of the raw slag wastes have significant effects on the pozzolanic activity of the produced slag. Slag samples contained higher percentages of calcium oxides present the most promising results regarding the production of supplementary cementitious material.

In any industrial or municipal population areas, the excess sewage sludge produced by wastewater treatment plant WWTP creates significant problems due to its growing quantity and possibly containing toxic materials or heavy metals. The concrete industry is one of the fields where wastewater sludge, as well as other wastes, could be utilized inefficient way. The inclusion of wastewater sludge in materials incorporated with cement reduces some of the costly and high energy stages of usage, and the obtained product is often safe and stable. Several studies promoted that the reuse of sludge in concrete can be an ideal solution to get rid of its negative effects, especially the hazardous ones, as it is an effective alternative to reuse the sludge for land applications. The main aim of this study is to present the recent methods of utilizing wastewater dried, dehydrated, and/or raw sludge in concrete industries. The present review revealed the difficulty of choosing the most general technique of utilizing sludge in the concrete industry, due to its various physical and chemical properties.

This research attempts to put a proposal Sustainable Design Development of the area around the Great Mosque & its Minaret, which it for many years has become a symbol of Iraqi architecture and its history as a result of the skill of Iraqi sculptors and architects in using local materials like bricks in their buildings. The research problem is a knowledge gap about the(SWOT) factors (strengths, weaknesses, opportunities, and threats) that faced area.. While Research methodology is descriptive and analytical. The Reasons for selecting this project is to raise the percentage of tourism in the area. Subsequently, to grow a good economic city; in addition to the importance of Samarra civilization in making it a destination for tourism for tours, students, poets, and others because it includes many cultural landmarks and needs a space to attract tourists and be a cultural outlet for the city as well as a recreational site embraces their activities and meet their needs. To the archaeological importance of the area near Al-Malwaiya, to attract tourists in the city, and it helps to identify the city heritage.

The effective linear attenuation coefficients and build-up factors for single shield of Al, Fe, Pb, and for multi-layer shield of Al-Pb, Al-Fe, Fe-Pb, Al-Fe-Pb as a function of shield thickness, atomic number, and order of the materials composing the shield are investigated for two photon energies of 0.662 MeV and 1.25 MeV. Two derived practical formulas to calculate the effective attenuation coefficient and build-up factor for multilayer shields are used. It is noticed that changing the order of the materials among the shield has no significant effect on the experimental result. Measurement agrees well with the trend of the suggested formulas for calculating the effective attenuation coefficient and the buildup factor. The linear attenuation coefficient is observed to have a strange dependency with the atomic number and photon energy. For single layer shield, the attenuation coefficient increases with decreasing atomic number at low photon energy and increasing with increasing atomic number at high photon energy.

Many past studies concerned about using of nanoclay (nC) particles as an active pozzolan to concrete and their influence on the physical and mechanical properties. In this study, the effects of various nanoclay particle sizes and dosages on the compressive and flexural tensile strengths of SCCs were investigated. Progressive nC percentages of 2%, 5% and 8% were replaced with cements and the produced SCCs were evaluated and compared with similar replacement levels of the metakaolin MK which have comparable chemical compositions. The produced SCCs were tested for compressive, flexural tensile and splitting tensile strengths in 28 and 90 days. Results indicated that nC replacement harmed all the studied mechanical properties at 28 days age. After 90 days, however, both compressive and tensile strengths of nC concretes show superior strengths than control concrete and also exceeded MK concretes made of equivalent replacement levels. This behavior demonstrates the pozzolanic activity of the nC particles at later ages and proved to be significantly more effective than early ages.

Present study aims to observe the consequence of varying the intensity of the accelerating impressed electrical current and situations of wetting-drying as hybrid accelerated corrosion regime on synthetically corroded concrete specimens, especially the loss of steel mass. Small-scaled reinforced concrete columns were fabricated and synthetically corroded by altered accelerating corrosion situations by applying an impressed current with intensity ranging between (50 and 500 μA/cm2). Moreover, the impressed current joined with two dissimilar durations of wetting-drying cycles for assessment. The steel mass losses during and at the end of the accelerated corrosion process were calculated, also, cracking configuration and damage shape were observed for accelerating corrosion. The outcomes designated that the hybrid method (impressed current joined with cycles of saline solution wetting and drying series) can be employed adequately to simulate the regular corrosion process in the reinforced concrete structure. The steel mass loss is mostly influenced by the intensities of the impressed accelerating current, while the crack appearance and the pattern of surface cracks, is influenced by wetting and drying cycles as well as the impressed accelerating current. Yet, increasing the current intensity produce a considerable growth in the cracking owing to the reinforcing steel corrosion in shorter stage.

Nitric oxide generated from various sources like car combustion is one of the most surrounding pollutants. Titanium dioxide considered an environmentally friendly active photocatalytics that can be used with building materials safely and effectively to react with nitric oxides in the presence of UV radiation from sunlight. To study the possibility for the reduction of air pollutants two strategies were adopted. First one included mixing of micro particles of TiO2 with cement paste in two percentages: 3% and 6%. In the second one mortar substrates were coated with micro TiO2 (mT) aqueous solution by either dipping or spraying coating method. A laboratory test procedure was adopted to assess the performance of the prepared photoactive specimens. The specimens were subjected to NO gas and there efficiency in gas removal was monitored with time. Results showed that coating strategy was more effective than mixing strategy in term of gaseous pollutants removal. The comparison between the two coating methods showed that the dipping method reached 98.08 % removal capacity and was better than spring method which reached 87.69 % only.

The elevated temperatures caused by fire affect the physical and chemical properties of the mortar and thus, influence its mechanical properties. This study presents the results of an experimental investigation on the mechanical properties and microstructure of cement based mortar composites contained polypropylene (PP) at high temperatures. The mortar was prepared and cured as per the relevant international standards. Upon curing, tested specimens were exposed to 250, 450, 600 and 900 °C for 2 h. The influence of the high temperatures on the physical and chemical changes of the blended cement mortar was also analyzed by Scanning Electron Microscopy. Mortar specimens exposed to different high temperatures were tested for compressive and flexural strengths, and compared with control specimens (i.e. unheated). Results revealed that even low fiber dosage of PP fibers with mortars was helpful in completely preventing explosive spalling due to significant increase of permeability. Mechanical results and microstructural analysis of mortar specimens showed that both compressive and tensile strengths were initially increased at 250C°, followed by considerable reduction at higher temperatures.

In Iraq pavements materials are exposed to various distresses due to the adverse environmental conditions and heavy traffic. The improvement of performance of flexible pavements is necessary for decreasing these distresses. The objective of this research is to improve the mixing efficiency of nano-silica particles with asphalt binder. Two mixer type (mechanical and high shear), rotational speeds (2000, 4000 and 6000 rpm), and mixing period (30 and 60 minutes) were assessed. Three nano-silica per cent 2%, 4%, and 6% by weight of asphalt were added and the asphalt binder mixtures were prepared by heating at mixing temperature 140 °C. Furthermore, comparisons were made to assess the modified asphalt binder characteristics such as penetration value, softening point, temperature sensitivity (penetration index), ductility and rotational viscosity. Results showed that the use of nano silica as an additive was useful in improving the asphalt binder characteristics. Generally, has been found that the penetration value decreased and softening point increased, as well as the viscosity, were increased and the temperature sensitivity was developed. Additionally, high shear mixing was more useful especially to obtain a good dispersion of nano silica powder in asphalt binder and got a homogenous composite material.

The aim of this study was to improve an effective approach to the processing of asphalt binder modified with micro-silica particles. Various mixer type (mechanical and high shear), revaluation rates (2000, 4000 and 6000 rpm), and two mixing time (30 and 60 minutes), were adopted. Three micro-silica contents 2%, 4%, and 6% by weight of asphalt cement were added. The asphalt binder was prepared at temperature of 140 °C. Comparisons were made to evaluate the properties of the modified asphalt binder such as penetration grade, softening point temperature, temperature sensitivity, rotational viscosity and ductility. Results of this study showed that the use of micro silica as a modifier was helpful in enhancing the physicals properties of the asphalt binder. In general, it was found that the penetration value decreased and softening point temperature, as well as the viscosity value, increased and the temperature sensitivity was improved. Furthermore, high shear mixing was more practical particularly to achieve a good dispersion of micro silica particles into asphalt binder and obtained a homogenous composite binder. Finally, the tested specimens showed 6% of micro silica was adequate to improve the physical properties of asphalt and become more suitable for constructing the highway pavements in hot weather conditions.

Dry-processed cement-based wood composites are reconstituted wood products with desirable longevity, fire resistance and life cycle cost. In this study, the effects of accelerated aging on the performance of CO2-cured cement-bonded wood particleboards were investigated. The accelerated aging conditions considered simulated natural aging phenomena. Repeated wetting–drying and freezing–thawing cycles led to increased stiffness and somewhat reduced toughness. X-ray diffraction and thermogravimetric analyses indicated that aging effects led to increased CaCO3 and decreased Ca(OH)2 contents in CO2-cured cementitious composites. Mercury intrusion porosimetry test results indicated that CO2 curing reduced the capillary pore volume in both unaged and aged boards.

Cement-bonded strawboard was developed as a new siding product with desired aesthetic attributes, workability and engineering characteristics. The high extractive and wax content of straw presents important challenges to production of cement-bonded strawboard. A broad variety of straw pretreatment techniques were evaluated for enhancement of straw compatibility with hydration of cement. Accelerated processing techniques involve applying pressure for densification and heating system were used. Use of admixtures and the specifics of strawboard production techniques were also essential to successful development of cement-bonded strawboard. The complementary use of these measures contributed towards development of cement-bonded strawboards which met the standard requirements for cement-based siding products and did not exhibit any degradation upon exposure to accelerated aging effects.

Cellulose fiber reinforced cement provides desired longevity, fire resistance and life-cycle economy, in addition to relatively high strength and toughness. An experimental investigation was conducted to assess the effect of accelerated CO 2 curing on the structure and durability of cellulose fiber cement composite. Carbonated boards showed reduced capillary porosity, increased CaCO 3 content and improved bonding of the cement based matrix to cellulose fibers. Under diverse accelerated aging effects, carbonated boards also provided improved longevity and weathering resistance. This could be attributed to the chemical stability of carbonated products and their reduced capillary porosity.

The objective of this paper is to inspect the effect of changing the density of the impressed current and wetting-drying condition on accelerated corrosion of reinforced concrete specimens by a galvanostatic method. Small-scale reinforced concrete columns were prepared and then artificially corroded by different setups of accelerated corrosion under an impressed current and also under different wetting-drying cycles for comparison. The density of the impressed current ranged between 50 and 500 µA/cm2 with different wetting-drying cycles periods. Corrosion current, and cracking were monitored throughout the accelerated corrosion period to determine the level of damage caused by the development of expansive reinforcement steel corrosion products, appearance of the first crack, and pattern of cracking.The results indicated that the galvanostatic method with wetting-drying sequences can be utilized effectively to simulate the normal corrosion of steel reinforcement in the concrete structure. The usage of different intensities of the current has no influence on the crack pattern. Though, increasing the current level leads to a substantial increase in the crack width due to corrosion of the steel reinforcement in a shorter time.

During the last years, the use of by-product materials, such as micro silica, mS, especially in the area of highway pavement materials has received increasing interest. The experimental work of this research focused on the investigation of the potential use of micro silica powder to enhance the rheological properties of asphalt cement binder. To achieve this aim, mixtures with various contents of micro silica and asphalt were prepared. The asphalt cement and micro silica were first tested. The micro silica powder has been mixed with the asphalt cement at a temperature of 140 °C by conventional mechanical mixer at 2000 rpm. Two mixing time durations were implemented to produce the modified asphalt mixtures: 30 and 60 minutes. The mS modified asphalt was then evaluated for the empirical physical and rheological properties including penetration value, softening point temperature, temperature susceptibility, Brookfield Rotational viscosity and ductility. The experimental work results showed that micro silica powder reduces penetration value and increases softening point temperature. Progressive increases in mS content were found to increase Brookfield Rotational Viscosity (RV) and tend to decrease the ductility of the studied specimens. The negative effects of added mS were more pronounced at values more than 4%. Finally, the increase in mixing time duration may slightly lead to good micro silica powder dispersion into the asphalt matrix, but it is the consumption of energy and cost.

This paper presents an experimental study of heat transfer between a shallow fluidized bed and the surface of a single horizontal tube and a tube bundle, which is immersed in it. Carbon, which is prepared from the Date stones, is used as a solid to be fluidized and a compressed air as an external fluid. The results showed that the overall heat transfer coefficient of tubes bundle, which immersed in fluidized bed is lower than single tube. The modified correlations and analysis are offered by experimental work, which shows the relations between heat transfer coefficient and superficial mass velocity. Key word: heat transfer - heat exchangers - fluidized bed heat exchangers

This paper describes the relationship between splitting tensile strength and compressive strength of self-consolidating concrete using data collected from laboratory specimens tested at standard conditions. The results were then compared with some expressions published in international literature. The investigated variables included: type of cement, percentage of nanosilica and percentage of microsilica as a cement replacement by weight. In spite of concrete not being designed to resist direct tension the knowledge of tensile strength is needed to estimate the cracking load. In the absence of test results an estimate of the tensile strength may be obtained by using the relationship proposed. The verification of the proposed formula based on experimental data was estimated by means of the integral absolute error (IAE). The output of this study has provided a better understanding of the correlation between splitting and compressive strengths of SCCs and the effect of some related variables on the resultant behavior, which has therefore, helped to generate new expression with better accuracy.

Volatile organic compounds (VOC) generated from various sources like car combustion is one of the most surrounding pollutants, which can be transferred from one form to another in the presence of sunlight. In the present work the ability of the reduction of VOC have been conducted on cementitious samples surfaces by using toluene as a pollutant gas and TiO2 as an environmentally friendly photocatalyst . Two coating methods have been used (dip and spray) with two types of aqueous solution, prepared by spreading 3g/L micro and nano TiO2 powder with deionized water. A laboratory test procedure was adopted to assess the performance of the coated specimens. The specimens were subjected to toluene gas and there efficiency in gas removal was monitored with time. Furthermore, contact angle for the coated samples was also examined to investigate the hydrophilicity of the coated substrate. The results showed that TiO2 give high activity and work as a good photocatalyst for mitigation of air pollutants, and that it could be used in different ways and concentrations to obtain better air quality and aesthetic building appearance. The observed coating efficiency in reducing the toluene was more pronounced in higher than lower gas concentrations for the micro coated samples with removal efficiency equals to 13% and 10% for dipping and spraying method, respectively. While the higher removal was about 20% for both nano dipping and nanospray methods for the inlet gas concentration 3ppm. This behavior reflects the beneficial effects of TiO2 coating procedure in highly pollutant environments, like Iraq.