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The objective of this research is to study the properties of CLSM that serve the same purpose as the soil used in roads besides determining the feasibility of incorporating cement kiln dust (CKD) in different proportions (5%, 10%, and 15%) by weight of cement. The research examines the possibility of using limestone powder (LSP) to produce CLSM mixtures. In this research, the fresh properties of CLSM (flowability, j-ring, v-funnel, density, segregation, and hardening time) were examined, besides determining the hardened properties (compressive strength, splitting tensile strength, flexural strength, density, and ultrasound pulse velocity) at 7 and 28 days ages. The fresh properties results showed that the mixtures containing (LSP), in which cement was replaced with CKD, fulfilled the requirements of CLSM used in roads. However, the hardening time increased with increasing the content of CKD due to the high content of lime and alkali present in CKD. The results of the hardened properties showed that the 28 -day compressive strength increased when replacing 5% of cement with CKD, but the strength decreased at (10% and 15%) CKD replacement compared to the control mixture (0% CKD). The splitting and flexural tensile strength of CLSM decreased at (5% and 10%) CKD replacement, while both strengths increased when 15% of the cement was replaced with CKD. The results of the ultrasound pulse velocity test, revealed that the velocity of wave transmission decreased with increasing the percentage of CKD replacement. [ABSTRACT FROM AUTHOR]

In current work, several laboratory investigations have been performed to recognize the effect of elevated temperatures and incorporating cement kiln dust (CKD) on the microstructural properties sand the bond strength of self-compacting concrete (SCC). In this research program, the characteristic of CKD and its effect as a partial replacement (10%, 20%, and 30% by weight) of Portland Cement (PC) in SCC were studied. Present study also explored the influence of high (elevated) temperatures (300°C, 500°C, and 700°C) in the electrical furnace-chamber with a heating treatment duration of 2 hours. Cement Kiln Dust (CKD) employed in this research work is considered an industrial by-product solid waste produced by the kiln of the cement manufacturing plant, which is collected using air pollution control devices. This ongoing study distinguishes the chemical, mineralogical and physical analytic tests such as XRF, SEM, XRD and PSD used for the raw powdered materials, CKD and PC. Empirical tests are managed to evaluate the mechanical and hardened features, including elastic modulus and pull-out tests. In this work, tests such as FESEM-EDS, XRD, TGA, and MIP were performed on SCC samples to investigate their mineralogical and microstructural aspects. In general, the investigations have shown that incorporating CKD in SCC mixes shows relatively equivalent strength of reference mix at ambient testing temperature. The microstructure analyses reveal valuable chemical and physical observations of the SCC matrix. After heating beyond 500°C, the chemical changes in the SCC samples with considerable development in mass loss, voids, and pores rather than micro-thermal cracks are also measured and monitored by microstructure tests. Interestingly, pull-out tests at ambient testing temperature indicate an excellent bond strength of SCC even with a 30% CKD replacement ratio. It was found that elevated temperatures had a greater effect on the bond strength. This study confirms that 20% CKD can be potentially utilized to make self-compacting concrete with almost the same strength as plain SCC. [ABSTRACT FROM AUTHOR]

Soft soils usually have shear strength values less than 200 kpa such as clay, silty clay, clayey sand, and soft organic clay. The presence of soft soils in engineering sites requires immediate remediation, which is either altering the site, or removing and replacing the existing soil. These solutions are not always applicable. Hence, other methods are needed which soil stabilization one of them. Soil stabilization is the modification of the physical and geotechnical properties of the weak, and soft soil either mechanically by compaction or chemically using chemical stabilizers. This paper presents a comprehensive review on the stabilization of soft soils by utilizing sustainable stabilizers which are waste and by-product materials such as ground granulated blast slag (GGBS), activated GGBS and cement kiln dust (CKD). These stabilizers are utilized as replacement to the traditional binders (cement and lime). The results indicate that GGBS alone gives only a slight enhancement because of the glassy phase of this material. Nevertheless, activation of GGBS by other materials improves the physical and geotechnical characteristics of soft soils substantially while the use of CKD gave remarkable enhancement to the soft soil characteristics. The physical properties are evaluated by Atterberg limits and compaction parameters, and the geotechnical characteristics are evaluated by the unconfined compressive strength (UCS) test. [ABSTRACT FROM AUTHOR]

Swelling soils are found in many regions of the world, including Iraq. Swelling soil contains minerals that can absorb water easily, which leads to an increase in its volume, and this is the reason for swelling soil. The aim of this study is to improve the properties of swelling soils, reduce the cost of paving construction, and clean the environment from industrial waste by using waste materials in soil stabilization. Wasit Governorate in Iraq was selected as a study area because it contains swelling soil. Where the clay soil was soft, puffy, and looked like popcorn, after the free swell test, the soil swell rate was 70%. The material used is PVC waste of small dimensions (2-3 mm) mixed with cement kiln dust. 10% of waste PVC with 5, 10 and 15% of cement kiln dust was used to treat the swelling soil. The liquid limit is reduced from 66% to 42,34,27%, the plastic limit decreases from 34 to 29, 22, and 19%, and free swelling decreases from 70% to 55,40,32%, respectively. The results showed an increase in the dry density when adding the same percentages, as well as an increase in the optimum water content. Soil dry density of 1.48 g/cm3 became 1.75 g/cm3, 1.84 g/cm3, and 1.88 g/cm3 and 6,8,10, and 12% optimum water content, respectively. The CBR for soil was 2%. The test results showed the best ratio The results showed a 10% PVC with 10% CKD, which gave the best results during a different curing period. The results were 6.3, 7.5, and 10% with a curing period of 96 hours, 7 days, and 28 days, respectively, with the optimum percentages being 10% PVC and 10% CKD. [ABSTRACT FROM AUTHOR]

The use of waste by-products materials such as cement kiln dustand reclaimed asphalt pavementin soil stabilization aims to improve the mechanical properties of soils in which more sustainable soils can be existed. The influence of wetting and drying cycles on the strength of soil stabilized by cement kiln dust and reclaimed asphalt pavement as well as the investigations of the microstructure of such blends are evaluated in this study. High plasticity clayey silt soil was under investigation. The results showed that there was a significant increase in the unconfined compressive strength, which reflected the soil strength. In contrast to control soil samples, which collapsed in the first cycle of wetting and drying, soil mixtures stabilized by cement kiln dust and reclaimed asphalt pavement passed the cycles of wetting and drying with a constant volume and no dramatic weight loss. The weight loss of the mixture of soil with 20% cement kiln dust and 35% reclaimed asphalt pavement was 2.64%, as a lowest loss. Moreover, the unconfined compressive strength of samples stabilized by cement kiln dust significantly increased after conducting wetting and drying tests compared to that of tested samples before the test. The unconfined compressive strength of soil stabilized by 20% cement kiln dust increased to 5.85 MPa after performing the durability test compared to its value of 2.68 MPa before the test. On the other hand, there was a slight change in the unconfined compressive strength value of soil stabilized by mixtures of cement kiln dust and reclaimed asphalt pavement after conducting the durability test. The formation of compounds with cementitious properties in the structure of stabilized soils was proven by microstructural analysis using scanning electron microscope. [ABSTRACT FROM AUTHOR]

The article presents the results of studying the economic and technological foundations for improving the production and operational performance of equipment related to the production of cement mass. It is shown that it is expedient to manufacture the bodies of furnaces made on the basis of a rotating principle with helical surfaces, the centers of curvature of which are located inside the body. The use of the proposed rotary screw equipment in the production of cement mass creates the conditions for increasing the speed of rotation of the kiln body by dozens of times, increasing productivity, reducing the size of kilns and reducing production costs. [ABSTRACT FROM AUTHOR]

The idea of the research revolves around the use of by-products of industries (cement kiln dust, fly ash) and their consumption in production of a binder using in manufacture of sustainable concrete with good specifications that exceed the specifications of Portland cement concrete. On the other hand, reducing the manpower, using equipment and tools in casting or compacting of concrete is another factor of sustainability. In this paper, the possibility of using cement kiln dust (CKD) as a percentage of fly ash in the production of alkali activated self-compacting concrete (AASCC) and its effect on the fresh properties, compressive and splitting tensile strength of the resulting concrete was studied., It was observed that the replacement ratios of cement kiln dust CKD instead of fly ash did not affect the workability properties for resulting concrete, where the proportion of (10%) of CKD replacement caused increase in compressive and tensile strengths about 5%, while, (20, 30)% caused decrease in the compressive and splitting tensile strengths about (30, 44)% respectively. [ABSTRACT FROM AUTHOR]

The purpose from testing studies to discovery out the efficiency of CKD from Al-Muthana city Iraq government to removal Methylene Blue Dye (MB) in simulated textile wastewater generated from Al-Diwaniya textile factory in Al-Diwaniya city Iraq government. The wastewater discharge from textile industries that contain methylene blue dye is removed by adsorption through cement kiln dust, therefore, was studied this case. The best electrostatic action is the basic action between methylene blue and cement kiln dust. As cement kiln dust has especially nanostructure properties and the negative charge for his plane, the positive charge for methylene blue compound ability for simply adsorb above it. [ABSTRACT FROM AUTHOR]

Expansive soils (also known as shrink/swell soils) are encountered in various regions of the world. The behavior of this type of soils is quiet complex. As they fall in the category of ‘problematic soils’. Swelling and shrinkage in soils occur as a result of the seasonal variations in climatic conditions which affect the water retention in soils. Climate change prediction shows that these problems may get worse in the future. This leads to more interest in this subject during the last few years, with an increasing attention, in experimental investigations, modeling, and field investigations. In order to reduce the pollution and to keep the environment clean and sustainable, waste and recycled materials are used in the current study to improve the undesirable characteristics of expansive soil samples in the lab. Therefore, several laboratory tests have been carried out to proof that using of a significant by-product material of the cement manufacturing process the cement kiln dust (CKD) is contributed in improving the properties of an expansive soils, silica fume material (a waste industrial material ) is also be useful in reducing the effect of the shrink- swell in soils, and finally using a high density polyethylene polymer (PEHD) is showed a significant decreasing in swelling deformation and increasing in the unconfined compressive strength with some other considerable changes in the previous soil properties. The Polyethylene polymer may used to enhance the behavior of expansive soil and reduced the most common problem related to this soil (swelling potential). As well as, silica fume could be effectively used to improve the properties of expansive soil with specific limits. Therefore, the main aim of this study is to observe the ability of CKD with silica fume and polyethylene polymer in improving the characteristics of expansive soil. The results shows that using additives 10% of CKD, 5, 10, 15% of silica fume, and 5, 8, 10% of PEHD decreased liquid limit and plasticity index of an expansive soil, increased its plastic limit values, and also contributed in stabilizing the expansive soil by significantly reducing it swelling ability. The liquid limit and plasticity index are reduced from 88% to 53.2% and from 67.8% to 29.6% respectively by adding 10%CKD, 10%Silika fume and 10% of PEHD. And the swelling potential is decreased from 21.23% to 2.1% by adding these additives. [ABSTRACT FROM AUTHOR]

The adsorption of Chromium trivalent Cr(III) has been studied. Its equilibrium isotherm has been measured. The isotherm was determined by stirring 3 g of Cement Kiln Dust (CKD), with 250 ml of a chromium solution (from a tannery effluents wastewater) of initial concentrations 2336 and 4320 mg/l respectively. The stirring rate was used at constant rate of 1200 rpm and the temperature maintained at 25±2° C. A contact time of around 60 min was required to achieve equilibrium. The experimental isotherm results have been fitted using Langmuir, Freundlich, Temkin and Dubinin-Radushkevich equations. The monolayer adsorption capacity is 303 mg Cr(III) per g of Cement Kiln Dust. A comparison of kinetic models applied to the adsorption of Cr(III) ions on the adsorbent was evaluated for the pseudo first order, the pseudo second order, Elovich and intraparticle diffusion kinetic models, respectively. Kinetic parameters, rate constant, equilibrium sorption capacities and related correlation coefficients for each kinetic model were calculated and discussed. All the results show that the pseudo second order kinetic model was found to correlate the experimental data well and removal operation studied gave high removal efficiency. That’s indicate to the high capacity of CKD to sorption of Cr(III) from wastewater effluents. [ABSTRACT FROM AUTHOR]