Kiln Dust Research Articles

Improving Soft Subgrade Stability Using a Novel Sustainable Activated Binder Derived from By-Products

Soft soil concerns, due to high compressibility and low bearing capacity, prompted an investigation into stabilizing clay soil. Traditionally, binder including cement or lime has been used as stabilizers though a current requirement of alternatives is stem from environmental concerns. The study focused on the viability of using a novel binary activated blended binder composed of environmentally friendly materials, namely ground granulated blast furnace slag (GGBS) activated by cement kiln dust (CKD). The experimental work included investigating the impact of the developed binders on the Atterberg limits, standard Proctor compaction, California Bearing Ratio (CBR), unconfined compressive strength (UCS), and field-emission scanning electron microscopy (SEM)/energy-dispersive X-ray spectroscopy. CBR tests were conducted after 7 days of curing or soaking, while UCS and SEM analyses were conducted after 7 and 28 days of curing. A fixed binder ratio of 9% was maintained, with GGBS blended at 25%, 50%, and 75% with CKD. For comparison, samples of untreated and treated soils with unary binders from GGBS and CKD were also prepared. Results indicated that activated binders notably decreased soil plasticity and maximum dry density, while elevating optimum moisture content, CBR, and UCS, especially in later stages of treated soil and unary GGBS binder. Unary CKD binder exhibited a similar trend to activated binders. The activating of 25% GGBS with 75% CKD provided the optimum binder which increased the mechanical strengths by about 6 times than untreated soil. SEM revealed substantial formations of C-S-H and C-A-H gel, along with ettringite, intensifying with time. This research provides viable outcomes for stabilizing clay soil using environmentally friendly binders, demonstrating significant improvements in soil properties, particularly when using the binary activated blended binder consisting of GGBS and CKD.Graphical

Design and Cost Analysis of Flexible Pavement Constructed Using Rice Husk Ash and Brick Kiln Dust

Design and Cost Analysis of Flexible Pavement Constructed Using Rice Husk Ash and Brick Kiln Dust

Predictive Pattern of Undrained Shear Strength in Stabilized Sulfur Rich Silty Soil Based on Binder and Initial Mixing Water Content

A laboratory investigation was conducted to identify principal variables-initial mixing water content, porosity, and binder content- impacting undrained shear strength (qu) of stabilized sulfur-rich silty soil. An equation for predicting qu of stabilized soil was established based on the experimental data. Initially, samples were prepared with soils sample with different initial water and binder contents. Multicem, a binder consisting of a mix of cement and cement kiln dust, was added to the samples. Three different percentages of Multicem were mixed at five different soil water contents to measure qu of stabilized mixtures to understand how water content and porosity levels in the samples affect the performance of the binder and their combined impact on the strength of the samples. The soil-binder mixtures were compacted and subsequently cured in laboratory-controlled environment. The prepared samples were tested in uniaxial compression test apparatus. The results evidenced that binder content and corresponding porosity affect the strength of specimens at an equal water content. The results showed that at equal initial mixing water content, the qu of a sample increased by increasing binder content. Furthermore, it was observed that increase of binder content has a reverse effect on porosity. It was appeared lowering the soil water content, initially increased the strength until an optimum water content. Further lowering water content increased the porosity and consequently decreased qu of samples. Moreover, a ratio of porosity/volumetric binder content was chosen to evaluate the impact of these two variables on strength of samples. This study showed that qu is an exponential function of porosity/binder volumetric content ratio which depends on initial mixing water content of mixtures. It was shown at water content lower than the optimum, results of stabilization are more effective than in soil at higher water contents. Therefore, reducing the water content and thereby porosity has more significant effect on improving qu than increasing the binder content.

Knowledge, attitudes and practices regarding respirable silica exposure and personal protective equipment use among brick kiln workers in Nepal

ObjectivesBrick kiln workers in Nepal are a neglected population who are exposed to high respirable silica concentrations, and few use interventions to reduce exposure. We aimed to characterise the prevalence...

Effect of Surface Hydrophobization on the Durability of Concrete with Cement Kiln Dust

Effect of Surface Hydrophobization on the Durability of Concrete with Cement Kiln Dust

Using a Laboratory Model Test to Assess the Collapsibility of a Gypseous Soil Improved with Geogrid and Cement Kiln Dust

Using a Laboratory Model Test to Assess the Collapsibility of a Gypseous Soil Improved with Geogrid and Cement Kiln Dust

Adsorption of 2,4-Dichlorophenoxyacetic Acid Herbicide from Aqueous Solution by Using Cement Kiln Dust Solid Waste

Adsorption of 2,4-Dichlorophenoxyacetic Acid Herbicide from Aqueous Solution by Using Cement Kiln Dust Solid Waste

Performance analysis of self compacting concrete by incorporating fly ash, coal gangue powder, cement kiln dust and recycled concrete powder by absolute volume method

To achieve environmental sustainability and improve material characteristics, this study examines the performance of self-compacting concrete (SCC) that incorporates different industrial by-products, including fly ash (FA), coal gangue powder (CGP), cement kiln dust (CKD), and recycled concrete powder (RCP). Through an experimental program, the research evaluates the fresh and hardened properties of SCC as well as its microstructural features. Slump flow, T50, and V-funnel tests were utilized to evaluate the fresh characteristics, while the compressive strength was the main emphasis of the hardened property at 7, 14, and 28 days of curing periods. To clarify the internal structure of the material and the pozzolanic processes taking place therein, further microstructural investigations were carried out using scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR) spectroscopy. Due to pozzolanic reactions and the densification of the microstructure, the results show that adding these industrial by-products not only makes SCC more workable but also gradually increases its compressive strength. In particular, the study shows that combinations with FA, CKD, and RCP perform better than CGP in terms of flowability and strength development. The results highlight the technical advantages of improving concrete qualities through material innovation, in addition to the possible environmental benefits of recycling waste materials in construction.

Cement kiln dust and polypropylene fiber in expansive clay improvement

For civil engineers, expansive soils pose a great deal of difficulty because of their sensitivity to volume changes with different moisture levels. These difficulties are compounded by the widespread occurrence of swelling clay, which can seriously harm infrastructure, especially in arid or semi-arid areas. The geotechnical qualities of these soils have been improved through the use of various additives and techniques, resolving this problem and making the soils suitable for building. Numerous stabilization techniques, nevertheless, may have negative environmental effects. Therefore, it is imperative to investigate the use of local waste or by-products to stabilize soil in order to preserve the environment and lower stabilization costs, especially in road construction projects.To address these issues, an experiment was conducted to determine how locally obtained cement kiln dust (CKD), both alone and combined with polypropylene fibers, affected the properties of plastic clay soil, also referred to as expansive clay from Cheffia.The main objective of this study is to assess how well different CKD percentages (from 5% to 25%) stabilize soil while improving its mechanical and physical properties. The study also aims to explain how the addition of polypropylene fiber affects the unconfined compressive strength and compaction behavior of the soil in the optimal CKD-soil mixture. The results of the analysis show that the addition of cement kiln dust (CKD) significantly improved the studied soil's workability, compaction, and strength. Additionally, adding polypropylene fibers strengthens the clay's resistance to compression, which presents encouraging opportunities for reducing the difficulties brought on by expansive soils in civil engineering applications.

Effectiveness of lime kiln dust on swelling of subgrade expansive soil

BackgroundThe structure of flexible or rigid pavement built on expansive subgrade soil that has a volumetric change is vulnerable to many problems that might cause failure. Pavement and construction became more durable and economical by enhancing the quality of subgrade expansive soil. Solid waste recycling has become very popular recently as a means of attaining sustainable waste management, so using lime kiln dust (LKD), which is a by-product of quick lime production, to treat expansive soil in pavement subgrades. This research describes the effect of LKD on the chemical composition, strength, and swelling of high and low-plastic clay that were extracted from two sites. The minimum LKD required for treating expansive soils was determined by using the Eades and Grim pH test. From tests, it was found that the addition of LKD increased the shrinkage limit by a range (250–500)% and decreased the plasticity and swelling potential by between (50 and 100)% of expansive subgrade soils. The strength according to CBR, increased approximately by 150% for CL soil and 800% for CH soil.ResultsThe optimal percentage of LKD for CH soil is 6%, and for CL soil, it is 2%. The plastic limit increased by 50% for CH soil at 6% LKD. On the other hand, CL soil became non-plastic at 4% LKD. With an increase in the percentage of LKD, it led an the increase in the shrinkage limit by 500% in CH soil and 250% in CL soil. The free swell decreased by 50% in CH soil and 100% in CL soil. The swelling pressure decreased by 50% for two expansive soils. CBR increased by 800% in CH soil and by 150% in CL soil.ConclusionThis work found that the addition of LKD improves the physical, chemical, and mechanical properties of expansive subgrade soil.

Mineralogy and geotechnical properties of alkaline-activated kaolin with zeolitic tuff and cement kiln dust as landfill liners

Mixtures of variable proportions of kaolin, quartz sand, zeolitic tuff, and cement kiln dust were blended while adding an 8 M sodium hydroxide (NaOH) solution to allow alkali-activation of kaolin and achieve the optimum strength. This study investigated the mineralogy, microstructure, and geotechnical properties of the prepared mixtures. The aim was to produce a sustainable, environmentally friendly landfill liner. The samples were compacted in stainless steel molds to a maximum dry density and optimum moisture content, extruded from the molds, and left to cure in an oven at varying temperatures from 40°C to 80°C for 24 h. The investigations included XRD, SEM, unconfined compressive strength, and hydraulic conductivity tests. Test results showed the development of a hydroxysodalite binder due to the alkali reaction of kaolin, which caused an increase in strength ranging from 20 to 25 MPa depending on the curing temperature. Alkaline activation was effective even at temperatures as low as 40°C. A mixture of 100 units of kaolin, 45 units of sand, 45 units of zeolitic tuff, and 10% by weight cement kiln dust (CKD) with an 8 M sodium hydroxide activator was found to best achieve the required strength and hydraulic conductivity of 10−9 m/s for the landfill liner. The zeolitic tuff with high cation exchange capacity, available in the mixture, absorbs contaminants in the leachate and prevents pollution of the groundwater. The use of cement kiln dust contributes to enhancing strength and solving an acute environmental problem.

Determination of Radium concentration and Radon Exhalation Rates Using CR-39 Detector for Different Geopolymer Cement Samples Containing Industrial Wastes

Natural material like metakaolin, along with industrial wastes such as fly ash (FA), cement kiln dust (CKD), and ground granulated blast furnace slag (GGBFS), are being used to develop new affordable and environmentally friendly construction materials (Geopolymers) that result in reduced carbon dioxide emissions. Geopolymers are gaining attention for their ability to effectively remove organic and inorganic contaminants from wastewater, including dyes and heavy metals. However, the study of the radiation properties of eco-friendly geopolymer cement materials has received little attention. To address this gap, conducted a previous study to examine the radiation properties of different geopolymer cement samples. In this study, the analyzed the radon concentration, radium concentration, and annual effective dose of various pre-treated geopolymer cement samples that contained industrial wastes from dyes and heavy metals. By using the CR-39 detector as a passive technique for this examination. In the pretreated geopolymer cement samples, we used three types of reactive dye effluents - reactive black 5 (BD), reactive red 195 (RD), and reactive yellow 145 (YD) in the presence of heavy metals (Cu2+, Cd2+, and Pb2+). Based on our research, the concentration of radon ranged from 2.69 to 212.42 Bq m-3. The sample with the lowest value of radium concentration was labeled as (10) (GGBFS), while sample (9) (SF10-YD-Cu2+) had the highest value. Found that the annual effective doses were within the range of the world average for indoor and outdoor 1.55and0.58mSvy−1 respectively, except for sample 9 (SF10-YD-Cu2+) which had the highest radium concentration. The pretreated geopolymer cement mixes containing different dye effluents and heavy metals were found to be safe for use in construction areas, except for sample 9 (SF10-YD-Cu2+). Recommend using sample 9 (SF10-YD-Cu2+) only for public highways, bridges, and other well-ventilated buildings.

Key durability characteristics of GGBS-cement kiln dust based concretes

With the advent of global warming, the concrete industry has the potential to drive the future of construction through sustainable cement technologies. These technologies rely on activation of industrial waste materials, such as Cement Kiln Dust (CKD) and Ground Granulated Blast Furnace Slag (GGBS) while Portland cement (PC) content is maintained at a minimum, resulting in concrete products of reduced embodied carbon footprint. This work reports on the durability of mixes made from PC, GGBS and CKD at incremental contents of 40-75% and 0-35% for GGBS and CKSD, respectively, in an attempt to identify durable formulations while maintaining blends at low embodied CO2 emissions in the Sultanate of Oman. Dimensional changes, sulfate and chloride resistance, as well as surface resistivity were determined and compared to those of a PC-based concrete formulation. The results suggest that, when GGBS and CKD were incorporated within the mix at an optimum content of 55% and 20% respectively, the concretes appeared to have exhibited promising durability characteristics which could lead towards the material’s implementation within a greater context.

Improvement of properties of black cotton soil subgrade through lime kiln dust and sand stabilization

ABSTRACT This study investigated improving black cotton soil, known for poor construction qualities, by mixing it with lime kiln dust (LKD) and sand. Lab tests analyzed how these additives impacted the soil’s properties. Results showed untreated soil had high swelling potential and low strength. Adding a combination of 30% sand and 3% LKD significantly improved strength, reduced swelling, and lowered the plasticity index. This combination met Ugandan Ministry of Works and Transport subgrade specifications, making it an optimal stabilizer for black cotton soil.

Cement Kiln Dust as Partial Replacement of Cement for Improvement of Sabkha Soils for road application

Salt-encrusted desert flats or sabkha soil, which particularly formed in arid and semi-arid zones, have raised a noticeable concern because of low bearing capacity and high compressibility. this study is aimed to explore the feasibility of stabilizing Omani sabkha using environmentally friendly stabilizer through Cement Kiln Dust (CKD). Untreated and treated sabkha were characterized using standard proctor compaction test, unconfined compressive strength (UCS) and California Bearing ratio test (CBR). Results show that utilizing 7.5% binder that contained 50% Cement Kiln Dust improved the overall properties of sabkha soil and it can be used as sub-base layers.

Mechanism of improvement and best-fit models for the prediction of geotechnical properties of lime stabilized expansive soil used in pavement subgrade

The performance of a pavement mainly depends on the quality of the subgrade layer. Expansive soils (ES) are extensively found worldwide including Pakistan. The inadequate strength and swelling behaviour of these soils are the main problems in any road construction project. Several researchers in the last decades have attempted to improve expansive soil utilizing various materials such as lime, brick kiln dust and fly ash. The purpose of this research was to evaluate the effect of lime on the engineering properties of the ES of a highway subgrade in the Sialkot region of Pakistan. The influence of different lime dosages (0%, 2%, 4% and 6%) at curing ages (1, 7, 14 and 28 days) has been examined by pH tests, plasticity tests, compaction tests, unconfined compressive strength (UCS), free swell index, and California Bearing Ratios (CBR). A field CBR and plate load test (PLT) on the natural soil and optimum lime-treated soil with various curing periods have been carried out for applicability as subgrade material. The test findings demonstrated that higher lime dosages increased the strength and ultimate bearing capacity (𝑞𝑢𝑙𝑡) of improved ES and at the same time decreased the free swelling index (FSI), optimum moisture content (OMC), maximum dry density (MDD) and permanent deformation of the subgrade soil. The UCS values of soil treated with 2%, 4% and 6% lime increased almost by 324%, 523%, and 249% for unsoaked samples and 285%, 351% and 231% for soaked samples respectively as compared to the plain soil at 28 days curing period. The laboratory CBR values significantly increased 2.35-8.50 times and field CBR improved 5.6 times as compared to the plain soil. The 𝑞𝑢𝑙𝑡 of lime-treated soil increased by 162% as compared to the plain soil and permanent deformation reduced from 33 mm to 2 mm after 28 days. Furthermore, equations were developed to estimate the best fit for the prediction of various geotechnical parameters and coefficient of determination (R2 ) values for all equations were found higher than 0.90. From the results, it has been concluded that adding the optimum lime content of 4% by weight satisfies the requirement for the subgrade construction of highways and the developed expressions can provide a scientific basis for estimating the geotechnical parameters.

Reviewing the enhancement of expansive soil through different waste material blending

This review paper examines the efficacy of blending various materials for the enhancement of expansive soil behavior. Expansive soils, characterized by volumetric changes in response to moisture fluctuations, present significant challenges in engineering projects. The review explores the utilization of waste additives such as quarry dust, sawdust ash, glass powder, stone powder, marble dust, Lime and Polypropylene Fiber, plastic waste strips and waste brick powder Oil Shale Ash, cement kiln dust as well as innovative solutions including organic compounds and nano-materials. The effectiveness of each material blend in mitigating issues such as swelling, shrinkage, and cracking is analyzed. The study underscores the importance of material selection and optimal blending techniques in achieving desired improvements in soil properties. Additionally, the paper highlights the need for continued research and innovation to develop sustainable solutions for managing expansive soils in construction and geotechnical engineering endeavors.

Research on the strength reduction mechanism of Cement Kiln Dust (CKD) – Portland cement systems from macroscale and nanoscale

Cement kiln dust (CKD) is a solid waste produced by the thermal decomposition of materials during the production of cement clinker. Theoretically, CKD can potentially be utilized to replace cement materials, which can reduce the expend for natural resources. However, the detailed mechanism of CKD on the source of strength reduction from macroscale and nanoscale is still unclear. This study focus on revealing the strength reduction mechanism of CKD-Portland cement. The results show that the strength reduction is dominated by the sulfate composition contents, which is not relative with the generation of lower elastic modulus C-S-H. And the higher ratio of S/Si is not conducive to enhancing strength. At the microscale, both the crystalline hydrates contend and the corresponding morphology are depended on the CKD dosages. And at the nanoscale, the generated C-S-H is characterized as a stacking structure. The average elastic modulus of generated C-S-H is 33.0 GPa. The relative contents of VLD, LD, HD and UHD C-S-H of the CKD-Portland samples are 4.7%, 22.0%, 37.9% and 35.2%, respectively. Furthermore, the CKD promoted the reaction rate and accelerated the hydration process. This study provides valuable insights into the application of CKD in cement-based material.

Economic and environmental assessment of industrial wastes stabilized clay and sand soil subgrades using experimental and theoretical approaches

The objective of the present study was to increase the strength and stiffness of silty clay and silty sand subgrades for building economic and sustainable asphalt pavements. Advanced cyclic load tri-axial (ACLT) and California bearing ratio (CBR) tests were performed to obtain the experimental and theoretical resilient modulus (MR) of the soil subgrades, respectively. In addition, the impact of the stabilization of the plasticity and compaction characteristics of the soil subgrades was determined. The insight into the mechanism of the stabilization was obtained by determining the mineralogical and microstructural properties of the stabilized soils through X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM) tests, respectively. The combined inclusion of 20% brick kiln dust and 20% pond ash resulted in 186% increase in the CBR, 224% increase in the experimental MR, 96% increase in the theoretical MR, 2.07 times higher pavement service life, 23% savings in cost, and 28% reduction in the CO2 emissions associated with pavement construction. The enhancement in the CBR and MR of the soils was attributed to the increased inter-particle friction, improved particle size distribution in stabilized clay and sand, and a concurrent reduction in the plasticity of clay. The study highlights the real-world usage of the ACLT test to get the real MR of soil subgrade rather than the over-estimated theoretical MR. For precise estimation of MR from CBR, a correlation between CBR and experimental MR was established.

Effect of silica fume substitution by limestone powder and cement kiln dust on the shrinkage, durability, and sustainability of UHPC.

Silica fume is usually used in UHPC, three times more than that for normal concrete, to enhance mechanical properties and durability. However, silica fume (SF) is an expensive material and has high production costs. This work is aimed at investigating the shrinkage and durability performance of previously developed UHPC mixtures utilizing the two calcareous waste materials, namely limestone powder (LSP) and cement kiln dust (CKD), by partially replacing the silica fume. The optimally selected mixtures of UHPC, having flow and strength above the minimum required, were used for detailed investigation in terms of shrinkage and durability characteristics. The results showed that by replacing SF with up to 20% of LSP and up to 20% of CKD, the mechanical properties of UHPC remained satisfactory compared to the control mixture with 100% SF. However, the ultimate shrinkage was higher for mixtures incorporating LSP or CKD, indicating the need for more volume of steel fibers to compensate for the shrinkage strains. The developed UHPCs also exhibited high resistance against reinforcement corrosion and sulfate attack, making them suitable for use in aggressive exposure conditions. However, special attention needs to be paid to the CKD content, where it is recommended to limit the content of CKD to about 15% or less to control the durability performance of the UHPCs. In addition, the sustainability analysis of developed UHPC mixtures was carried out using the life-cycle assessment and eco-strength intensity index. The results indicated that the UHPC mixtures possess a higher life-cycle and are therefore more sustainable.