Amounts Of Cement Kiln Dust Research Articles

Influence of Cement Kiln Dust on Long-Term Mechanical Behavior and Microstructure of High-Performance Concrete.

Cement production in the world market is steadily increasing. In 2000, it was 1600 million tons, while as of 2013, the annual amount exceeded 4000 million tons. The burning of cement clinker is associated with the generation of waste. It is estimated that the amount of cement kiln dust (CKD), during combustion, reaches about 15-20%, which means 700 million tons per year. However, not all types of by-products are reusable due to high alkali, sulfate, and chloride contents, which can adversely affect the environment. One environmentally friendly solution may be to use CKD in the production of high-performance concrete (HPC), as a substitute for some of the cement. This paper presents a study of the short- and long-term physical and mechanical properties of HPC with 5%, 10%, 15%, and 20% CKD additives. The experiments determined density, water absorption, porosity, splitting tensile strength, compressive strength, modulus of elasticity, ultrasonic pulse velocity, and evaluated the microstructure of the concrete. The addition of CKD up to 10% caused an increase in the 28- and 730-day compressive strengths, while the values decreased slightly when CKD concentration increased to 20%. Splitting tensile strength decreased proportionally with 5-20% amounts of CKD regardless of HPC age. Porosity, absorbability, and ultrasonic pulse velocity decreased with increasing cement dust, while the bulk density increased for HPC with CKD. Microstructure analyses showed a decrease in the content of calcium silicate hydrate (C-S-H), acceleration of setting, and formation of wider microcracks with an increase in CKD. From the results, it was shown that a 15% percentage addition of CKD can effectively replace cement in the production of HPC and contribute to reducing the amount of by-product from the burning of cement clinker.

The Effect of CKD and RAP on the Mechanical Properties of Subgrade Soils

The construction of pavement layers on subgrade soil with good characteristics decreases the thickness of these layers, which in turn lowers the cost of building and maintaining roadways. However, it is impossible to avoid constructing pavements on unsuitable subgrade due to a number of limitations. Using conventional additives like lime and cement to improve subgrade properties results in additional costs. As a result, utilizing by-products (cement kiln dust and reclaimed asphalt pavement) in this field has benefits for the environment, economy, and technology. Large amounts of cement kiln dust (CKD), a by-product material, are produced in Portland cement factories. On the other hand, large amounts of reclaimed asphalt pavement (RAP) are accumulated as a result of the rehabilitation of old roads. This paper discusses using CKD and RAP to improve the characteristics of poor subgrade layers by conducting a series of Unconfined Compressive Strength (UCS) and California Bearing Ratio (CBR) tests on samples of natural soil and soil stabilized with different percentages of CKD and RAP with different curing times to investigate their impacts on soil properties. The curing was carried out by wrapping the stabilized samples with several layers of nylon and then placing them in plastic bags at room temperature. The compaction results illustrated that the addition of CKD increases OMC and decreases MDD, in contrast to RAP, which decreases OMC and increases MDD. The addition of CKD and RAP led to a significant and unexpected increase in the CBR values. The results show that the soaked and unsoaked CBR values improve from 3.4% and 12.1% for natural soil to 220.1% and 211%, respectively, after adding 20% CKD and curing the samples for 28 days. Also, the addition of 25% RAP to soil-20% CKD blend increased the soaked and unsoaked CBR values to 251% and 215%, respectively. All the additions resulted in a significant reduction in swelling.

An investigation of the mechanical properties of ternary blend cement pastes containing a large amount of cement kiln dust

An investigation of the mechanical properties of ternary blend cement pastes containing a large amount of cement kiln dust

An investigation of the mechanical properties of ternary blend cement pasts containing a large amount of cement kiln dust

An investigation of the mechanical properties of ternary blend cement pasts containing a large amount of cement kiln dust

Evaluation of environment and economy viable recycling cement kiln dust for use in green concrete

The use of industrial plant wastes such as fly ash (FA) and cement kiln dust (CKD) is an optimal solution to improve some of the fresh and hardened properties of concrete and also a rational choice to reduce the effect of carbon dioxide in the construction industry. In this study, different amounts of CKD (0–40%), as a waste material, and FA (0–30%) as a pozzolanic material, were used as a single and hybrid replacement of cement. Then, Taguchi method with two parameters of water to binder ratios and cement replacement ratio was used to determine the optimal mixing designs before construction from environmental and economic points of view. Comparison of the Taguchi method and experimental results for selecting the most favorable mixture designs showed that Taguchi method exhibited suitable choices in the range of optimal experimental results with regard to the initial parameters. This means that if the water-to-cement, CKD-to-cement, and the fly ash-to-cement ratios were 0.45, 9%, and 14%, respectively, it would be possible to obtain the best possible values for the strength to price, CO2 emission factor, and the standard deviation ratio.

Combined effect of cement kiln dust and calcined dolomite raw on the properties of performance magnesium phosphate cement

Starting from a local material dolomite, Magnesium Phosphate Cement (MPC) materials were prepared using partially calcined dolomite and ammonium dihydrogen phosphate. The MPC were prepared with varying amounts of cement kiln dust (CKD) in the range of 0–30 % weight. The influence of CKD addition on the characteristics of the cement compositions was explained in terms of struvite phase formation as well as the remained CaCO3. The obtained results demonstrated the benefit of the CKD as an additive in MPC that uses partially calcined dolomite as source of MgO leading to promoting the struvite formation. A mechanical tensile strength of 2.95 MPa was obtained and compared to results reported in the literature. Moreover, the magnesia was not dead burned as previous reported in many studies. The obtained results showed that these cements, advantageously, can be used at lower cost for the replacement of the actual commercial cement.

Physico Mechanical Properties of Bricks Manufactured using Cement Kiln Dust

the actual increase in global industrial production and manufacturing, produces a continuous increase in amount of industrial waste and continues to emit an all-time high amount of air pollutants and greenhouse gas emissions. To fight and mitigate these phenomena, proper Waste Management became the pillar of most environmental strategies worldwide. By reduction of consumption, re-use of goods and recycling of products, waste management aims to preserve the resources and to protect the environment. The Cement industry is one of the most important industrial sectors for society development; however it also has significant negative environmental impacts due to its emissions and production of waste. Cement kiln dust (CKD) is an industrial waste or by product which results from cement manufacturing. CKD is fine grained, solid, highly alkaline particulate material chiefly composed of oxidized, anhydrous, micron-sized particles collected from electrostatic precipitators during the production of cement clinker. This research examines the effects of using large amounts of CKD to replace the cement content in the fabrication of solid cement bricks. It is triggered by the quadruple objectives of reducing the amount of cement consumption, disposing efficiently of its industrial waste and producing economic bricks with safe strength. The purpose of this paper is to assess the properties of solid cement bricks containing different amounts of CKD. Cement bricks produced using different amounts of CKD were tested to find their properties and final comparison has been made to identify the effect of using different CKD/Cement ratio on the performance of bricks compared to the reference specimen produced using cement only with no CKD. For the brick mixes, Ordinary Portland cement (OPC), with two cement content of 200kg/m3 and 250kg/m3 were used throughout this investigation. The physical properties; unit weight, water absorption and mechanical properties; compressive strength, flexural strength, of the produced bricks were determined. Results showed that partial replacement of OPC with CKD reduces the brick compressive strength by 18% to 23% for CKD/OPC ratio of 30% and by 36% for CKD/OPC ratio of 50% and in all cases the strength remains largely higher than the standard limit for load bearing bricks.

Clay soil stabilization using cement kiln dust

This research investigated the suitability of cement kiln dust (CKD) on the stabilization of clayey soil extracted along a failed road section of Sango, Ota. Since CKD does not need any further processing or treatment, it is cheap as it is a waste product from cement production and can be utilized in powdery form. The suitability of CKD as a stabilizer is dependent on its performance on problematic soil. For this study, it was mixed with clayey soil in varying proportions of 7.5, 10, 12.5 and 15%. For each combination, several geotechnical tests were carried out. The result shows that the unsoaked CBR of the clay soil increased from 1.49 to 28.6%, and thus indicates that the soil mixed with 10% CKD showed the best mechanical improvement after a curing period of 7 days. Other curing periods were observed. In addition to CBR improvement, other tests such as Atterberg limits, Proctor compaction, and free swell, tests revealed that the geotechnical properties of the stabilized soils increased with an increase in the amount of CKD by dry weight of the soil. It is noted that the use of CKD at 10% was more economical and environmentally beneficial. This research shows the beneficial use of industrial wastes such as CKD in the stabilization of soils, which is line with sustainable waste management practices.

Investigation of adding cement kiln dust (CKD) in ordinary and lightweight concrete

Cement kiln dust (CKD) is one of the most important waste materials in the cement industry. The large amount of this material, has encouraged researchers to propose new ways to recycle and reuse it. In this paper, effects of adding cement kiln dust to the ordinary Portland cement, on the physical and mechanical properties of ordinary and lightweight concrete were investigated. Results showed that concrete containing CKD, presents lower workability and modulus of elasticity; however, improvements in strength was observed by adding particular amounts of CKD. Eventually, it was found that adding 10% of cement weight CKD is the appropriate percentage for utilizing in manufacturing ordinary and lightweight concrete.

Influence of Tensile Strain at Failure on Flexural Properties of a Cementitiously Stabilized Subgrade Soil

AbstractFlexural properties of subgrade soils play an important role in the overall performance of pavements. In this study, a series of laboratory tests and finite-element analysis were conducted to evaluate the effect of the stress-strain behavior of cementitiously stabilized soil (CSS) on its flexural fatigue life. Three different amounts of cement kiln dust (CKD), namely 5, 10, and 15% (by weight), were mixed with soil, and beam specimens were prepared using these three mixes. Modulus of rupture (MoR) tests were conducted on the prepared specimens to measure flexural strength and tensile strain at failure. Four-point bending beam fatigue tests were conducted on CSS specimens to evaluate their flexural modulus and fatigue life of each mix. Also, finite-element models of the MoR tests were developed using a concrete damage plasticity model for the CSS material. The MoR test results showed that the flexural strength increases with an increase in the amount of CKD. However, the failure strain was not foun...

Engineering Properties of Cement Kiln Dust-Modified Soils in Western Washington State

The Portland cement manufacturing process produces considerable amount of cement kiln dust (CKD). While many facilities are able to reuse a significant portion of CKD in their production lines, a large percentage is removed as industrial waste and placed in landfills. Because of the large amount of material potentially available for use, and in an effort to cut disposal costs, alternative and beneficial uses for CKD need to be investigated. This study presents experimental results of the use of CKD in modification and stabilization of soils from the Aberdeen and Everett areas in the state of Washington. These soils are typically wet of the optimum water content and pose problems during geotechnical construction. CKD was added in percentages of 5, 10, 15, and 20% by dry weight of the soils. Laboratory tests, including drying rate of the soils, Atterberg limits, standard proctor and unconfined compressive strength were conducted. Results of the investigation showed significant improvement in drying rate and unconfined compressive strength of the CKD treated specimens as the percentage of CKD increased. It was also found that lower percentages of CKD can be used for modification purposes, whereas higher percentages of CKD can be used for both modification and stabilization purposes in geotechnical construction.

Influence of cement kiln dust on the physical properties of calcium lime mortars

This work investigates the influence of cement kiln dust (CKD) on the properties of mortars made with a non-hydraulic binder of high available-lime content (calcium lime—CL), in order to further recycle industrial waste. Physical properties of CKD-CL90 mortars with increasing CKD content were compared to those of feebly-hydraulic lime (NHL2) and CL90 mortars. This paper concludes that, despite the CKD in this study being partially inert, the abundant reactive, free lime provided by the CL90 binder has enabled formation of hydration products. The strength development, rising proportionally to the amount of CKD when addition is over 5%, and the reduction in porosity/suction of the CKD/CL90 mixes, support the occurrence of hydraulic set. The high alkalinity of the CKD/CL90 system; the high specific surface of the CKD particles and the presence of amorphous reactive silica further support the presence of hydraulic set. Results evidenced that CKD addition significantly increased the mortar’s water demand simultaneously enhancing compressive strength and bulk density, and decreasing porosity and capillary suction. These effects can be ascribed to both the gain of packing density induced by the CKD particles, and the formation of hydration phases within pores and the space originally filled with water. Finally, this work concludes that the physical properties of CKD/CL mortars including at least 20%CKD are comparable to those of feebly hydraulic lime mixes, however, fracturing by shrinkage (due to high water demand) and damage related to sulphur, chlorine and alkali content need to be investigated before CKD/CL mixes are advised for application.

Influence of cement kiln dust substitution on the mechanical properties of concrete

Large quantities of cement kiln dust (CKD) are produced during the manufacture of cement clinker by the dry process. The technical and economical problems that arise for the semi-manufacture of raw materials used, energy and transportation of dust from the plant to outside, as well as the severe pollution to the surrounding atmosphere show the necessity of utilizing cement dust as one of the main objectives of our investigation. The cement dust contains a mixture of raw feed as well as calcined materials with some volatile salts. The aim of the present work is to study the effect of cement dust substitution instead of ordinary Portland cement (OPC), blast furnace slag cement (BFSC), and sulphate resistance cement (SRC) on the mechanical properties of some concrete mixes containing them, and also, to determine the optimum quantity of CKD which could be recycled in the manufacture of these types of cements. Useful conclusions and recommendations concerning the use of different amounts of CKD in the production of some blended cements as a partial substitution from different types of cements were obtained.