scholarly journals Microstructure of CEM II/B-S Pastes Modified with Set Accelerating Admixtures

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6300
Author(s):  
Jan Pizoń ◽  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Compressive Strength ◽  
Reaction Rate ◽  
Calcium Nitrate ◽  
Xrd Analysis ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Hydration Reaction ◽  
Phase Reaction ◽  
Cement Pastes ◽  
Kiln Dust

The presented paper aims to describe the influence of accelerating admixtures on the properties and microstructure of cement pastes and mortars. Blended slag cement CEM II/B-S containing two different clinkers (differing amounts of siliceous and aluminous phases) and four types of accelerators (calcium nitrate, sodium hydroxide, cement kiln dust, and crystal seeds) were used in research. Compressive strength tests (after 12, 24, 48 h of curing), Scanning Electron Microscope (SEM) observations together with an Energy Dispersive Spectroscopy (EDS) analysis, Mercury Intrusion Porosimetry (MIP) tests, and X-ray diffraction (XRD) analysis were conducted. Results have shown that SEM and EDS examination of the microstructure of cement pastes modified with accelerating admixtures at the observed points did not reveal differences that would be sufficient to explain the changes in compressive strength. Still, the increase in amorphous phase content indicates a faster hydration reaction rate for all pastes modified with accelerating admixture. It is backed up also by lower non-hydrated compounds content. All admixtures accelerate the hydration reaction of calcium silicate phases of cement, but only NaOH and cement kiln dust (CKD) influence the aluminate phase reaction rate. The pore volume is independent of the clinker type, while the pore size distribution is not.

scholarly journals Use of Factory-Waste Shingles and Cement Kiln Dust to Enhance the Performance of Soil Used in Road Works

2009 ◽  
Vol 2009 ◽  
pp. 1-9 ◽  
Author(s):  
Aly Ahmed ◽  
Medhat Shehata ◽  
Said Easa
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Capillary Rise ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Fine Grained Soil ◽  
Stabilized Soil ◽  
Cement Manufacturing ◽  
Kiln Dust

An experimental work was conducted to study the use of factory-waste roof shingles to enhance the properties of fine-grained soil used in road works. Cement kiln dust (CKD), a cogenerated product of Portland cement manufacturing, was used as a stabilizing agent while the processed shingles were added to enhance the soil tensile strength. The effects of shingles on strength and stability were evaluated using the unconfined compressive strength, splitting tensile strength, and California Bearing Ratio (CBR) tests. The results showed that the use of CKD alone resulted in a considerable increase in the unconfined compressive strength but had a small effect on the tensile strength. The addition of shingles substantially improved the tensile strength of the stabilized soil. A significant reduction in the capillary rise and a slight decrease in the permeability were obtained as a result of shingle addition. An optimal shingle content of 10% is recommended to stabilize the soil.

Evaluation of Cement Kiln Dust-Stabilized Reclaimed Asphalt Pavement Aggregate Systems in Road Bases

2003 ◽  
Vol 1819 (1) ◽  
pp. 11-17 ◽  
Author(s):  
Ramzi Taha
Keyword(s):  
Compressive Strength ◽  
Unconfined Compressive Strength ◽  
Asphalt Pavement ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Dry Density ◽  
Reclaimed Asphalt Pavement ◽  
Reclaimed Asphalt ◽  
Kiln Dust ◽  
Road Bases

Road rehabilitation and reconstruction generate large supplies of reclaimed asphalt pavement (RAP) aggregate, and recycling into asphalt paving mixtures is the predominant application. Cement kiln dust (CKD), also known as cement bypass dust, is a by-product material generated during production of portland cement. In Oman, where recycling of pavement materials is not practiced, a first attempt was made at combining two by-product materials for use in road construction. Conservation of natural resources and preservation of the environment are two benefits that could be gained by reusing waste materials. The potential use in road bases of CKD-stabilized RAP and RAP with virgin aggregate mixtures was investigated. Physical, compaction, and unconfined compressive strength tests were conducted on RAP and virgin aggregate blends of 100% to 0%, 90% to 10%, 80% to 20%, and 0% to 100%. Samples were prepared using CKD at 0%, 3%, 5%, 7%, 10%, 15%, and 20% and were cured for 3, 7, and 28 days in plastic bags at room temperature. Results indicate that the maximum dry density and unconfined compressive strength of RAP generally increase with addition of virgin aggregate and CKD. The moisture content-dry density curves for CKD-stabilized RAP aggregate mixtures did not show a distinctive peak similar to that of the 100% virgin aggregate blend. Longer curing periods will produce higher strength values. CKD content of 15% seems to be the optimum for achieving maximum strength.

scholarly journals Physico-Mechanical Properties of Bricks Manufactured using Cement Kiln Dust

2020 ◽  
Vol 9 (3) ◽  
pp. 1804-1808
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Waste Management ◽  
Industrial Waste ◽  
Cement Content ◽  
Cement Industry ◽  
Cement Clinker ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
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.

scholarly journals COMPRESSIVE STRENGTH OF SELECTED FINE GRAINED SOILS TREATED WITH CEMENT KILN DUST AND CALCAREOUS FLY ASH

2020 ◽  
Vol 13 (1) ◽  
pp. 79-86
Author(s):  
Karolina KNAPIK-JAJKIEWICZ ◽  
Grzegorz GAJ ◽  
Adrian KOWALSKI ◽  
Sandra PRĘDKA
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Fine Grained ◽  
Kiln Dust

scholarly journals Microanalysis and Compactive Efforts Study of Black Cotton Soil Treated With Cement Kiln Dust

2019 ◽  
Vol 4 (1) ◽  
Author(s):  
Anigilaje B Salahudeen ◽  
Adrian O. Eberemu ◽  
Kolawole J. Osinubi
Keyword(s):  
Compressive Strength ◽  
Electron Microscope ◽  
Unconfined Compressive Strength ◽  
Laboratory Tests ◽  
Black Cotton Soil ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
British Standard ◽  
Kiln Dust ◽  
Scanning Electron

An expansive clay, also known as Black cotton soil (BCS) was treated with up to 10 % cement kiln dust (CKD) using three different compactive efforts; British Standard light (BSL), West African Standard (WAS) and British Standard heavy (BSH) energies. Laboratory tests were performed on the natural soil and CKD treated soil samples in accordance with BS 1377 (1990) and BS 1924 (1990) respectively with the aim of improving the deficient soil to meet engineering requirements. Preliminary evaluations on the natural black cotton soil showed that it fell under A-7-6 (16) using AASHTO classification and CL according to Unified Soil Classification System (USCS). Results of laboratory tests carried out on soil specimens show that the properties of the soil generally improved with CKD treatment. Peak unconfined compressive strength (UCS) values of 357.07, 382.49 and 528.82 kN/m2 and California bearing ratio (CBR) of 7, 10 and 19 % as well as resistance to loss in strength of 44, 55 and 55 % were recorded at 10 % CKD treatment, respectively, for BSL, WAS and BSH compactive energies. Reduction in the particle sizes with curing period was observed when samples were viewed through the scanning electron microscope (SEM). The study showed that CKD can be beneficially used to improve the subgrade of lightly trafficked roads and as admixture in lime stabilization during construction of flexible pavements over expansive soil.Keywords: California bearing ratio; Cement kiln dust, Durability; Expansive soil; Microanalysis, Unconfined compressive strength; Scanning electron microscope.

scholarly journals Feasibility of backfilling mines using cement kiln dust, fly ash, and cement blends

2018 ◽  
Vol 149 ◽  
pp. 01072
Author(s):  
H. Beltagui ◽  
M. Sonebi ◽  
K. Maguire ◽  
S. Taylor
Keyword(s):  
Compressive Strength ◽  
Alternative Fuels ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
X Ray Diffraction ◽  
Free Lime ◽  
Pulverized Fuel ◽  
Pulverized Fuel Ash ◽  
Cement Manufacturing ◽  
Kiln Dust

Cement kiln dust (CKD) is an industrial by-product of the cement manufacturing process, the composition of which can vary widely. Recent years of using alternative fuels have resulted in higher chloride and alkali contents within CKDs; as such, this limits the applications in which CKDs can be utilised. Using a CKD containing a high free lime content of 29.5%, it is shown that this CKD is capable of activating pulverized fuel ash (PFA) due to its high alkalinity, which can be utilised in low strength un-reinforced applications. One potential application involves the backfill of mines, reducing the need for continuous maintenance of the mine. This study focuses on the compressive strength achieved by various blends of CKD, PFA, and cement. Samples were hand mixed and compacted in 100 mm x 50 mm diameter cylinders, and unconfined compressive strength measurements taken at 28 and 56 days. The hydration products were assessed through the use of x-ray diffraction and thermogravimetric analysis. Aiming to maximise the use of CKD at a water to binder (w/b) ratio of 0.2, it was found that the maximum CKD content possible to achieve the required strength was 90% CKD blended with 10% cement.

Valorization of Metal Milling Waste in Cement Based Mortars Modified by Replacement of Cement Kiln Dust

2021 ◽  
Vol 47 (1) ◽  
pp. 19-30
Author(s):  
Bouzeroura-Mansour
Keyword(s):  
Cement Paste ◽  
Setting Time ◽  
Partial Replacement ◽  
Experimental Program ◽  
Cement Kiln Dust ◽  
Cement Kiln ◽  
Cement Pastes ◽  
Clean Environment ◽  
Materials Research ◽  
Kiln Dust

Recycling industrial by-product materials waste has become an attractive topic of materials research in civil engineering. These industrial by-product materials waste must be managed responsibly to insure a clean environment. Our research was conducted with the aim of investigating the effect of the addition of two industrial by product materials waste: metal milling waste (F) and cement kiln dust (CKD) in cement paste/mortar, as well as how to assess the influence of CKD substitution on the mechanical properties of cement pastes to create a new hydraulic binder based on partial replacement. An experimental program was conducted on samples of cement paste prepared at three CKD content (5%, 10%, 15% wt. of cement) and new mortars were prepared by: partial replacement of ordinary Portland cement by CKD at 5% by mass; and the simple addition of metal milling waste at three different percentages of (10%, 20%, 30% wt. of binder). Chemical, Micro structural analysis and mineralogical analysis have been carried out using XRD and FT-IR techniques, the mechanical strength, shrinkage, swelling, setting times, were analyzed.<br/> Test results after a 28-day hardening period indicated that when the increase in the CKD replacement, the expansion obtained in the mixed cement pastes increase and the initial and final setting time decreases. The improvement of the strength of cement kiln dust (CKD) in the mixed cement pastes is low, it was found that adding 5% of cement weight CKD is the appropriate percentage for utilizing in the manufacturing of mortars. the addition of metal milling wastes in mortars leads to a considerable improvement of mechanical strengths compared to the reference mortar. The strength increases when the percentage of Metal milling wastes additions increases until an optimum (20%).

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