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Chee Ban Cheah - One of the best experts on this subject based on the ideXlab platform.
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the engineering performance of concrete containing high volume of ground granulated blast furnace slag and pulverized fly ash with polycarboxylate based superplasticizer
Construction and Building Materials, 2019Co-Authors: Chee Ban Cheah, Ling Ling TiongAbstract:Abstract This experimental investigation was conducted to study the Development of ternary blended concrete that containing high cement replacement level of ground granulated blast furnace slag (GGBS) and pulverised fly ash (PFA) with the polycarboxylate-based superplasticizer (PCE). In order to make this GGBS-PFA ternary blended cement system at high cement replacement level suitable for practical production, measures need to be developed to enable acceptable Early Strength Development for concrete produced using the materials to be achieved. An optimum combination ratio of GGBS and PFA in ternary blended cement system was prior determined in this study for consistent production control. Besides, an optimum dosage of M-PEG type PCE was determined by using marsh funnel test as well for the compatible use in this GGBS-PFA ternary blended cement system. Experimental results indicated that the optimum ratio for GGBS and PFA was 4:1 at 50% cement replacement level by total binder’s weight while the optimum dosage of PCE was 1.0% by total binder’s weight in this ternary blended cement system. Mechanical properties such as flexural and compressive Strengths and UPV were then examined on hardened concretes at 7, 28, 56 and 90 days. In addition, Scanning Electron Microscopy (SEM) techniques combined with Energy Dispersive X-ray (EDX) had been performed for better understanding the phase changes and microstructures Development of maturing GGBS-PFA ternary blended cement system. In this study, the GGBS-PFA ternary blended concrete with 60% cement replacement achieved the optimum performance with the inclusion of 1.0% of PCE superplasticizer by total binder’s weight.
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the use of high calcium wood ash in the preparation of ground granulated blast furnace slag and pulverized fly ash geopolymers a complete microstructural and mechanical characterization
Journal of Cleaner Production, 2017Co-Authors: Chee Ban Cheah, Muhammad Hasnolhadi Samsudin, Mahyuddin Ramli, Wei Ken PartAbstract:Abstract As concern regarding global environmental issue grows, there is an emerging interest to substitute conventional ordinary Portland cement by using geopolymer composite as binder matrix in concrete. However, there are two main components that become a barrier in industrialization of geopolymer are the high content of chemical activator and requirement for post fabrication heat treatment which is an energy intensive process. The study investigate the hybridization of three industrial byproducts namely Ground Granulated Blast Furnace Slag, High Calcium Wood Ash and Pulverized Fly Ash activated with reduced level of alkaline activator and produced without any thermal treatment and possesses adequate mechanical performance mortar for industrial application. Besides, the properties of low energy hybrid geopolymer mortar were assessed based on the mechanical and microstructure aspects. Test specimens were evaluated in terms of standard consistency, setting times, compressive Strength, flexural Strength, ultrasonic pulse velocity, dynamic modulus of elastic, and microstructure Development. The inclusion of Pulverized Fly Ash at the content of 10–60% by binder weight does reduce the water demand and significantly prolonged the setting times of hybrid geopolymer paste. Enhanced modulus of elasticity, ultrasonic pulse velocity, compressive and flexural Strength were observed for hybrid geopolymer concrete with Pulverized Fly Ash content of 40–80% by binder weight compare to control mixture, 0% PFA. Besides, from Scanning Electron Microscope micrograph and Energy Dispersive X-ray analysis geopolymer paste matrix indicated the formation of geopolymeric products of C-A-S-H and N-A-S-H that contributes to the Early Strength Development on geopolymer mixture contains 0% up to 60% percentage of Pulverized Fly Ash.
Wei Ken Part - One of the best experts on this subject based on the ideXlab platform.
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the use of high calcium wood ash in the preparation of ground granulated blast furnace slag and pulverized fly ash geopolymers a complete microstructural and mechanical characterization
Journal of Cleaner Production, 2017Co-Authors: Chee Ban Cheah, Muhammad Hasnolhadi Samsudin, Mahyuddin Ramli, Wei Ken PartAbstract:Abstract As concern regarding global environmental issue grows, there is an emerging interest to substitute conventional ordinary Portland cement by using geopolymer composite as binder matrix in concrete. However, there are two main components that become a barrier in industrialization of geopolymer are the high content of chemical activator and requirement for post fabrication heat treatment which is an energy intensive process. The study investigate the hybridization of three industrial byproducts namely Ground Granulated Blast Furnace Slag, High Calcium Wood Ash and Pulverized Fly Ash activated with reduced level of alkaline activator and produced without any thermal treatment and possesses adequate mechanical performance mortar for industrial application. Besides, the properties of low energy hybrid geopolymer mortar were assessed based on the mechanical and microstructure aspects. Test specimens were evaluated in terms of standard consistency, setting times, compressive Strength, flexural Strength, ultrasonic pulse velocity, dynamic modulus of elastic, and microstructure Development. The inclusion of Pulverized Fly Ash at the content of 10–60% by binder weight does reduce the water demand and significantly prolonged the setting times of hybrid geopolymer paste. Enhanced modulus of elasticity, ultrasonic pulse velocity, compressive and flexural Strength were observed for hybrid geopolymer concrete with Pulverized Fly Ash content of 40–80% by binder weight compare to control mixture, 0% PFA. Besides, from Scanning Electron Microscope micrograph and Energy Dispersive X-ray analysis geopolymer paste matrix indicated the formation of geopolymeric products of C-A-S-H and N-A-S-H that contributes to the Early Strength Development on geopolymer mixture contains 0% up to 60% percentage of Pulverized Fly Ash.
G N Angelopoulos - One of the best experts on this subject based on the ideXlab platform.
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valorisation of electric arc furnace steel slag as raw material for low energy belite cements
Journal of Hazardous Materials, 2011Co-Authors: Remus Ion Iacobescu, D Koumpouri, Yiannis Pontikes, R Saban, G N AngelopoulosAbstract:Abstract In this paper, the valorisation of electric arc furnace steel slag (EAFS) in the production of low energy belite cements is studied. Three types of clinkers were prepared with 0 wt.% (BC), 5 wt.% (BC5) and 10 wt.% (BC10) EAFS, respectively. The design of the raw mixes was based on the compositional indices lime saturation factor (LSF), alumina ratio (AR) and silica ratio (SR). The clinkering temperature was studied for the range 1280–1400 °C; firing was performed at 1380 °C based on the results regarding free lime and the evolution of microstructure. In order to activate the belite, clinkers were cooled fast by blown air and concurrent crushing. The results demonstrate that the microstructure of the produced clinkers is dominated by belite and alite crystals, with tricalcium aluminate and tetracalcium-alumino-ferrite present as micro-crystalline interstitial phases. The prepared cements presented low Early Strength Development as expected for belite-rich compositions; however the 28-day results were 47.5 MPa, 46.6 MPa and 42.8 MPa for BC, BC5 and BC10, respectively. These values are comparable with OPC CEMI 32.5 N (32.5–52.5 MPa) according to EN 197-1. A fast setting behaviour was also observed, particularly in the case of BC10, whereas soundness did not exceed 1 mm.
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Valorisation of electric arc furnace steel slag as raw material for low energy belite cements
'Elsevier BV', 2011Co-Authors: Iacobescu, Remus Ion, Koumpouri Dimitra, Pontikes Yiannis, Saban Rami, G N AngelopoulosAbstract:In this paper, the valorisation of electric arc furnace steel slag (EAFS) in the production of low energy belite cements is studied. Three types of clinkers were prepared with 0 wt.% (BC), 5 wt.% (BC5) and 10 wt.% (BC10) EAFS, respectively. The design of the raw mixes was based on the compositional indices lime saturation factor (LSF), alumina ratio (AR) and silica ratio (SR). The clinkering temperature was studied for the range 1280–1400°C; firing was performed at 1380°C based on the results regarding free lime and the evolution of microstructure. In order to activate the belite, clinkers were cooled fast by blown air and concurrent crushing. The results demonstrate that the microstructure of the produced clinkers is dominated by belite and alite crystals, with tricalcium aluminate and tetracalcium-alumino-ferrite present as micro-crystalline interstitial phases. The prepared cements presented low Early Strength Development as expected for belite-rich compositions; however the 28-day results were 47.5 MPa, 46.6 MPa and 42.8 MPa for BC, BC5 and BC10, respectively. These values are comparable with OPC CEMI 32.5 N (32.5–52.5 MPa) according to EN 197-1. A fast setting behaviour was also observed, particularly in the case of BC10, whereas soundness did not exceed 1 mm.status: publishe
Taegyu Lee - One of the best experts on this subject based on the ideXlab platform.
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effect of electrolyzed alkaline reduced water on the Early Strength Development of cement mortar using blast furnace slag
Materials, 2020Co-Authors: Taegyu Lee, Suna Kim, Sungyu ParkAbstract:This study evaluated the use of electrolyzed alkaline-reduced water instead of an alkaline activator for the production of a strong cement matrix with a large blast furnace slag replacement ratio. The flexural and compressive Strength measurements, X-ray diffraction analysis, and scanning electron microscopy images of the cement matrices produced using electrolyzed alkaline-reduced water and regular tap water, and with blast furnace slag replacement ratios of 30 and 50% were compared to a normal cement matrix. The cement matrix produced using electrolyzed alkaline-reduced water and blast furnace slag exhibited an improved Early age Strength, where hydrate formation increased on the particle surface. The cement matrix produced using electrolyzed alkaline-reduced water exhibited a high Strength Development rate of over 90% of ordinary Portland cement (OPC) in BFS30. Therefore, the use of electrolyzed alkaline-reduced water in the place of an alkaline activator allowed for the formation of a very strong cement matrix in the Early stages of aging when a large blast furnace slag replacement ratio was used.
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The Effects of Fineness and TEA-Based Chemical Admixture on Early Strength Development of Concrete in Construction Site Applications.
Materials (Basel Switzerland), 2020Co-Authors: Taegyu Lee, Jaehyun Lee, Hyeonggil Choi, Dong-eun LeeAbstract:This study examines effects of cement fineness and chemical admixtures of Early Strength agents on the Early Strength Development of concrete. Three cement types were selected, namely ASTM type-I ordinary Portland cement (OPC), fineness ordinary Portland cement (FOPC), and ASTM type-III Early Portland cement (EPC), and the mixing proportions of concrete were set by adding a triethanolamine-based chemical admixture to FOPC. The evaluation items considered in this study included raw material analysis, compressive Strength, and maturity (D∙h). The time required for the Development of concrete Strength of 5 MPa in the three cement types was estimated and compared. The results revealed that using FOPC enhances the Strength Development of concrete owing to its higher fineness and SO3 content compared to OPC. In addition, it has been observed that using both FOPC and TCA yields a similar performance to that observed using EPC, in light of the improved Early Strength Development at low temperatures.
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effects of accelerators and retarders in Early Strength Development of concrete based on low temperature cured ordinary portland and calcium sulfoaluminate cement blends
Materials, 2020Co-Authors: Taegyu Lee, Jaehyun Lee, Hyeonggil ChoiAbstract:In this study, experiments were performed on the applicability of mortars and concretes based on calcium sulfoaluminate (CSA) binders to facilitate the Early Strength Development of ordinary Portland cement (OPC) under low-temperature conditions. An optimum mixture of CSA was evaluated to improve the Early Strength of OPC, and the effects of accelerators and retarders on this mixture were examined to demonstrate the applicability of the resulting concrete mixture. Furthermore, mixture applicability was validated by producing concrete at the Remicon Batcher plant and performing numerical simulations. As observed, the optimum CSA substitution rate for the realization of Early Strength was 17% of the total unit binder amount with CaO/SO3 and SO3/Al2O3 ratios of 1.9 and 1.25, respectively. Evidently, CSA in combination with Na2SO4 as an accelerator promoted the Early Strength of concrete with OPC and secured its constructability using additional retarders to control the quick setting of concrete. Additionally, the activation of initial hydration at low temperatures yielded a compressive Strength of 5 MPa/12 h or higher for the resulting concrete mixture.
Kaimi Shih - One of the best experts on this subject based on the ideXlab platform.
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value added recycling of construction waste wood into noise and thermal insulating cement bonded particleboards
Construction and Building Materials, 2016Co-Authors: Seaso S Che, Daniel C W Tsang, Chi Su Poo, Kaimi ShihAbstract:Large amounts of waste wood formwork from construction sites end up with landfill disposal every day. This study aims to develop a practicable technology for recycling construction waste wood into formaldehyde-free cement-bonded particleboards that have value-added features of high Strength, light weight, and thermal/noise insulation for reuse in building and construction applications. The mineralogy and microstructure of particleboards were characterized by X-ray diffraction, thermogravimetry, and mercury intrusion porosimetry analyses. Among the mineral admixtures, chloride accelerated precipitation of oxychlorides while sulphate produced calcium sulphoaluminate for promoting Early Strength Development. The use of 2% CaCl2 proved to be sufficient for improving the wood-cement compatibility. At wood-to-cement ratio of 3:7 by weight (i.e., 3:1 by volume), cement hydrates in the porous structure ensured acceptable dimensional stability (<2% swelling). By adjusting the water-to-cement ratio to 0.3 and density of the particleboards to 1.54 g cm−3, the volume of capillary pores was effectively reduced from 0.16 mL g−1 to 0.02 mL g−1. The more compact microstructure contributed to high fracture energy at 6.57 N mm−1 and flexural Strength of 12.9 MPa. Using the above optimal production conditions, the particleboards complied with the International Standard (9 MPa) while enabling reuse as light-weight structure. The particleboards also manifested outstanding structure-borne noise reduction (at 32–100 Hz) and low thermal conductivity (0.29 W m−1 K−1), suggesting potential application as acoustic and thermal insulating materials. Preliminary cost-benefit analysis illustrated economic viability of the proposed approach. Therefore, technological innovation is crucial for delivering an eco-friendly solution to waste wood recycling for the building and construction industry.
