Warakulwit C.,Kasetsart University |
Yadnum S.,Kasetsart University |
Paluka V.,Kasetsart University |
Phuakkong O.,Kasetsart University |
And 4 more authors.
Chemical Engineering Journal | Year: 2014
In the course of the production of cement clinker, a high amount of carbon dioxide (CO2) is released, causing an undesirable impact on the environment. The in situ conversion of this CO2 to carbon nanomaterials that can reinforce cement would be a novel approach delivering both on-site CO2 removal and high value-added cement products. The production of carbon nanomaterials over cement clinker via oxidative dehydrogenation of acetylene by CO2 is investigated. Chemical vapor deposition experiments were performed at 450-800°C. Carbon nanofibers (CNFs) were obtained as the major product at 575-725°C. This temperature range strongly relates to the temperatures at which active Fe3+ species in clinker are abundant, indicating that these species are responsible for the reaction. The presence of CO2 can effectively preserve the catalytic domains. As a consequence, with CO2 the CNF diameters increase gradually in the temperature range of 600-700°C and yet the product yield is higher. The characteristics and yield of CNFs strongly depend on the reaction temperature. Thus, fine-tuning this parameter is a simple and practical strategy for controlling the CNF diameter and amount in the CNF/clinker composite material and in turn the mechanical properties of the cement. The proper operating temperature with respect to CNFs with diameters in the order of ten nanometers and the maximum yield is 625°C. By performing additional experiments we later found that approximately 10% of CO2 produced by the cement industry is potentially reduced via the synthesis technique presented in this work. © 2014 Elsevier B.V.
Wansom S.,National Metal and Materials Technology Center |
Janjaturaphan S.,National Metal and Materials Technology Center |
Sinthupinyo S.,Siam Research and Innovation Co.
Cement and Concrete Research | Year: 2010
Rice husk ash (RHA) has long been known to possess a pozzolanic property. The abundance of rice husk as agricultural waste makes RHA the most promising candidate to be used as a supplementary cementitious material (SCM) in many rice-exporting countries. The use of RHA as an SCM helps reduce the use and thus the production of cement that involves great energy consumption and CO 2 emission. To promote the use of RHA as an SCM, a method to assess its pozzolanic activity is needed for the process of optimizing the burning conditions and/or selecting RHA from uncontrolled burning of rice husk as biomass fuel. The present work aims to use impedance spectroscopy to characterize pozzolanic activity of RHAs prepared on a pilot scale. The method is based on the rate of the normalized conductivity change of the Ca(OH) 2 + RHA paste, d(σ/σ0)/dt, during the first 24 h of hydration. The measurement was found to be sensitive to the unburnt carbon content in the 6-8 wt.% range and the amorphous SiO2 content (regardless of the unburnt carbon content). When used to evaluate two separate groups of RHAs, each with comparable unburnt carbon contents, the method gives very high correlation coefficients to the strength activity index at 3, 7, and 28 days. However, the correlation coefficients fall significantly when RHAs with vast difference in the unburnt carbon contents are considered together. The method thus proves to be powerful for evaluation of the pozzolanic activity of RHAs with comparable carbon contents. © 2010 Elsevier Ltd. All rights reserved.
Pimraksa K.,Chiang Mai University |
Chindaprasirt P.,Khon Kaen University |
Huanjit T.,Chiang Mai University |
Tang C.,Siam Research and Innovation Co. |
Sato T.,Tohoku University
Journal of Cleaner Production | Year: 2013
Bottom ash (BA) from Mae Moh lignite power plant was used to synthesize zeolite and zeolite-like materials. Low temperature synthesis (100-110 °C) was completed using SiO2 to Al2O3 with molar ratios of 2.94 and 2.92, respectively. Factors investigated that affect synthesis include particle size distribution, pretreatment of BA, concentration of alkali solution and liquid to solid ratio. The synthesized product qualities were characterized by mineralogical composition, morphology, specific surface area, pore size, pore volume and cation exchange capacity. Natrolite-K zeolite (NAT-K) was obtained with a solution of BA and 7 M KOH. Zeolite-like material (potassium aluminosilicate hydrate: KASH) was obtained using very fine BA and 9 M KOH solution. The NAT-K, KASH and BA powders were used to replace type I Portland cement at 0, 5,10,20 and 30% by weight to produce composite materials for heavy metal encapsulation. The compressive strength and bulk density of the NAT-K- or KASH-hybridized cement mortars were tested at 1, 7 and 28 days. The heavy metal encapsulation capacity was also tested using the 28-day cement mortar containing either 5 wt% NAT-K or KASH adsorbed with Cr, Ni and Cd ions. The results showed that 5 wt% of NAT-K could improve early strength of cement mortar and the 28-day specimens with 5-10 wt% of NAT-K replacement had compressive strength similar to that of the normal cement mortar. The NAT-K and KASH encapsulate Cr, Ni and Cd ions in the structures of cement mortar matrices more than 97%. © 2012 Elsevier Ltd. All rights reserved.
Siriwatwechakul W.,Thammasat University |
Siramanont J.,Siam Research and Innovation Co. |
Vichit-Vadakan W.,Siam Research and Innovation Co. |
Vichit-Vadakan W.,American Concrete Institute
American Concrete Institute, ACI Special Publication | Year: 2012
The use of superabsorbent polymers as internal curing agents in high performance concrete has gained much interest in research and slowly gaining interest among industrial producers. Although there have been many publications on the microstructure of internally cured system, little interest has developed in the actual mechanisms of absorption and desorption of superabsorbent polymers in high pH systems and how they are related to the structure of the polymers themselves. Results in the literature indicate that the polymer structure actively interacts with the ions present in the solvent, which results in a strong ion filtration effect. This paper demonstrates that this ion filtration effect is due to electrostatic interaction. The timing and dominance of this effect can heavily influence the effectiveness in internal curing. In particular, concrete containing superabsorbent polymers demonstrate different strength gain behaviors when cured in lime-saturated water.
Daim T.U.,Portland State University |
Daim T.U.,University of Pretoria |
Intarode N.,Siam Research and Innovation Co.
International Journal of Technology, Policy and Management | Year: 2011
This paper demonstrates the use of a technology roadmap to create a holistic picture of the movement in a mature industry. Not only does it also help the cement manufacturers in mature and emerging markets, but also balances between market pull and technology push at a commercialised scale. The roadmap concept can assist any organisation to address three key strategic questions: where the company aims to go, where the status quo of the company and how the company will achieve its strategic intent goals. Thus, in this research, we illustrate the evolution of cement product from present to 2050 through the existing industrial literature, analysing forces, trends, impacts and developing a global cement product roadmap. The roadmap covers a wide range of cement products. Copyright © 2011 Inderscience Enterprises Ltd.
Meier M.R.,TU Munich |
Sarigaphuti M.,Siam Research and Innovation Co. |
Sainamthip P.,Siam Research and Innovation Co. |
Plank J.,TU Munich
Construction and Building Materials | Year: 2015
Early ettringite formation from an industrial CEM I 42.5 N hydrated for 10 s at terrestrial and micro gravity conditions was studied in the presence and absence of a polycarboxylate (PCE) superplasticizer. The cement produced very tiny hexagonal ettringite crystals (l ∼ 180 nm, d ∼ 250 nm). The microgravity resulted in ∼25% more crystals at slightly higher aspect ratio (1.4 versus 0.8 at 1 g). In the presence of PCE, generally larger ettringite crystals (l ∼ 325 nm, d ∼ 225 nm) were formed. Microgravity seems to hinder the growth of ettringite on the lateral faces. © 2015 Elsevier Ltd. All rights reserved.
Thongsanitgarn P.,Chiang Mai University |
Wongkeo W.,Chiang Mai University |
Sinthupinyo S.,Siam Research and Innovation Co. |
Chaipanich A.,Chiang Mai University
Advanced Materials Research | Year: 2012
In this study limestone powders with different particle sizes of 5, 10 and 20 μm were used to replace a part of Portland cement in different replacement levels to produce Portland-limestone cement pastes. The percentages of limestone replacement are 0, 5, 7.5, 10, 12.5, 15 and 20% by weight. The effect of fineness and the amount of limestone powders on compressive strength and setting time are investigated. It has been established that limestone replacement causes reduce the compressive strength due to the dilution effect, but it can reduce energy consumption and CO2 emission in cement manufacturing. The fineness of limestone powder used has influence on the observed compressive strength values. From the standard consistency results, it seems that limestone has no effect on water requirement compared to Portland cement. Moreover, the increase in level of fine particles would require much water. Both initial and final setting times were decreased with an increase in the amount of limestone. Furthermore, at the same level replacement, the cement pastes using 5 μm of limestone show lower setting time than those using 10 and 20 μm, respectively. © (2012) Trans Tech Publications, Switzerland.
Sisomphon K.,Technical University of Delft |
Sisomphon K.,Siam Research and Innovation Co. |
Copuroglu O.,Technical University of Delft |
Koenders E.A.B.,Technical University of Delft
Construction and Building Materials | Year: 2013
This project studies the self-healing potential of strain hardening cementitious composites (SHCC) incorporating calcium-sulfoaluminate based expansive additive (CSA) and crystalline additive (CA). Four mixes, control mix (M1), 10%CSA mix (M2), 1.5%CA mix (M3) and 10%CSA + 1.5%CA mix (M4), were used in the investigation. Pre-cracked specimens were subjected to different exposure conditions; namely, tap water (EC1), regularly refreshed tap water (EC2), wet/dry cycles (EC3) and air exposure (EC4). The recovery of mechanical properties can be obtained, particularly for M2 and M4 mixes. The concentration of carbonate ions in exposed water plays an important role on self-healing process. Calcium carbonate formation on crack mouth is preferable in terms of water tightness; however, this formation decreases the recovery of mechanical properties. The results from chemical analysis showed that the healing products are composed of CaCO3, C-S-H and ettringite. The proportion of healing minerals depends on exposure condition and the type of cementitious materials used. © 2013 Elsevier Ltd. All rights reserved.
Siriwatwechakul W.,Thammasat University |
Siramanont J.,Siam Research and Innovation Co. |
Vichit-Vadakan W.,Siam Research and Innovation Co.
Journal of Materials in Civil Engineering | Year: 2012
Although superabsorbent polymers, especially polyacrylamides, have been successfully used as internal curing agents in concrete for over a decade, the absorption and desorption behaviors, which are key factors in determining the effectiveness of internal curing, are not yet fully understood. Polyacrylamides tend to deprotonate in a high pH environment, allowing superabsorbency of high pH solutions, but their structure is very sensitive to changes in ionic content and concentration of the surrounding solution. This work is aimed at demonstrating how polyacrylamides with very similar chemical compositions can behave differently as they are exposed to different solutions. In parallel, two solutions with the same pH can cause the same polyacrylamide to swell differently. Spontaneous swelling and deswelling behavior in saturated conditions is observed under significant changes in the ion concentration of the surrounding solution. The polyacrylamides used in this work also show strong ion filtration behavior, as observed through analyses of the surrounding pores' solution. © 2012 American Society of Civil Engineers.
Jongvisuttisun P.,Siam Research and Innovation Co. |
Kurtis K.E.,Georgia Institute of Technology
Cement and Concrete Composites | Year: 2015
The availability, relative consistency, and renewability of hardwood pulp fibers have prompted interest in their use in fiber-cement composites, in which they may be used for a variety of purposes. This study clarifies the ability of hardwood pulp to reinforce mortar, its capacity to provide internal curing, and its role as early-age crack-control reinforcement through a coordinated series of restrained shrinkage, free shrinkage, and mechanical testing on mortar samples. It finds that hardwood pulp improves the restrained shrinkage behavior of mortar at an early age. That is, 0.5% and 0.75% (by volume) hardwood pulp-reinforced mortars exhibited a lower rate of stress development and lengthened time-to-cracking by about 1.6 times and 2.3 times, respectively, compared to a companion crack-prone ordinary mortar. The initial crack width also decreased by 88% in 0.75% hardwood pulp-reinforced mortar samples, which suggested an application aimed at assisting self-healing in cement-based materials with an appropriate binder composition. Hardwood pulp successfully provided internal curing to crack-prone mortar and thus reduced autogenous shrinkage. This reduction in shrinkage, together with a combination of increased early tensile capacity, reduced stiffness, and improved post-cracking toughness were identified as the key contributions of hardwood pulp in the improved resistance of mortar to early-age cracking. © 2014 Elsevier Ltd. All rights reserved.