• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.909-916
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• 2013

Concrete containing lightly burnt MgO has long term expansibility. It also could compensate for the thermal shrinkage of mass concrete, because the hydration of MgO proceeds at a slow pace to long-term age. Thus, lightly burnt MgO has been applied to the construction of mass concrete such as dams. Recently, the expansion characteristics of MgO concrete with fly ash that could be applied to mass concrete for the reduction of hydration heat have been studied and however, limited studies on its durability. This study investigates the long-term durability characteristics of fly ash concrete with lightly burnt MgO. The durability tests on carbonation, freezing-thawing, diffusion of chloride, and resistance to sulfate attack were carried out for MgO concrete with curing for 360 days in submerged condition with different temperature of 20 and $50^{\circ}C$. The results reveal that MgO concrete shows a greater resistance of carbonation, diffusion of chloride, and resistance to sulfate attack. On the other hand the resistance of freezing-thawing was little influenced by MgO powder.

• Korean journal of food and cookery science
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• v.33 no.2
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• pp.209-217
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• 2017

Purpose: The aim of this study was to compare the cooking properties of Bodeurami and Ilmi to promote consumption of rice. Methods: The properties of Bodeurami and Ilmi such as proximate composition, Hunter's color value, water absorption rate, and cooking properties as well as Hunter's color value, texture properties, and sensory evaluation of cooked rice were analyzed. Results: Crude protein, crude fat, and crude ash contents of Bodeurami and Ilmi were higher in brown rice than in white rice. Regardless of rice cultivars, L-value was lower, whereas a and b-values were higher in brown rice than in white rice. The water absorption rate of rice grains was higher in white rice than in brown rice and increased rapidly to 75 min for white rice and 4 hr for brown rice. Cooking properties, water absorption, and expansibility of white rice were higher than those of brown rice, and there were significant differences between Bodeurami and Ilmi. Immediately after cooking and after storage at warm ($70^{\circ}C$) and room temperatures ($25^{\circ}C$), hardness of cooked rice increased after storage, but was not significantly different between Bodeurami white rice and Ilmi brown rice. The sensory evaluation shows that Bodeurami brown rice scored the highest for taste, texture and overall preference. Conclusion: Thus, the results of this study shows that Bodeurami brown rice is characterized by high cooking quality without any mixed white rice, and Bodeurami white rice could be used for the rice processing industry as well as cooked rice.

• Journal of the Korea institute for structural maintenance and inspection
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• v.13 no.1 s.53
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• pp.78-87
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• 2009

When the steel slag is utilized to the concrete as the alternative fine aggregate, its use is limited as the concrete aggregate because of expansibility caused by much quantity of free CaO. So, this study is intended to examine the characteristics of the concrete which uses the rapidly cooled steel slag whose content of free CaO is sharply reduced by rapidly cooling the steel slag as the fine aggregate. Accordingly, by comparing and considering the results of the concrete slump loss test with the different substitution ratio and fine aggregate ratio of rapidly cooled steel slag, hydration by XRD and SEM analysis, compressive test by age, a length variation test and rapid chloride ion penetration test, the rapidly cooled steel slag's proper substitution ratio and the fine aggregate ratio was derived.

• Food Science and Preservation
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• v.16 no.6
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• pp.830-837
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• 2009

A total of 24 processed barley samples produced in Korea, 9 split and 15 pressed, were analyzed for protein, $\beta$-glucan, and amylose content whiteness cooking characteristics (water absorption and expansibility) and pasting properties, with respect to the areas in which they were grown. Split and pressed barley products from Japan were compared. Both forms of barley products had similar contents of protein and $\beta$-glucan. Whiteness was higher in pressed barley than in split barley. Split barley produced in Korea had a higher water absorption (342-436%) and expansibility (449-608%) than did pressed barley. Japanese processed barley products were much lower in protein (4.4-6.6%, w/w) and showed a higher whiteness grade than did Korean products. Whiteness of pressed barley ranged from 57.2-68.3 and was higher than that of split barley, but split barley product showed better cooking characteristics than did pressed barley. Japanese products were similar to Korean materials in this respect. A negative correlation was observed between protein content in and whiteness of processed barley products (r=-0.5112, p<0.01). Waxy barley products had a lower pasting temperature, and showed higher breakdown and lower setback than did non-waxy barley products. The pasting properties of Japanese products were different from those of Korean materials. The pasting temperatures of Japanese split and pressed barley were lower, and the setback much higher, than seen with Korean products. The results show that both splitting and pressing efficiently improve the cooking characteristics of barley. The processing of waxy barley was particularly effective.

• Food Science and Preservation
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• v.19 no.1
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• pp.81-86
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• 2012

The objective of this study was to investigate the cooking properties of seven different rice cultivars (Dasan, Keunseom, Goami, Baekjinju, Seolgaeng, Hangangchal, and Heukseol). For the Hunter's color values, the L value was highest in the Seolgaeng cultivar, the a value was highest in the Heukseol cultivar, and the b value was highest in the Hangangchal cultivar. For the water absorption rate, that of the Heukseol cultivar was 80 min up to the saturation point, those of the Dasan and Goami cultivars were 50 min, those of the Baekjinju and Keunseom cultivars were 30 min, and that of the Seolgaeng cultivar was 10 min. The water absorption was highest in the Keunseom cultivar (351.38%). The expansibility and soluble-solid contents were 226.97-551.08 and 5.56-21.05%, respectively. The hardness of the cooked rice was highest in the Heukseol cultivar (24.30 kg); conversely, the Hangangchal cultivar had the lowest value (7.49 kg). Goami was a hard cooked rice, except for the Heukseol cultivar. In the sensory evaluation of the cooked rice, the taste, texture, and overall preference were highest in the Baekjinju cultivar, the color was highest in the Seolgaeng cultivar, the flavor was highest in the Heukseol cultivar, and the appearance was highest in the Hangangchal cultivar. The Dasan and Keunseom cultivars yielded the lowest values in the sensory evaluation, except for texture.

• Journal of the Korea Institute of Building Construction
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• v.15 no.4
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• pp.359-365
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• 2015

Floor mortar experiences dry shrinkage by temperature and humidity difference of internal matrix with material type. Also, since floor mortar is influenced by environmental conditions during placing and curing period, cracks are likely to be occurred. In this study, it was evaluated the hardening and dry shrinkage properties of non-sintered binder based floor mortar utilizing alpha-hemihydrate gypsum which has expansibility in order to prevent crack of the floor mortar. It was applied to the construction site, and examined the effects of external environmental conditions on shrinkage deformation and cracking. Different types of slag accelerated initial and final setting in comparison with cement mortar and its compressive strength was satisfied standard compressive strength for floor mortar. Also shrinkage deformation behavior after the initial expansion exhibited a similar tendency with the cement mortar. From the field application result, no crack was found from slag mortar, and it is determined that the slag mortar has better dimensional stability than cement mortar caused by external environment conditions.