• Magazine of the Korea Concrete Institute
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• v.8 no.3
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• pp.157-165
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• 1996

The purpose of this study is to develop the epoxy-modified mortars and concretes without hardener having a good balance between performance and cost. In this study, the epoxy-modified and concretes without and with the hardener are prepared with various polymer-cement ratios, and tested for the mechanical properties of the epoxy-modified mortars and concretes without and with the hardener. From the test results, the epoxy-modified mortars and concretes without the hardener having an excellent mechanical properties are developed at low polymer-cement ratios of 10 to 20% compared with those of conventional epoxy-modified mortars and concretes with the hardener.

• Cement Symposium
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• no.23
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• pp.156-164
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• 1995

• Cement
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• s.186
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• pp.34-42
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• 2010

• Applied Chemistry for Engineering
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• v.9 no.3
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• pp.336-341
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• 1998

A comparative study on the effects of mean particle diameter and substitutional ratio of II-anhydrite on the fluidity of cement paste has been conducted. Three different mean particle diameters(4, 14 and $35{\mu}m$) and four different substitution ratios(3, 5, 10, 15wt%) have been tested while the dosage of two superplasticizers - naphtalenic(NSF) and polycarboxylic(NT-2) - has been varied from 0 to 2.0wt%. To investigate the effects of those parameters, the variation in fluidity and apparent viscosity of the cement paste has been observed as a function of the elapsed time. The initial fluidity of the cement paste is more affected by the increase in substitution ratio than by the mean particle size of the II-anhydrite. When the substitution ratio of the II-anhydrite is fixed at 10wt%, addition of 1.0wt% NT-2 improves the fluidity of paste cement more than that for NSF. This case has showed the best improvement of the fluidity in the range of parameters investigated. At the addition of 1.0wt% NT-2, apparent viscosity of the cement paste has been noticeably decreased as substitutional ratio of II-anhydrite increases. It was found that it would be more effective to substitute II-anhydrite at a certain ratio to improve the fluidity of the cement paste, in addition to adding NT-2.

• Cement Symposium
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• no.25
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• pp.94-101
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• 1997

• Cement Symposium
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• no.25
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• pp.110-116
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• 1997

• Journal of the Korea Concrete Institute
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• v.21 no.6
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• pp.729-735
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• 2009

In this study, it is experimentally verified a feasibility of the wasted phosphogypsum ($CaSO_4/H_2O$) that is a byproduct from the phosphoric acid process of manufacturing fertilizers can be applied as an admixture in slag cement. For the test, phosphogypsum is modified as dihydrate, hemihydrate, type III anhydrite, and type II anhydrite, and then chemical characteristics and mechanical properties of various slag cements containing above mentioned gypsum materials were analyzed. The test results show that the gypsum made at high temperature has better quality with decrease of water-soluble phosphoric acid ($S-P_2O_5$) which has an effect on the quality of cement. And type II anhydrite shows superior quality in terms of drying shrinkage and the compressive strength of cement paste with hemihydrate at 56 days is higher than other gypsum material.

• Cement
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• s.13
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• pp.61-87
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• 1965

• Cement
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• s.106
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• pp.11-15
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• 1987

• Cement
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• s.12
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• pp.36-46
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• 1965