• Cement
• /
• s.38
• /
• pp.22-27
• /
• 1970

• Cement
• /
• s.108
• /
• pp.30-33
• /
• 1987

• Cement Symposium
• /
• no.31
• /
• pp.106-114
• /
• 2004

• Journal of the Korea Institute of Building Construction
• /
• v.13 no.3
• /
• pp.227-234
• /
• 2013

In this research, early strength development performance of early strength improvement type ordinary cement which is economically feasible early strength cement(Type III), improved early strength ordinary cement(Type I), was estimated to derive minimum curing temperature and proper water to cement ratio according to cement for early strength development through examination of fresh concrete properties and compressive strength according to water to cement ratio curing $10^{\circ}C$, $15^{\circ}C$ and $20^{\circ}C$ to suggest fundamental data for practical use of early strength concrete.

• Magazine of the Korean Society of Agricultural Engineers
• /
• v.14 no.3
• /
• pp.2677-2684
• /
• 1972

This study was carried out to search for an effect on strengths of a pozzolan and a high-early strength cements due to accelerating the initial setting and a rate of strength development at early age, and to obtain the effects applicable for structural construction works safety in the cold winter weather. The results of the study were as follows: 1. The early strength of high-early strength cement was higher than an ordinary portland cement(Type I). 2. High-early strength cement had a characteristic suitable for construction works in the cold weather due to the rate of acceleration of the eary strength. 3. When using pozzolan cements, a weight proportion should be considered in mix design since the pozzolan cement has a lower specific gravity than other portland cements. 4. It was desirable for the pozzolan cement to shorten the storage period since particles of the pozzolan cement was so fine that it was likely to weathering.

• Journal of the Korea institute for structural maintenance and inspection
• /
• v.18 no.1
• /
• pp.84-92
• /
• 2014

The purpose of study is to analyze mechanism with early high portland cement and hardening accelerator. As the result, it was concluded that hardening accelerator makes accelerates appearance of $Ca(OH)_2$ through experiment using TG-DTA when it hydrates with cement. On the result of compressive strength, as increasing the amount of hardening accelerator used, early compressive strength was improved. Also, as a result of hydration heat, hardening accelerator accelerates hydration of $C_3S$ that is cement's component. On the result of XRD's analyzation, hydration product for each age could be check and it was shown that as increasing the amount of hardening accelerator used, peak point of hydration product was recorded high. As the result of SEM, appearance of C-S-H was shown as the amount of $Ca(OH)_2$'s appearance and each age according to additive contents of hardening accelerator. Therefore hardening accelerator used on this study is effective on getting early compressive strength.

• Journal of the Korea Institute of Building Construction
• /
• v.13 no.4
• /
• pp.407-415
• /
• 2013

The purpose of this research is to verify the performance of hardening accelerator in cement paste through mechanical performance evaluation and micro structure analysis on hardening accelerator for development of super high early strength concrete. The research results showed that hardening accelerator produced $Ca(OH)_2$ when hydrated with cement, enhancing the degree of saturation of Ca ion by using differential thermal analysis. Moreover, porosity was reduced rapidly as capillary pores were filled by hydration products of $C_3S$. According to the experiment using hydration measurement testing, when 1% and 3% of accelerator were mixed, hydration rate increased toward the second peak point compared to high early strength cement, before the first peak point disappeared. It turned out that adding accelerator accelerated the hydration rate of cement, especially $C_3S$. The shape of C-S-H is shown depending on the amounts of accelerator added and the production and age of $Ca(OH)_2$ by using SEM to observes hydration products. Therefore, it's evident that hardening accelerator used in this research increases amounts of $Ca(OH)_2$ and accelerates $C_3S$, it is effective for the strength development on early age.

• Cement Symposium
• /
• no.18
• /
• pp.33-39
• /
• 1990

• Cement Symposium
• /
• no.28
• /
• pp.63-66
• /
• 2001

• KSCE Journal of Civil and Environmental Engineering Research
• /
• v.29 no.1A
• /
• pp.95-100
• /
• 2009

This study proposed mix proportions of early strength pavement concrete for large size area using calcium nitrate. Therefore, we used type III cement with calcium nitrate. Laboratory tests conducted to air content, slump loss test, setting time test, compressive strength test and flexural strength test. Our early strength pavement concrete mixture proportion proposed in this study for large size area attained the required compressive strength of 21 MPa and a flexural strength of 3.8 MPa, which allowed it to be opened to traffic within 8 hours. Based on test results, we suggested optimum mix proportions of early strength pavement concrete for large size area using calcium nitrate.