• International Journal of Highway Engineering
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• v.18 no.1
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• pp.43-55
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• 2016

PURPOSES : This study aims to develop a repair material that can enhance pavement performance, inducing rapid traffic opening through early strength development and fast setting time by utilizing MgO-based patching materials for repairing road pavements. METHODS : To consider the applicability of MgO-based patching materials for repairing domestic road pavements, first, strength development and setting time of the materials were evaluated, based on MgO to $KH_2PO_4$ ratio, water to binder ratio, and addition ratio of retarder (Borax), by which the optimal mixture ratio of the developed material was obtained. To validate the performance of the developed material as a repair material, the strength(compressive strength and bonding strength) and durability (freezing, thawing, and chloride ion penetration resistance) was checked through testing, and its applicability was evaluated. RESULTS : The results showed that when an MgO-based patching material was used, the condensation time was reduced by 80%, and the compressive strength was enhanced by approximately 300%, as compared to existing cement-based repair materials. In addition, it was observed that the strength (compressive strength and bonding strength) and durability (freezing and thawing, and chloride ion penetration resistance) showed an excellent performance that satisfied the regulations. CONCLUSIONS : The results imply that an emergent repair/restoration could be covered by a rapid-hardening cement to meet the traffic limitation (i.e. the traffic restriction is only several hours for repair treatment). Furthermore, MgO-based patching materials can improve bonding strength and durability compared to existing repair materials.

• Journal of the Korean Ceramic Society
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• v.41 no.9
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• pp.715-721
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• 2004

Hydroxyapatite (HAp)/Gelatin (GEL) homogeneous composites of four different composition ratio were prepared by the co-precipitation process with synthetic HAp and GEL as a binder, HAP/GEL composites were molding by cold isostatic pressing and were sintering by various condition in air. Crystallinity and structure of sintered HAp/GEL composites were investigated by XRD and FTIR. Also, the compressive strength and the fracture surface of sintered specimens were measured by UTM and SEM. HAp/GEL composites showed a phase transformation to partially ${\alpha}$, ${\beta}$-tricalcium phosphate at the sintered condition of 1200$^{\circ}C$ for 3 h. The porosity of sintered body was in the range of 1.2-30.2％. The compressive strength of the sintered specimens was in the range of 16.2-60.1㎫, and its strength of sintered HAp/GEL comosites was higher than expected when the porosity was considered.

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.566-571
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• 2003

Hydroxyapatite (HAp)/Polyacrylic Acid(PAA) homogeneous composites of four different composition ratio were preparation by co-precipitation process with synthetic HAp and PAA as a binder. HAP/PAA composites were molding by cold isostatic pressing and were sintering by various condition in air. Crystallinity and structure of sintered HAp/PAA composites were investigated by XRD and FT-IR. Also, the compressive strength and the fracture surface of sintered specimens were measured by UTM and SEM. HAp/PAA composites were showed phase transformation of partially ${\alpha}$, ${\beta}$-tricalcium phosphate at sintering condition of 1200$^{\circ}C$ and 3 h. The pore size and porosity of sintered body were showed the range of 0.2∼3.0 $\mu\textrm{m}$ and 0.49∼13.43%, respectively. The compressive strength of sintered specimens were appeared the range of 36.6∼58.2 MPa. From these results, the sintered HAp/PAA comosites can be accounted for the microporous HAp having a good compressive strength due to homogeneous pore morphology.