High Temperature Properties of Cement Mortar Using EVA, EVCL Redispersible Polymer Powder and Fly Ash

EVA, EVCL 분말수지와 플라이애시를 혼입한 시멘트 모르타르의 고온특성

Abstract

3D printing technology of construction field can be divided into structural materials, interior and exterior finishing materials, and is mainly done by extruding and adapting. Particularly when it is applied as an exterior materials, it is mainly applied to an unstructured exterior materials and high accuracy is required. The exterior materials can be used as a cement composite materials, it is suitable also for a additive type manufacturing, and the role of a redispersible polymer powder is important. But, high temperatures, redispersible polymer cement base material beget dehydration and micro crack of cement matrix. In this research, we developed a EVA, EVCL redispersible polymer cement base material applicable as a 3D printing exterior materials, confirmed density and strength characteristics for application as an exterior materials, a flame retardancy test for improving the fire resistance of buildings and confirmed its possibility. From the test result, developed EVCL redispersible polymer cement mortar showed good stability in high temperatures. These high temperature stability is caused by the ethylene-vinyl chloride binding. Thus, this result indicates that it is possible to fire resistant 3D printing interior and exterior finishing materials.

건축물에서의 3D 프린팅은 구조재 및 비구조재로의 적용으로 구분되며, 비구조재는 내 외장 패널이나 조형물로의 적용 등이 주를 이룬다. 연속적으로 적층하여 제조하는 3D 프린팅 방식은 시멘트 모르타르의 경화속도나 특성을 개질하며 이를 위한 재료의 혼입과 경화속도나 시공성, 접착성의 개선을 위한 시멘트 혼화용 폴리머의 사용이 필수적이다. 본 연구는 적층방식 3D 프린팅 적용을 위해 시멘트, 플라이애시, EVA 및 EVCL 분말수지의 혼입률을 달리하여 고온에서의 특성을 검토하였고 혼입에 따른 유효성 여부를 확인하였다. 실험결과, EVA 및 EVCL 분말수지에 혼입에 따라 시멘트 모르타르는 연행된 공기에 의해 특성이 개질되었고 EVA보다는 EVCL을 혼입한 시험체가 고온에서 유리하였다.

Fig. 1. Diameter of raw materials

Fig. 2. Heating condition of polymer cement mortar

Fig. 3. Density vs. temperature of EVA, EVCL polymer cement mortars

Fig. 4. Compressive strength vs. temperature of EVA, EVCL polymer cement mortars

Fig. 5. Relative compressive strength vs. temperature of EVA, EVCL polymer cement mortars

Fig. 6. Cumulative porosity vs. temperature of EVA, EVCL polymer cement mortars

Fig. 7. Heat release rate of EVA, EVCL polymer cement mortars

Fig. 8. Total heat release rate of EVA, EVCL polymer cement mortars

Table 1. High temperature property in cement based materials and EVA, EVCL

Table 2. Raw materials of polymer cement mortar

Table 3. Mix proportions of EVA, EVCL polymer cement mortars

Table 4. The results of cone calorimeter test