려말선초 혼란기에 불교는 타락하고 활발했던 조영의 분위기는 침체기에 빠져들었다. 그런 가운데 우리나라 사찰건축의 명맥을 유지된 몇 가지 중요한 원인을 가지고 있었다. 첫째, 건물짓는 기술자가 바로 승장 대목 자신들이라는 점과 혼란기를 틈타 엄격함으로부터 어느 정도 자유스럽게 영조할 수 있었다는 점이다. 이러한 인식의 변화는 그대로 건물에 나타나게 된다. 이러한 대표적인 사례가 사찰 전각 측면공포에 대한 등간격배열방식이다. 그 동안 이 문제에 대해 심도갚은 연구가 진행되지 않은 상태에서 서둘러 규정짓는 자세에 문제가 있었다고 본다. 본 연구는 이러한 문제점을 제기하면서 보다 심도있는 연구가 되기를 바라는 마음에서 고찰되었다.

Coal briquette ash is an inorganic and non-combustible material. Although coal briquette ash is mainly composed of SiO2, Al2O3, and is an acceptable raw industrial material (containing Fe2O3, K2O, MgO, CaO, TiO2, and Na2O), it is merely considered waste and is exploited as a building material for concrete admixtures and bricks. Because mullite (3Al2O3 2SiO2), which coal briquette ash contains, is a stable compound with a crystalline structure, it plays essential roles in its fracture strength and bending strength. This study serves the purpose of developing environmentally friendly, economical clay bodies through the use of coal briquette ash as a substitute for kaolin to provide Al2O3 and SiO2. We also investigated the seed effects during sintering process by feeding mullite directly into clay bodies. The results show that in 1,300°C heat, a mixture of 40% coal briquette ash, 40% feldspar/limestone (8 : 2), and 20% clay indicates a fracture strength value of 525 kgf/cm2, an absorption rate of 0.72%, burning shrinkage of 11.5%, and an average bending strength of 0.6 cm, which is superior to other clay bodies. The addition of coral briquette ash in clay bodies promoted mullite formation and grew as mullite acted as a seed. In addition to the developing clay bodies, it can also make an oatmeal-colored glaze to widen the spectrum of its usability. This study will help resolve waste problems, reduce environmental pollution, and raise economic value by using coal briquette ash as a raw material for ceramics. Clay bodies made with coal briquette ash are expected to continuously contribute to the development of the ceramics industry with upcycling effects.