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Econ. Environ. Geol. 2022; 55(6): 571-582

Published online December 31, 2022

https://doi.org/10.9719/EEG.2022.55.6.571

© THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY

Archaeometric Characterization of Raw Materials and Tempers of Bricks Used in the Brick Tombs during Ungjin Period of Baekje

Sungyoon Jang*, Hong Ju Jin

Conservation Science Division, National Research Institute of Cultural Heritage, Daejeon 34122, Korea

Correspondence to : *Corresponding author : fkite@korea.kr

Received: October 13, 2022; Revised: November 29, 2022; Accepted: November 30, 2022

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

In this study, the raw material and tempers of bricks used in three brick tombs built in Gongju, during the Ungjin period of Baekje were investigated. The royal tomb of King Muryeong, the 6th tomb in the royal tombs, and Kyochonri brick tomb remained in Gongju and the bricks of each site had different shape and physical properties despite their similarity in raw materials. As the results of the mineralogical and microstructural analysis, the bricks of the royal tombs were made of refined raw materials, and were infrequently added crushed bricks(grogs) as a tempering material. On the other hand, thick and elongated pores of bricks from the Kyochonri brick tomb were frequently found, and the remains of plant carbonization are observed in their microstructures. Since the pores are mainly distributed in a thickness of 0.3 to 1 mm, it is estimated that bricks were produced by adding a certain size of the plant to refined soil, and grogs also were added as a tempering material. In particular, it was found that adding plants and grogs in raw materials of bricks caused thick pores or cracks in the internal structure. Since the bricks of the Kyochonri brick tomb have internal cracks and low firing temperature, the ultrasonic velocity of the bricks was lower than that of the royal tomb bricks. It means that the mechanical strength of these bricks were relatively low. Accordingly, it is estimated that the tempering materials, firing temperature, and internal structures of bricks can affect durability of the brick, and it can be thought as a difference in the manufacturing technology of brick making.

Keywords brick, brick tomb, tempering material, grog, X-ray computed tomography

백제 웅진기 벽돌무덤에 사용된 벽돌의 재료와 첨가물 특성 분석

장성윤* · 진홍주

국립문화재연구원 보존과학연구실

요 약

이 연구에서는 백제 웅진기 공주에 축조된 벽돌무덤 3기에 사용된 벽돌의 재료와 첨가물 특성을 분석하였다. 공주에는 무령왕릉, 왕릉원 6호분, 교촌리 벽돌무덤이 남아있는데, 각 고분을 구성하는 벽돌의 태토는 유사한 재료적 특성을 가지고 있지만 형태와 물리적 특성이 다르게 나타났다. 광물학적 특성 및 미세구조 분석 결과, 무령왕릉과 왕릉원 벽돌은 정제된 토양으로 제작되었고, 벽돌 분쇄물이 첨가물로 드물게 사용되었다. 반면 교촌리 벽돌무덤 벽돌에서는 길고 두꺼운 흑색 기공의 빈도가 높았고 미세조직 관찰결과에서 탄소가 농집된 식물탄화물과 잔존물이 확인되었다. 또한 기공은 주로 0.3~1mm 두께로 분포하고 있어 일정크기의 식물을 정제된 토양에 첨가하여 제작한 것으로 판단되며, 이와 함께 벽돌 분쇄물도 비짐으로 첨가하였다. 특히 식물과 벽돌 분쇄물의 첨가는 내부구조에 두꺼운 기공을 형성하거나 균열을 발생시키는 것으로 나타났다. 교촌리 벽돌무덤 시료는 내부 균열이 많고 소성온도도 낮아 초음파 속도가 왕릉원 시료에 비해 낮게 나타났고 물성이 낮은 것으로 확인되었다. 이에 따라 벽돌의 첨가물과 소성온도, 내부구조 등은 벽돌의 내구성에 영향을 미칠 수 있는 것으로 생각되며, 이는 벽돌 제작 기술의 차이로 볼 수 있다.

주요어 벽돌, 벽돌무덤, 첨가물, 벽돌 분쇄물, X-선 단층촬영

Article

Research Paper

Econ. Environ. Geol. 2022; 55(6): 571-582

Published online December 31, 2022 https://doi.org/10.9719/EEG.2022.55.6.571

Copyright © THE KOREAN SOCIETY OF ECONOMIC AND ENVIRONMENTAL GEOLOGY.

Archaeometric Characterization of Raw Materials and Tempers of Bricks Used in the Brick Tombs during Ungjin Period of Baekje

Sungyoon Jang*, Hong Ju Jin

Conservation Science Division, National Research Institute of Cultural Heritage, Daejeon 34122, Korea

Correspondence to:*Corresponding author : fkite@korea.kr

Received: October 13, 2022; Revised: November 29, 2022; Accepted: November 30, 2022

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

In this study, the raw material and tempers of bricks used in three brick tombs built in Gongju, during the Ungjin period of Baekje were investigated. The royal tomb of King Muryeong, the 6th tomb in the royal tombs, and Kyochonri brick tomb remained in Gongju and the bricks of each site had different shape and physical properties despite their similarity in raw materials. As the results of the mineralogical and microstructural analysis, the bricks of the royal tombs were made of refined raw materials, and were infrequently added crushed bricks(grogs) as a tempering material. On the other hand, thick and elongated pores of bricks from the Kyochonri brick tomb were frequently found, and the remains of plant carbonization are observed in their microstructures. Since the pores are mainly distributed in a thickness of 0.3 to 1 mm, it is estimated that bricks were produced by adding a certain size of the plant to refined soil, and grogs also were added as a tempering material. In particular, it was found that adding plants and grogs in raw materials of bricks caused thick pores or cracks in the internal structure. Since the bricks of the Kyochonri brick tomb have internal cracks and low firing temperature, the ultrasonic velocity of the bricks was lower than that of the royal tomb bricks. It means that the mechanical strength of these bricks were relatively low. Accordingly, it is estimated that the tempering materials, firing temperature, and internal structures of bricks can affect durability of the brick, and it can be thought as a difference in the manufacturing technology of brick making.

Keywords brick, brick tomb, tempering material, grog, X-ray computed tomography

백제 웅진기 벽돌무덤에 사용된 벽돌의 재료와 첨가물 특성 분석

장성윤* · 진홍주

국립문화재연구원 보존과학연구실

Received: October 13, 2022; Revised: November 29, 2022; Accepted: November 30, 2022

요 약

이 연구에서는 백제 웅진기 공주에 축조된 벽돌무덤 3기에 사용된 벽돌의 재료와 첨가물 특성을 분석하였다. 공주에는 무령왕릉, 왕릉원 6호분, 교촌리 벽돌무덤이 남아있는데, 각 고분을 구성하는 벽돌의 태토는 유사한 재료적 특성을 가지고 있지만 형태와 물리적 특성이 다르게 나타났다. 광물학적 특성 및 미세구조 분석 결과, 무령왕릉과 왕릉원 벽돌은 정제된 토양으로 제작되었고, 벽돌 분쇄물이 첨가물로 드물게 사용되었다. 반면 교촌리 벽돌무덤 벽돌에서는 길고 두꺼운 흑색 기공의 빈도가 높았고 미세조직 관찰결과에서 탄소가 농집된 식물탄화물과 잔존물이 확인되었다. 또한 기공은 주로 0.3~1mm 두께로 분포하고 있어 일정크기의 식물을 정제된 토양에 첨가하여 제작한 것으로 판단되며, 이와 함께 벽돌 분쇄물도 비짐으로 첨가하였다. 특히 식물과 벽돌 분쇄물의 첨가는 내부구조에 두꺼운 기공을 형성하거나 균열을 발생시키는 것으로 나타났다. 교촌리 벽돌무덤 시료는 내부 균열이 많고 소성온도도 낮아 초음파 속도가 왕릉원 시료에 비해 낮게 나타났고 물성이 낮은 것으로 확인되었다. 이에 따라 벽돌의 첨가물과 소성온도, 내부구조 등은 벽돌의 내구성에 영향을 미칠 수 있는 것으로 생각되며, 이는 벽돌 제작 기술의 차이로 볼 수 있다.

주요어 벽돌, 벽돌무덤, 첨가물, 벽돌 분쇄물, X-선 단층촬영

    Fig 1.

    Figure 1.Photographs of brick samples showing the carbonized plant temper (510-11, S1, S6, S7), elongated pores (S2, S3) and blackish minerals (726-11).
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 2.

    Figure 2.3-dimensional pore detection of bricks by X-ray CT showing colored shapes and morphologies of pores.
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 3.

    Figure 3.Abundance and distribution of maximum diameters of pores detected in X-ray CT of brick samples.
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 4.

    Figure 4.Microphotographs of thin section of brick samples showing grogs (724-1, 726-9, S6) and elongated pores caused by plant tempers (513-3, S3, S14).
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 5.

    Figure 5.SEM microphotographs of brick samples, indicating elongated pore (S1), amorphous materials by plant carbonization (S2, S7) and various type of grogs (S6, S8).
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 6.

    Figure 6.SEM mapping of plant residues and grog found in Kyochonri brick samples.
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 7.

    Figure 7.Comparison of elemental concentration of bricks from the royal tombs and Kyochonri brick tomb.
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Fig 8.

    Figure 8.Ultrasonic velocity of brick samples, indicated that Kyochonri brick samples had relatively low ultrasonic velocity.
    Economic and Environmental Geology 2022; 55: 571-582https://doi.org/10.9719/EEG.2022.55.6.571

    Table 1 . List of brick samples in this study.

    SitesSampleShape/Pattern*SitesSampleShape/Pattern*
    Royal tomb of King Muryeong724-1Rectangle(NP)Found around the royal tomb510-41Rectangle(NP)
    724-2Rectangle(L)511-28Rectangle(NP)
    726-1Rectangle(LF)512-2Trapezoidal(LF)
    726-2Trapezoidal(LF)513-3Rectangle(L)
    726-3Trapezoidal(LF)Kyochonri brick tombS1Square(NP)
    726-4Rectangle(LF)S2Square(NP)
    726-5Rectangle(LF)S3Square(NP)
    726-6Rectangle(LF)S4Square(NP)
    726-7Rectangle(LF)S5Square(NP)
    726-8Rectangle(LF)S6Square(NP)
    726-9Rectangle(LF)S7Rectangle with trapezoidal side(NP)
    726-10Rectangle(LF)S8
    726-11Rectangle(LF)S9Rectangle(NP)
    Royal tomb(6th)107-1Rectangle(LF)S10Rectangle(NP)
    Found around the royal tomb510-11Rectangle(NP)S11Rectangle(NP)
    510-22Rectangle(NP)S12Rectangle(NP)
    510-23Rectangle(NP)S13Rectangle(NP)
    510-31Rectangle(NP)S14Rectangle(NP)

    *NP: no pattern, L: letter, LF: lotus-flower pattern.

    † Gongju National Museum (2007); ‡ Jang and Jin (2021).


    Table 2 . Chemical compositions of the clay matrix and grogs of Kyochonri samples presented in Fig. 5 by SEM-EDS.

    SampleOxide%SiO2Al2O3Fe2O3MnOMgOCaONa2OK2OTiO2P2O5
    S6-①Grogmean*58.8019.6317.980.020.690.370.181.570.640.12
    st.dv.1.290.960.830.030.040.010.100.160.110.04
    Matrixmean68.8821.534.880.000.590.610.212.320.980.00
    st.dv.0.720.430.260.000.030.020.020.210.070.00
    S6-②Grogmean69.9117.139.390.000.610.320.161.700.750.04
    st.dv.1.680.791.050.000.080.010.050.160.020.03
    Matrixmean68.1721.585.270.050.680.640.262.420.930.00
    st.dv.1.701.170.060.030.010.040.060.330.180.00
    S8Grogmean52.7427.7815.360.000.720.480.171.900.740.11
    st.dv.2.260.671.840.000.020.040.010.580.120.10
    Matrixmean70.6020.664.770.030.680.290.241.870.860.00
    st.dv.1.881.190.450.010.020.050.110.070.170.00

    * 3 times average.


    KSEEG
    Apr 30, 2024 Vol.57 No.2, pp. 107~280

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