Properties of Seawater Coral Sand Powder Engineered Cementitious Composites after High-Temperature Exposure

doi:10.16552/j.cnki.issn1001-1625.2025.0955

Abstract

Abstract:

To enhance the application reliability of coral resources in marine concrete structures under high-temperature environments， this study investigated the effects of different coral sand powder （CSP） volume replacement ratios （0%， 25%， 50%， and 100%） on the residual compressive strength， spalling behavior， and microstructure of seawater coral sand powder engineered cementitious composites （SCECC） after high-temperature exposure. The test results show that SCECC with a 25% CSP volume replacement ratio maintains good load-bearing capacity and structural integrity below 400 ℃， whereas at a 100% volume replacement ratio， significant strength degradation and delayed spalling occur due to calcium carbonate decomposition and interfacial structure damage. Scanning electron microscopy analysis indicates that an appropriate amount of CSP can optimize the interfacial transition zone structure， while thermal decomposition at high temperatures disrupts the matrix continuity. This study elucidates the high-temperature damage mechanisms and interfacial response characteristics of CSP in SCECC， providing experimental evidence for the design and evaluation of engineered cementitious composites serving in high-temperature marine environments.

Key words: engineered cementitious composites （ECC）, coral sand powder, high-temperature exposure, residual compressive strength, spalling behavior, microstructure

CLC Number:

TU528

HONG Chuanhai, LIANG Ruiqing, LIANG Zhensheng, ZHANG Botao, TANG Xuemei, RUAN Guowei, LIN Jiaxiang. Properties of Seawater Coral Sand Powder Engineered Cementitious Composites after High-Temperature Exposure[J]. BULLETIN OF THE CHINESE CERAMIC SOCIETY, 2026, 45(4): 1151-1159.

Figures/Tables 14

Table 1 Chemical composition of main raw materials

Material	Mass fraction/%
Material	CaO	SiO₂	Al₂O₃	SO₃	Fe₂O₃	MgO	Other
PC	67.81	16.48	3.94	4.55	4.51	1.04	1.67
FA	4.01	54.00	31.20	2.20	4.16	1.01	3.42

Table 2 Physical and mechanical properties of PE fiber

Density/

（g·cm^-3）

Elongation/%

Melting

temperature/℃

Decomposition

temperature/℃

Table 3 Compound concentrations of artificial seawater

Chemical composition	NaCl	MgCl₂·6H₂O	Na₂SO₄	CaCl₂	KCl	NaHCO₃	KBr	H₃BO₃
Concentration/（g·L^-1）	24.53	5.20	4.09	1.16	0.69	0.20	0.10	0.03

Table 4 Groups and mix proportion of SCECC

Group	Mix proportion/（kg·m^-3）
Group	PC	FA	QP	CSP	ASW	HRWR	DF	PE fiber
R-0	600.0	600.0	432.0	0	348.0	3.6	1.8	19.4
R-25	600.0	600.0	324.0	113.0	348.0	3.6	1.8	19.4
R-50	600.0	600.0	216.0	226.0	348.0	3.6	1.8	19.4
R-100	600.0	600.0	0	453.0	348.0	3.6	1.8	19.4

Fig.1 Heating curves for residual compressive strength test

Fig.2 Heating curves for spalling behavior test

Fig.3 Residual compressive strength of SCECC at different temperatures

Fig.4 Strength loss of SCECC at different temperatures

Fig.5 Spalling behavior of specimens after removal from furnace

Fig.6 Spalling behavior of specimens after 14 d of natural exposure

Fig.7 Mass loss of SCECC

Fig.8 Water absorption rate of SCECC

Fig.9 EDS analysis of ITZ between aggregate and matrix in ambient temperature

Fig.10 Micro-morphology of SCECC with different CSP replacement ratios at different temperatures

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