Preparation and Performance Characterization of Coal Gangue-Fly Ash Porous Aggregate
WANG Xiaoxiao
GUAN Xueyi
JING Lei
LIU Shuguang
YAN Changwang
Abstract：Porous aggregates were prepared by coal gangue and fly ash.The evolution of the phase composition,microscopic structure and pore structure of the aggregates during the sintering process were analyzed by X-ray diffraction,scanning electron microscope and mercury intrusion porosimeter.The results show that under the process conditions of preheating temperature of 500℃,preheating time of 20 min,sintering temperature of 1 000℃,and sintering time of 10 min,the coal gangue-fly ash porous aggregates prepared have a cylinder pressure strength of 2.50 MPa and a thermal conductivity of 0.141 6 W/(m·K).When the sintering temperature increases form 1 000℃to 1 200℃,mullite accumulates to form pores with a pore diameter d<1 000 nm,and the medium pores and large pores are covered by a liquid phase with an average thickness of approximately 0.466 µm.The volume fraction of large pores decreases by 34.49%,and the cylinder pressure strength increases.The high thermal conductivity of mullite and the decrease in the average pore diameter lead to an increase in the thermal conductivity of the porous aggregates.The carbon total emission of the porous aggregates in 1 m3 concrete is 140.200 kg CO₂ eq.,which is 56.2%and 56.3%lower than that of Stalite aggregates and fly ash lightweight aggregates respectively,indicating that it has greater green potential.
Keywords：coal ganguefly ashporous aggregatecylindrical compressive strengththermal conductivitypore structure
Publication Date：2025-08-30
Online Publishing Date：2025-09-05(First online date of this platform, not the publication date of the document)
Pages：8( 782-789 )