Preparation and water absorption evaluation of hydrophobic aeolian sand mortar with wet-process modified fly ash using an aluminate ester coupling agent
LI Yugen
CHEN Hongyu
LU Rui
YU Zhao
MENG Xiangzhen
WANG Hairen
Abstract：The hydrophobic aeolian sand mortar was prepared using aeolian sand as fine aggregate and fly ash modified by Aluminate Ester Coupling Agent(AGA)via a wet process,where the modified fly ash replaced 40%of cement by mass.Its water absorption characteristics were evaluated,and the modification mechanism was analyzed by means of SEM,XRD,and FT-IR.The results show that the water contact angle of the modified fly ash first increases and then decreases with increasing AGA content.Under the conditions of 5%AGA content and 1 h of stirring,the fly ash achieves super-hydrophobicity.The mortar prepared with this fly ash shows a surface water contact angle of 140.35°,and its cumulative water absorption is reduced by 73%compared with the control group.The physical modification mechanism of AGA on fly ash is attributed to the adsorption of long-chain alkyl groups,which reduces the surface energy and alters the surface microstructure.The chemical mechanism involves the esterification reaction between alkoxy groups in AGA and hydroxyl groups(such as Si—OH and Al—OH)on the fly ash surface,forming Si—O—Al/Al—O—Al covalent bonds and thus achieving molecular anchoring.
Keywords：wet-modified fly ashhydrophobic aeolian sand mortarabsorption performance evaluationmodification mechanism
Publication Date：2025-12-25
Online Publishing Date：2026-01-13(First online date of this platform, not the publication date of the document)
Pages：5( 118-122 )