Yu Zhengyu， Su Yanli， Zhao Hongbo， Zhao Piqi
Shandong Provincial Key Laboratory of Green and Intelligent Building Materials， University of Jinan， Jinan 250022， China
Abstract
Objective Medium- and high-density foamed concrete combines lightweight characteristics with relatively high load-bearing capacity，but achieving simultaneous optimization of strength and shrinkage remains challenging.Its macroscopic performance is also closely related to fresh-state rheology and pore structure.This study investigates the effects of foam content，water-to-binder ratio，and sand-to-binder ratio on the density，compressive strength，water absorption，rheological behavior，pore structure，and autogenous shrinkage of high-strength foamed concrete.Particular attention is given to the mechanism by which the sand-to-binder ratio regulates pore structure and overall performance through slurry rheology， foam encapsulation，particle packing，and skeleton restraint.
Methods Foamed concrete with a target dry density of approximately 1 500 kg/m3 was prepared using P·O 52.5 Portland cement， quartz sand， preformed foam， polycarboxylate superplasticizer， and water. The superplasticizer dosage was fixed at 0.3% of the binder mass.Foam contents of 1%， 2%， and 3%， water-to-binder ratios of 0.20， 0.25， 0.30， and 0.35，and sand-to-binder ratios of 0.8-1.4 were investigated using a single-factor control method. Dry density， compressive strength，water absorption， rheological properties， autogenous shrinkage， and pore structure were measured. The shear stress⁃shear rate curves were fitted using the Bingham model to obtain dynamic yield stress and plastic viscosity. Pore structure was quantified from cross-sectional images using ImageJ.
Results and Discussion Increasing foam content reduced the dry density but also weakened the load-bearing capacity of foamed concrete. When the foam content increased from 1% to 3%， the dry density decreased from 1 558 to 937 kg/m3， while the 28 d compressive strength decreased from 20.30 to 10.16 MPa. This was mainly attributed to the increased pore volume， thinner pore walls， and increased possibility of pore coalescence. The water-to-binder ratio also strongly affected matrix compactness. As the water-to-binder ratio increased from 0.20 to 0.35， the 28 d compressive strength decreased from 24.89 to 14.66 MPa. A lower water-to-binder ratio reduced excess free water and limited the formation of capillary and interconnected pores， thereby improving strength and reducing water absorption.
Conclusion Foam content primarily controls the density and load-bearing capacity of foamed concrete， while a low water-to-binder ratio improves matrix compactness and reduces water absorption. The sand-to-binder ratio is a key parameter linking fresh-state rheology with hardened pore structure and volume stability. An appropriate sand-to-binder ratio improves particle packing and foam stability， refines the pore structure， reduces water transport， and provides skeleton restraint against shrinkage. Excessive sand content， however， weakens paste continuity and increases structural defects. Therefore， the coordinated optimization of foam content， water-to-binder ratio， and sand-to-binder ratio is necessary to balance strength， water resistance， pore stability， and shrinkage control in high-strength foamed concrete.
Keywords： foamed concrete； water-to-binder ratio； sand-to-binder ratio； compressive strength； porosity
Get Citation:Yu Zhengyu， Su Yanli， Zhao Hongbo， et al. Mix proportion optimization and pore structure regulation of high-strength foamed concrete［J］. China Powder Science and Technology， 2026， 32（6）： 1-11.
Received：2026-07-13， Revised： 2026-09-13， Online： 2026-10-08。
Funding： The research was supported by the National Natural Science Foundation of China (Grant No. 52572030) and the Jinan Science and Technology Program (Grant No. 202428053).
DOI：10.13732/j.issn.1008-5548.2026.06.016
CLC No.:TU525.9； TB4
Type Code:A
Serial No.:1008-5548（2026）06-0001-11
