Mechanical Properties and Microstructure of Hydraulic Concrete Based on Double-Layer Placed-Fill Process
DONG Haowei
WANG Hailong
ZHANG Wenyan
LI Qingfu
ZHANG Xinyu
Abstract：A double-layer placed-fill method was utilized to introduce aggregates in two layers during the concrete pouring process,with the aim of optimizing the aggregate skeleton structure of pumice lightweight aggregate concrete.This method improved the concrete strength and established a quantitative evaluation system for the particle size range and placed-fill rate of the aggregates.The results show that when the maximum particle sizes of the aggregates are 19 mm and 31.5 mm,and the placed-fill rates are 10%and 20%,the compressive strength of the concrete increases by 16.45%and 8.98%compared to the control group,respectively,and the splitting tensile strength also improves concurrently.The aggregates optimized the microstructure of the matrix.As the throwing-in rate increases,the number of harmful pores decreases,and the width of interfacial microcracks narrow.Dimensionless fitting analysis of the stress-strain curve shows that the variance reaches up to 99%,indicating a good fitting accuracy.Furthermore,the established toughness analysis system indicates that when the particle size range of the aggregates is 4.75-19 mm and the placed-fill rate is 20%,the toughness index increases by 51.9%compared to the control group,while the brittleness index decreases by 47.2%.The aggregate concrete achieves a brittle-to-tough transition.This research provides a process optimization scheme and theoretical support for the engineering application of lightweight aggregate concrete.
Keywords：double-layer placed-fill methodpumice hydraulic concretemechanical propertypore characteristicsdimensionless nonlinear fitting
Publication Date：2025-12-30
Online Publishing Date：2026-01-08(First online date of this platform, not the publication date of the document)
Pages：9( 1226-1234 )