Title: High-Volume Fly Ash Engineered Cementitious Composite for Underground and Hydraulic Engineering

Author(s): Xiaoqin Li, Li Zhang, Wenlu Wen, Shihua Li, and Xu Zhou

Publication: Materials Journal

Volume: 121

Issue: 1

Appears on pages(s): 55-66

Keywords: engineered cementitious composite (ECC); high-volume fly ash; impermeability; low drying shrinkage; toughness; workability

DOI: 10.14359/51739200

Date: 1/1/2024

Abstract:
Engineered cementitious composites (ECCs) have excellent toughness and crack-control abilities compared to other cement-based materials, which can be used in underground and hydraulic engineering. Nevertheless, excellent impermeability and workability and low drying shrinkage are also required. Two groups of ECC mixture proportions with high fly ash-cement (FA/c) and watercement ratios (w/c) were chosen as baselines, and silica fume (SF) and a shrinkage-reducing agent (SRA) were introduced to improve the impermeability, workability, and mechanical behaviors. The workability laboratory evaluation indexes of ECC were also discussed. ECC mixture proportions with excellent workability (pumpability and sprayability), high toughness (ultimate tensile strain ɛtp over 3.5%), good impermeability (permeability coefficient K = 1.713 × 10–11 m/s), and low drying shrinkage (drying shrinkage strain ɛst = 603.6 × 10–6) were finally obtained. Then, flexural and shear tests were carried out for the material flexural/ shear strength and toughness evaluations, giving the characteristic material properties for the final ECC mixture proportions.