Preparation and Properties of Engineered Cementitious Composites Incorporating a High Volume of Fly Ash

Abstract

As a type of fiber-reinforced composite, engineered cementitious composite (ECC) has the characteristics of multi-cracking and strain-hardening. In this study, domestic materials were used to prepare ECC incorporating a high volume of fly ash. The effect of fly ash on the microscopic and macroscopic performance was studied, and the relationship between the microscopic structure and macroscopic performance was also analyzed. The microscopic pore structure was analyzed by mercury intrusion porosimetry (MIP) with the aim of improving understanding of the variability in ductility. The results obtained show that mesopores and macropores (pores with a diameter greater than 20 nm) have a great influence on the fracture toughness and strength of the matrix, while micropores (diameter less than 20 nm) had no obvious effect on the fracture toughness and strength of the matrix. The fracture toughness and strength of the matrix are negatively correlated with the total porosity. Microscopic analysis showed that high-volume fly ash is conducive to the ductility of ECC and the macroscopic experiments verify this finding from the microscopic analysis.

Avaliação da incorporação de finos de resíduos de construção e demolição (RCD) em matrizes cimentícias binárias e ternárias

“…A porosimetria por intrusão de mercúrio das pastas cimentícias binárias e ternárias são apresentadas na Figura 3.9 (a,b). As pastas apresentam poros predominantemente capilares, localizados entre as áreas dos mesoporos (tamanho de poros na faixa de 0,01 a 0,05 µm) e macroporos (tamanho de poros maior que 0,05 µm) (WU et al, 2020), com porosidade total variando de 31,05% a 26,45%. Mercúrio Introduzido (mL/g) As características das matrizes variam com os teores de substituição de CP por MCS, assim é necessário definir as propriedades pretendidas conforme a aplicabilidade de estudo.…”