221 / 2022-06-10 15:30:08

Strain-hardening cementitious composites with high volume fly ash and non-oiled PVA fibers

Polyvinyl Alcohol Fiber; Uniaxial Tensile; Fiber Pullout; Strain-Hardening; Multiple-Cracking

Strain-hardening cementitious composites (SHCCs) were produced with cement pastes containing high volume fly ash as matrices and using low cost non-oiled PVA fibers as reinforcement. A part of fly ash acts as a supplementary cementitious material. Besides, the large amount of unreacted fly ash particles plays the role of fine aggregate. With the increase in fly ash content, the 28 d compressive strength of the matrix declined within the range of 93~18 MPa. The strength range is consistent with that of most existing PVA-SHCCs. The results for uniaxial tensile tests are shown in Fig. 1, indicating that the influence of fly ash at 20% and 50% dosages by mass fraction is insignificant. With the fly ash dosage increasing to 67% and 80%, the multiple-cracking and strain-hardening characteristics of SHCC tend to be enhanced. Especially, the composite with 80% fly ash and non-oiled PVA fibers exhibits ultra-high ductility with an ultimate strain up to 7.2%. Also, the SHCCs have a light weight, and the density is as low as 1 490 kg/m³ for the case with 80% fly ash. SEM observation on tensile specimens confirms that PVA fibers were mostly pulled out without rupture with the presence of high volume fly ash.