Influencing Factors Analysis of Mechanical Properties of Fiber Cement-based Composites

ZHANG Wei; JIAN Bowen; HUANG Shimou; WANG Tao; WANG Chaosheng; CHENG Jiajia

doi:10.15926/j.cnki.issn1672-6871.2024.06.004

Abstract：In order to improve the poor tensile toughness and poor deformability of traditional concrete,nine kinds of dumbbell-shaped and prismatic specimens of engineered cement-based composite(ECC)were prepared.The effects of fiber volume content,water-binder ratio,sand-binder ratio,and fly ash content on the mechanical properties of ECC were analyzed through uniaxial tensile and flexural and compressive tests.The stress of matrix 1 and 5 was analyzed by finite element software.The results show that the ultimate tensile strain of ECC increases with the increase of fly ash content.The maximum strain value is 5.21％,and the tensile stress decreases accordingly.When the water-binder ratio is lower than 0.33,the tensile strain will be significantly reduced,but the tensile stress is higher than 2.8 MPa.When the sand-binder ratio is greater than or less than 0.36,the tensile properties of ECC will be reduced and the number of cracks will be reduced.The optimum content of nine matrix fibers is 2.0％.Nine kinds of ECC all produce strain hardening and multi-crack cracking,among which the crack development of matrix 1 and matrix 5 is excellent and the finite element stress analysis results are basically consistent with the experimental results.Excessive fly ash content will significantly reduce the compressive strength of ECC,but due to the effect of fiber bridging and crack prevention,the flexural strength will increase.The bridging effect of adding fiber into cement matrix can significantly improve the deformation resistance and ductility of cement composite matrix,and the"ball effect"of fly ash can lubricate the fiber-matrix interface,reduce friction,and be beneficial to the formation of the ECC strain-hardening phenomenon.