ENHANCEMENT OF DEFORMABILITY OF HIGH-VOID-CONTENT CEMENTITIOUS MATERIALS

Abstract

The conditions for high deformability of the high-void-content cementitious composite（HVCC）material with voids formed by shells have been investigated by the numerical analysis. In the numerical analysis unit structural elements in which the shell, the mortar matrix, and the interface between them are modeled are used. The parameters examined in the analysis are such as the shape and stiffness of shell, and the mechanical properties of the interface. The influence of these parameters on the unit structural element has been clarified. Then, the deformation behavior of the entire material has been investigated by the macroscopic modeling of the structure of the unit structural element. From the present study on the mechanical behavior of a unit structural element, the following items have been clarified.（1）To make the deformational behavior of the HVCC material under compression ductile, it is effective to use circular shells.（2）To make the compressive strength of the HVCC material large, it is effective to make the strength and stiffness of shell large.（3）To make the shear strength of the HVCC material large, it is effective to make the interface strength large in case of circular shells and small in case of square shells. For the global mechanical behavior of the HVCC material, the average stress-strain relationships of the structural unit element under uniaxial compression and that under shear loading have been determined based on the consideration of the failure behavior of a unit structural element. Then, the overall model of HVCC material has been considered for uniaxial compression and shear loading, taking into account the statistical scatter in the mechanical properties. For the uniaxial compression an average stress-strain relationship of the HVCC material similar to the actual material has been obtained.