Internal Viscoelastic Modulus Associated with Autogenous Shrinkage in Cementitious Materials

摘要: Abstract The principal objective in this paper is to determine the internal viscoelastic modulus associated with autogenous shrinkage of cementitious materials. This accomplished by analyzing plain and reinforced paste mortar specimens. restraint from steel reinforcement creates uniaxial tensile stress condition in-creasing shrinkage. Data analysis demonstrates a unique modulus, which eliminates need for relaxation calculations. range 8000-9000 MPa, while external com-posite known as Young’s 32 000-36 000 MPa low water-binder ratio (0.35) concrete. 1. Introduction Self-induced stresses develop concrete if movements caused cement hydration reactions are restrained (Bosnjak 2000). During early age two active mechanisms involved producing these movements, starting thermal effects domi-nate during first 24-48 hours. Self-desiccation another consequence proc-ess consumes water into solid products (Copeland Bragg 1955). As proceeds in-ternal pore drying develops development capillary tension pores (Koenders 1997). These transferred compression subsequent type autoge-nous It characterized uniform volume reduction at any time material property (that is, no moisture gradient), whereas devel-opment size-dependent non-uniform. Thermal relatively short-term acting throughout composite, time-dependent primarily on porous hy-dration products. Autogenous intensified high perform-ance (HPC) (W/B) (relative conventional concrete) due its generally higher content, reduced W/B, pozzolanic mineral admixtures. Prior results indicate that cementi-tious systems containing slag produces greater later ages (Hanehara