Giới thiệu bê tông hiệu suất cao (HPC) được định nghĩa là bê tông mà luôn luôn cung cấp các lợi thế thực hiện cụ thể về sức mạnh và độ bền để so sánh với bê tông thường. | Analysis of Early-age cracking in restrained ring specimens of high performance concrete using finite element method Dr. Nguyen Quang Phu Faculty of Hydraulic Engineering of Water Resources University Vietnam MEng. Do Viet Thang Hydraulic Construction Institute Vietnam Prof. Jiang lin hua College of Materials Science and Engineering Hohai University Nanjing 210098 China liujiaping Jiangsu Institute of Building Science Nanjing 210008 China 1. Introduction High-performance concrete HPC was defined as concrete which always provides specific performance advantages in terms of strength and durability to compare with the conventional concrete. Recently the use of high-performance concrete has increased. High-performance concrete mixtures are usually produced with water binder W B ratios in the range of - and incorporate with highly-active pozzolans such as silica fume SF fly ash FA and slag so it cannot avoid the volume changes occur in concrete as a result of drying self-desiccation chemical reactions and temperature change ACI Committee 209 1 . Hence the problems with early age cracking become prominent phenomenon. This paper used a numerical analytical study with finite element method FEM to predict cracking of high performance concrete in restrained ring specimens. There were a lot of methods to determine the early age behaviour of concrete under restrained shrinkage bar specimens plate specimens and ring specimens perhaps the ring test is the most common method applied to assess early age cracking in HPC s. When the concrete exposed to dry the shrinkage of concrete is prevented by the steel ring as a result for the tensile stress in the concrete develop. At the first days when the residual stress exceeded the tensile strength of the concrete that reason the early age cracking was occurred. The ring test method is simple in use the fact that is limited with respect to providing quantitative information on early age stress development and the exact conditions
