A New Method for Estimating the Deformability Modulus of Plastic Concrete-gotvand Dam xperience,Southwest Iran

摘要

We present a new technique for estimation of the elastic modulus of plastic concrete. A mixture of typical concrete with clay and bentonite, plastic concrete has been widely used in recent years for developing diaphragm cut-off walls in many dam projects throughout the world. It is important to properly estimate the elastic modulus of plastic concrete for dam safety because it should be close to the elastic modulus of surrounding soil to withstand the imposed deformations without breaking up. a review of the literature showed that the existing methods for elastic modulus calculation are not so efficient and the obtained data are scattered. After several experiments, we noticed that the main problem associated with the error in modulus estimation is the way that the strain is being measured during the test. Therefore, we proposed a new technique for strain measurement. To resolve the problem, we changed the stain gauge arrangement and shortened the distance used for strain measurement. The strain gauge was directly connected to the sample. Using the new technique, the stress-strain curve of plastic concrete was significantly improved and showed more stable and reliable behavior. Good time-trend was observed for age-elastic modulus relationship of specimens using the new method.