The Relationships between the In-situ Tensile Strength Across Joints of an RCC Dam and the Maturity Factor and Age of Test

摘要

Cores are usually extracted from dams at various ages,due to the limitation of access and due to the progress of the placement of the concrete.Thus the specimens from the cores are frequently tested at ages that vary considerably.Therefore when considering the tensile strength of cores containing joints between layers,there are two variables; first the Modified Maturity Factor (that defines the exposure time between the layers and the ambient temperatures at the time,both these factors influencing the strength at the joints) and secondly the age of test.With RCC,containing high proportions of pozzolan,there can be a considerable increase in strength with age.Thus a three-dimensional model has been developed that relates the direct tensile strength across joints with the Modified Maturity Factor and the age of test.These models have been used for four darns in South-East Asia,for which several hundred results were available.The shapes of the four models were all different,and in two of them the tensile strength did not reduce as much as was expected with increasing maturity at the joints.It is considered to be important to be able to determine the shape of such 3D models for each dam so that the most economic solution can be developed for that particular dam.