INTERFACE PROPERTIES FOR CONCRETE AND ROCK

Abstract

Evaluation of interface shear parameters between concrete to concrete interface or between concrete to rock interface or between rock to rock interface are required for the design of some important structures like nuclear power plants, dams etc. the evaluation of the - strength parameters becomes essential because when the super structures are founded the normal and shear forces imposed by these structures are in turn passed on to the interfaces thus endangering the sliding stability of the structure. Therefore, for ensuring the stability of the structure against possible shearing/ sliding the evaluation of shear parameters becomes essential and thus the necessity of conducting shear tests cannot be avoided. Evaluation of interface parameters can be carried out in situ as well as in laboratory by conducting direct shear test. In this thesis, evaluation of interface properties between concrete to concrete interface and between concrete to rock interface is done. For finding friction coefficient 'p 'between different interfaces shear tests on large size sample are to be done. At present the standard size of shear box available has a sample size of 6cm x 6cm and height 1 cm and this is too small for evaluating the interface shear parameters between concrete to concrete interface or between concrete to rock interface or between rock to rock interface. Hence I have used a large size shear box which can accommodate sample of size 20cm diameter and 10 cm height which is fabricated in the department of earthquake engineering. Concrete samples of 20 cm diameter and 5 cm height of M60 strength are prepared and tests are conducted on concrete and rock samples 1. By varying the normal loads from 25 kN to 125 kN while keeping strain rate constant at 0.05 mm/sec. 2. By varying ramp rates from 0.05 mm/sec to 1 mm/sec while keeping normal load constant at 75 kN.