Assessing strain rate sensitivity of cement paste at the micro-scale through micro-cantilever testing

This study presents an experimental investigation of the rate-dependent mechanical properties cement paste at microscale. With use a nanoindenter, micro-cantilever beams with size 300 μm × 1650 were loaded five different strain rates from around 10−6/s to 10−2/s until failure. It is found that increasing rate, stress-strain curves show less and delayed pre-peak nonlinearity. Both flexural strength elastic modulus increase while peak stress exhibits opposite trend. Examination fracture surface indicates rate possibility crack pass through stronger components hydration products increased. The observations possible mechanisms leading changes in responses are discussed. suggested least two micromechanical processes, namely creep Stéfan effect, mainly responsible for behaviour within investigated range their dominances seem vary rate. At lower sensitivity thought be dominated by higher effect appears governing factor.