Testing of Strainmeter Grouts: Observations on Workability vs. Strength of Expansive Grouts

UNAVCO has been conducting comprehensive testing of grouts for strainmeter installs between fall 2006 to spring 2008. These experiments have involved both workability and strength testing. Based on the results of these tests a final test was to install a strainmeter and observe data quality. The characteristics we looked for in the initial testing were a long working time, compatibility with our dump bailer and low viscosity. Test involved small scale mixes, flow cone testing, and full scale surface penetration testing. These were all performed over a range of water contents and temperatures. Samples from all testing were subject to compressive strength testing. Concerns we had with grouts were aggregate size and composition, fluidity, temperature sensitivity, and set time. The final result of this testing is the selection of a grout that has so far provided high quality data and shown to be workable over a broad range of install conditions.