Low-strength cellular concrete is a type of controlled low-strength material (CLSM) which is increasingly being used for various modern construction applications. Benefits of the material include its ease of placement due to the ability of cellular concrete to self-level and self-compact. It is also extremely lightweight compared to traditional concrete, enabling the concrete to be used in fill applications as a compacted soil would customarily be used. Testing of this material is not extensive, especially in the form of large-scale tests. Additionally, effects of skew on passive force resistance help to understand performance of a material when it is used in an application where skew is present. Two passive force-deflection tests were conducted in the structures lab of Brigham Young University. A 4-ft x 4-ft x 12-ft framed box was built with a steel reaction frame on one end a 120-kip capacity actuator on the other. For the first test a non-skewed concrete block, referred to as the backwall, was placed in the test box in front of the actuator. For the second test a backwall with a 30° skew angle was used. To evaluate the large-scale test a grid was painted on the concrete surface and each point was surveyed before and after testing. The large-scale sample was compressed a distance of approximately three inches, providing a clear surface failure in the sample. The actuator provided data on the load applied, enabling the creation of the passive force-deflection curves. Several concrete cylinders were cast with the same material at the time of pouring for each test and tested periodically to observed strength increase.The cellular concrete for the 0° skew test had an average wet density of 29 pounds per cubic foot and a 28-day compressive strength of 120 pounds per square inch. The cellular concrete for the 30° skew test had an average wet density of 31 pounds per cubic foot and a 28-day compressive strength of 132 pounds per square inch. It was observed from the passive force deflection curves of the two tests that skew decreased the peak passive resistance by 29%, from 52.1 kips to 37 kips. Various methods were used to predict the peak passive resistance and compared with observed behavior to verify the validity of each method.
College and Department
Ira A. Fulton College of Engineering and Technology; Civil and Environmental Engineering
BYU ScholarsArchive Citation
Black, Rebecca Eileen, "Large-Scale Testing of Low-Strength Cellular Concrete for Skewed Bridge Abutments" (2018). Theses and Dissertations. 7708.
abutment, backfill, cellular concrete, controlled low-strength material, lateral resistance, passive force, passive pressure