INVESTIGATION OF CELLULAR GROUT AS AN ANNULUS VOID FILL MATERIAL FOR SLIPLINED CULVERTS

Abstract

Many culverts in Ohio are nearing the end of their design lives and have a risk of collapsing. Sliplining, a process where a pipe with a smaller diameter is inserted inside a host pipe and the annular gap between them is filled with grout, is a technique that is frequently utilized for the rehabilitation of culverts. In this study, a number of sliplined culverts in Ohio were subjected to field inspections, during which a hammer-sounding test method and backscatter computed tomography were used. These investigations showed that the annular spaces were not completely filled in. Consequently, the existing standards for grouting material established by the Ohio Department of Transportation (ODOT) require certain revisions. As cellular grouts were not described in depth in the ODOT specifications at the time of this research, the project’s primary objective was to conduct laboratory tests on these materials. The experiment in the laboratory considers various mix proportions in addition to applying various foaming agents to modify the material’s physical properties, including flowability, temperature, stability, and other characteristics. The impact on grout stability was detected when it had an extremely low density and when the cellular grout was exposed to a high temperature. In additional, it was discovered that the grout materials significantly impacted the load-carrying capacity of sliplined corrugated metal pipes. The current research aims to investigate the load-carrying capacity of the culverts sliplined with cellular grout as well as to investigate the effect of voids on the load-carrying capacity of the culverts by studying sliplined culverts with partially filled annular spaces. The findings of this investigation highlighted how critical it is to fill the annulus of sliplined culverts completely. A side-by-side comparison of partially filled annular spaces with voids at different positions revealed that voids in the crown position significantly reduce the load-carrying capacity of the culverts and are more consequential than voids in the springline position. Finally, large batches of cellular grout were tested in the field to confirm their pumpability and were installed in the annular spaces between two corrugated steel pipes in large scale field tests. It was determined that the cellular grout is suitable for the sliplining culverts, since it performed remarkably well when it came to filling annular spaces.