An Investigation of Foam Concrete Usability as a Cavity Filler Material in Mining

Eren Kömürlü

doi:10.35180/gse-2021-0054

Abstract

Strength and deformability properties of different cavity filler materials of a phenolic foam, a polyurethane based foam and a foam concrete (FC) mix were investigated and compared in this study. Instead of using polymeric foam fillers, FC usage was found to supply better load bearing capacity and modulus of elasticity values. The fresh FC mixes consisting of cement, water and foaming agents are able to be filled into the mine cavities. In the cavity filling applications, typical polymer foams cause support reactions with low stiffnesses and let the rock mass at the roof to be loosened. A relatively stiff cavity filling material can help rock masses to bear itself by prevention of the loosening. To avoid excessive deformations of the rock masses, the deformation modulus is an important parameter as well as the strength property. The FC filler materials were found advantageous because of economical supply of improved load bearing capacities and stiffness values for controlling the rock mass convergences.

Highlights

In mining and tunnelling applications, the cavities can occur due to the overbreaking in excavations and/or rock block falls due to the lack of the needed support pressure
foam concrete (FC) specimens were poured into the moulds with same geometry and sizes of polyurethane foam (PF) and FF specimens. 14-day-cured cubic FC specimens were weighed before mechanical tests and evaluated to have the mean density value of 640 kg/m3
According to the results, following research findings can be noted as conclusion matters: 1. The FC filler material is more economical in comparison with the widely used polymeric foam materials to supply relatively high strength values

Summary

Introduction

In mining and tunnelling applications, the cavities can occur due to the overbreaking in excavations and/or rock block falls due to the lack of the needed support pressure. To prevent progressive block loosening and major collapses, filler materials are pumped into the cavities. The polymeric foam fillers are widely preferred because of their ability to conform to the shape of the cavities and supplying good contact to rock surfaces. The polymeric foams have low densities and make low pressures on the support elements like concrete liners, steel sets, etc. The polymeric foams have good chemical resistivity which is an advantage for their usability in rock engineering. The ability to solidify soon after pumping into the cavities supplies load bearing capacity in early times [1,2,3]

Methods

Results

Conclusion