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

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.

Use of Polymeric Energy Absorption Liners to Improve the Concrete Rock Fall Barriers

“…Therefore, it is important to design proper rock fall barriers considering the site characteristics. As a significant disadvantage, concrete materials have relatively low impact strengths resulting from their brittle material properties [4][5][6]. Because of having poor impact energy absorption capacities, concrete barrier bodies can severely fail as basically shown in Figure 2.…”

“…The stress-strain curves of polymeric foams under the compressive loading case have three definite regions which are called linear elastic, plateau and densification regions (Figure 3). The polyurethane foams are quite ductile materials that densification continues instead of failure even under very high strain levels over 60 % [4]. Because of its deformability property, the polyurethane foam material was selected for the aim of supplying a good energy absorption capacity to improve the impact resistivity of the barriers.…”