Experimental Study on Unconfined Compressive Strength of Basalt Fiber Reinforced Clay Soil

Lei Gao,Guohui Hu,Chao Xiang,Junyi Fu,Nan Xu,Chen Yang

doi:10.1155/2015/561293

Abstract

In order to study the mechanism and effect of basalt fiber reinforced clay soil, a series of unconfined compressive strength tests conducted on clay soil reinforced with basalt fiber have been performed under the condition of optimum water content and maximum dry density. Both the content and length of basalt fiber are considered in this paper. When the effect of content is studied, the 12 mm long fibers are dispersed into clay soil at different contents of 0.05%, 0.1%, 0.15%, 0.20%, 0.25%, 0.30%, and 0.35%. When the effect of length is researched, different lengths of basalt fibers with 4 mm, 8 mm, 12 mm, and 15 mm are put into soil at the same content of 0.05%. Experimental results show that basalt fiber can effectively improve the UCS of clay soil. And the best content and length are 0.25% and 12 mm, respectively. The results also show that the basalt fiber reinforced clay soil has the “poststrong” characteristic. About the reinforcement mechanism, the fiber and soil column-net model is proposed in this paper. Based on this model and SEM images, the effect of fiber content and length is related to the change of fiber-soil column and formation of effective fiber-soil net.

Highlights

Natural clay soil material has certain deficiency in the strength and stability of foundation
Based on the analyses of interaction between the basalt fiber and soil, this paper proposes that the basalt fiber reinforced clay soil has the “poststrong” characteristic and the fiber and soil column-net model is introduced
What can be seen from the figure is that the stress-strain curves of soil sample without fiber and basalt fiber reinforced soil samples are approximately linear at the initial stage, the axial stress increases with the increase of axial strain, and the rate is a little large

Summary

Introduction

Natural clay soil material has certain deficiency in the strength and stability of foundation. The mechanical properties of polypropylene fiber such as the tensile strength and elastic modulus are limited and its reinforcing effect is largely limited by the type of soil [4,5,6,7]. The basalt fiber has natural compatibility, excellent mechanical properties, high temperature, and acid and alkali resistance. It is widely used as the insulation, sound absorption, heat-resistant materials, and reinforced materials in thermosetting resin and concrete [8,9,10,11,12,13]. The mechanical properties like the tensile strength and elastic modulus of basalt fiber are significantly higher than those of polypropylene fiber. The results can be applied as the reference for basalt fiber reinforced clay soil engineering

Materials

Testing

Results and Analyses

Discussions

Conclusions