Effect of adding glass fibers on durability to freeze-thaw cycle of epoxy resin stabilized silty sand

Abstract

It is a good practice to change the site soil properties when dealing with inappropriate soils in geotechnical engineering, referred to as soil improvement. This study investigated the effects of epoxy resin LR202 stabilizer (5 wt% of soil as an optimum percentage) and glass fibers (0 wt%, 0.4 wt% and 0.8 wt% of stabilized soil) as reinforcement on silty sand’s durability. For this purpose, the unconfined compressive strength test (12 tests), durability test (12 tests), ultrasonic pulse velocity (UPV) test (48 tests), and standard compactions test (5 tests) were performed. The results of this study showed that the addition of epoxy resin improves the durability of silty sand soil. The stabilized samples containing 5 wt% epoxy resin resisted 12 freeze-thaw cycles, and the sample behavior was enhanced by adding 0.4 wt% and 0.8 wt% fibers to the stabilized samples. Hence, the samples stabilized with epoxy resin exhibited acceptable behavior under freeze-thaw durability cycles. This indicates that epoxy resin stabilizer is appropriate in areas with possible frost and exhibits good behavior. The results of the UPV test showed that it could be used as a non-destructive test to control the durability of epoxy resin-stabilized soils.

1. Introduction

The mechanical qualities of soil can be improved by using soil improvement techniques, which have seen widespread use. These techniques alter the features of soil to enhance the soil’s mechanical properties. The proliferation of soil improvement strategies can be attributed to their practicability and cost-effectiveness [1−3]. Soil improvement is the process of changing the qualities of the soil to improve its engineering performance. This process is also known as soil stabilization. Strength, durability, volume stability, and compressibility are the primary characteristics of soil that are important to engineers [4−6]. Additionally, permeability is a critical factor that affects the hydraulic behavior of soils.

Chemical additives such as cement, lime, and fly ash have shown favorable aspects of stabilizing soft and unstable soils. Studies have shown that increasing the cement content increases the maximum shear strength, cohesion, and stiffness, while the residual and ultimate strengths do not change during cementation [7, 8]. The use of traditional stabilizers such as cement, lime, and fly ash to improve the behavioral properties of soil has long been considered by engineers. However, due to environmental issues, conventional chemical stabilizers are usually only sometimes readily accepted. Traditional stabilization methods often require extended curing time and relatively large amounts of additives to improve strength significantly. Some stabilized nontraditional additives are increasingly available for commercial and military applications.

In recent years, using epoxy resins for soil stabilization has been considered. These epoxy resins have shown their ability to be used as additives for soil stabilization [9, 10]. To overcome such problems, it is necessary to use an alternative stabilizer capable of improving soil strength and durability without damaging the environment. In civil engineering, polymer materials such as epoxy resins have been utilized to repair and rehabilitate concrete pavement materials and concrete buildings [11−13]. In addition, epoxy resin can be used as a component of the stabilization substance employed to enhance the mechanical qualities of the soil. In addition to this, the use of epoxy resin as a stabilizer can improve a variety of various aspects of the soil [14−17]. TINGLE et al [16] investigated the influence of several resins on the cohesive soil’s unified, cohesive strength (UCS), and tensile strength, and they found that resins could boost the cohesive soil’s strength significantly. In a series of tests, RAUCH et al [18] investigated the impact of various unconventional stabilizers on treating multiple clays. They concluded that the soil’s qualities were improved thanks to these stabilizers. On the other hand, their growth is distinct, as it is determined by the aggregation of the soil and the kind of resin.

In recent years, an additional study has been undertaken on the resin-sand combination’s mechanical qualities, such as strength. AL-KHANBASHI et al [19] evaluated the effect of three water-born polymers as a stabilizer for sandy soil. Their results demonstrated increased modulus of elasticity and UCS of the studied emulsions by increasing the concentration of polymer. KUTANAEI et al [20