A Novel Application of the Hydrophobic Polyurethane Foam: Expansive Soil Stabilization

Abstract

The reversible shrink–swell behavior of expansive soil imposes a serious challenge that threatens the overlying structures’ safety and durability. Traditional chemical additives such as lime and cement still exhibit satisfying performance over their counterparts in terms of swelling potential reduction. Nevertheless, significant concerns are associated with these chemicals, in addition to their environmental impact. This paper proposes a novel application of the closed-cell one-component hydrophobic polyurethane foam (HPUF) to stabilize the swelling soil. An extensive experimental study was performed to assess the efficiency of HPUF in mitigating both the swelling and shrinkage response of high montmorillonite content expansive soil. Expansive soil was injected/mixed with different weight ratios of the proposed stabilizer, and the optimum mixing design and injection percentage of the foam resin were identified to be ranged from 10% to 15%. The shrink–swell behaviors of both injected and noninjected samples were compared. Results of this comparison confirmed that HPUF could competently reduce both the swelling potential and the shrinkage cracking of the reactive expansive soil, even after several wet-shrink cycles.

Soil Injection Technology Using an Expandable Polyurethane Resin: A Review

“…In 2021, Al-Atroush et al [101] performed an extensive laboratory experiment to assess the efficiency of the closed-cell hydrophobic polyurethane foam in mitigating the high swelling and shrinkage response of montmorillonite content Na-bentonite clay. The results have shown that, even after several wet-shrink cycles, the polyurethane resin effectively reduced the swelling and shrinkage potential of the reactive expansive soil.…”

“…It was found that degradation does not occur except in some instances. Different studies on the degradation of PUs to fungal attacks [100][101][102] revealed that polyester PU is more vulnerable to fungal and microbial attack than polyether PU. On the other hand, polyether PU is moderately resistant to fungal and microbial attacks.…”

Triethoxysilane End-Functional Branched Waterborne Polyurethane Adhesives for Leather Substrates

“…Polyurethane (PU) adhesives have strong polarity and chemical activity because of their urethane and isocyanate groups, so they can form strong bonding with substrates containing active hydrogen and a variety of pores, such as wood, leather, paper, fabric, ceramics, etc. − Meanwhile, they can also have good chemical adhesion with some substrates with a smooth surface, such as metals, plastics, rubber, glass, etc. , Although traditional solvent-based PU adhesives play an important role in many fields, they cause serious pollution to the environment but also they will increase the full utilization of petroleum resources. − In contrast, waterborne polyurethane (WPU) adhesive is characterized by non-toxicity, environmental protection, as well as safe storage and transportation. WPU adhesive is used in shoe-making, packaging, construction, automobile, medical and health care, aerospace, and a wide range of general bonding. − However, the introduction of hydrophilic groups leads to the deterioration of water resistance, mechanical properties, and thermal stability of the WPU film; as a result, its application in some fields is limited. , …”

Flexural Response of Concrete Specimen Retrofitted with PU Grout Material: Experimental and Numerical Modeling

“…Polyurethane gout materials have been used in several repair projects, including highway crack treatment, high-speed railway track slab raising, emergency reinforcement of water conservation projects, and repair of rigid pavement [15][16][17][18], as depicted in Figure 1. Similarly, closed-cell one-component hydrophobic polyurethane foam can be used to stabilize expansive soil [19], whereas polyurethane grouting materials are employed for repair of road and runway facilities [20]. The numerical analytical method has been utilized to investigate the performance of concrete materials under static loadings, which is considered isotropic and homogenous for numerical simulation [21][22][23][24].…”