How Contractors Can Strengthen Our Roads & Highways

Far more than just physical connections between cities, our nation’s road and bridge systems are the lifelines of our economy and daily life, enduring relentless loads, severe weather, and chemical assault. Despite their robust design, these structures are deteriorating at an alarming rate. According to the American Society of Civil Engineers, the average age of U.S. bridges now exceeds 45 years, and nearly 43 percent of roadways are rated in poor or mediocre condition. Freeze-thaw cycles, deicing salts, and ever-increasing traffic accelerate this decline, causing cracks, spalling, corrosion, and structural degradation.

Concrete contractors are uniquely positioned to slow and even reverse this downward trend. They have the opportunity not only by building better from the outset but also by proactively protecting and rehabilitating existing assets. With constrained budgets and mounting maintenance backlogs, these solutions must be realistic, field-proven, and technically sound. There are actionable strategies that contractors can implement today to preserve our nation’s transportation infrastructure for decades to come.

Cracking the Code: How Concrete Deteriorates & Why It Matters

Durability begins at the mix design stage.

Concrete is one of the most durable construction materials, yet it remains vulnerable to water penetration, chloride ingress and steel corrosion. Once microcracks form within road or bridge structures, water and chlorides start to infiltrate the matrix, initiating a slow but relentless cycle of damage. Chlorides accelerate corrosion of embedded steel, which expands as it rusts, causing delamination, spalling, and ultimately undermining structural integrity. Even the smallest fissures can serve as capillary pathways for aggressive agents, and microstructural damage compounds over time.

The science behind concrete deterioration underscores the importance of early prevention. Chloride thresholds, diffusion rates, and carbonation depth are all measurable indicators that concrete contractors can monitor to assess risk of deterioration. Laboratory and field tests, such as chloride profiling, resistivity testing, and core sampling, allow for data-driven assessments. Understanding how local climate, traffic loads, deicing practices, and even concrete mix chemistry affect deterioration mechanisms enables contractors to tailor their interventions most effectively.

Building Resilience into New Construction Designs

Durability begins at the mix design stage. High-performance concrete designed for low permeability — achieved by reducing water-to-cement ratio, adding supplementary cementitious materials like fly ash, slag or silica fume, and optimizing aggregate grading — significantly reduces moisture and chloride ingress. Air entrainment improves freeze-thaw resistance, while integral waterproofing admixtures can reduce capillary absorption and enhance internal density.

Specifying epoxy-coated, stainless steel or galvanized reinforcement and ensuring appropriate concrete cover depth further enhance this resilience. Reinforcement detailing that avoids congested rebar and provides uniform cover improves both durability and constructability. Quality curing practices like timely moisture retention, temperature control and avoidance of premature drying are also critical to develop a dense microstructure that resists external attack.

Incorporating performance-based, rather than rigid prescriptive, specifications gives contractors the flexibility to achieve durability goals while exploring innovative materials and methods. Engaging designers early fosters collaboration, ensuring that durable details are constructible and cost-effective without unnecessary delays, while also encouraging creative yet practical solutions from both sides.

Bridge deck sealers provide invisible but powerful protection against water and chloride intrusion — extending the life of exposed concrete elements.The Euclid Chemical Company

Protective Treatments That Seal the Surface & Close the Gaps

Advanced joint systems like precompressed foam sealants, strip seals and modular expansion joints maintain watertightness under dynamic loads while extending the life of bearings, beam ends and substructures.

Surface-applied treatments and joint sealing represent the first line of defense against environmental attack. Silane or siloxane-based penetrating sealers chemically bond within the pore structure to repel water and chlorides while preserving breathability. Advanced formulations can penetrate several millimeters, providing long-lasting protection even in harsh freeze-thaw and high-salt environments. Some even help to mitigate alkali-silica reaction and provide resistance to UV degradation.

For areas of extreme exposure or heavy wear on road and bridge surfaces, epoxy, polyurethane or polyurea coatings form an impermeable, durable barrier that shields concrete from water, salts and aggressive chemicals. Selecting the correct coating system requires careful consideration of film thickness, abrasion resistance, vapor permeability and expected reapplication cycles.

Equally critical are cracks and joints, which act as penetration pathways for water and chlorides. Dormant cracks can be sealed with low-viscosity epoxy or polyurethane resins to restore monolithic integrity. For wider or dynamic cracks, flexible elastomeric sealants maintain a waterproof seal despite movement. Bridge deck joints and expansion seals often deteriorate under repetitive traffic and environmental stress, allowing contaminants to bypass surface protections. Advanced joint systems like precompressed foam sealants, strip seals and modular expansion joints maintain watertightness under dynamic loads while extending the life of bearings, beam ends and substructures.

And let’s not forget surface preparation, which is a crucial step for both treatments and sealants. It requires thorough cleaning to remove contaminants, opening pores through shot blasting or hydrodemolition, controlling moisture content and following manufacturer specifications precisely. Even seemingly minor missteps like leftover dust, inadequate roughness or excess moisture can undermine adhesion and effectiveness, underscoring the importance of meticulous preparation.

Modern joint systems help maintain watertight seals under heavy traffic and temperature swings, critical for protecting vulnerable areas like deck joints and beam ends.The Euclid Chemical Company

Advanced Mitigation Techniques for Steel Protection

When embedded steel has already begun to corrode, or in aggressive environments where prevention alone is insufficient, contractors can deploy electrochemical techniques. Cathodic protection applies a controlled current or sacrificial anodes to neutralize the corrosion process. Ideal for high-value or critical structures, impressed current systems allow for precise and ongoing adjustments of protective currents. By contrast, galvanic anodes offer a simpler, passive solution for many bridge elements.

Surface-applied corrosion inhibitors offer a less invasive but effective option. These compounds — amines, nitrites, or blended organics — diffuse through the concrete and form a protective layer on the steel. Selection depends on factors like chloride concentration, depth of contamination, compatibility with sealers and overlays, and pH of the concrete. For comprehensive protection, inhibitors can also be incorporated directly into the repair mortars, overlays, or grout used in rehabilitation work.

Contractors should also become familiar with emerging hybrid techniques for corrosion mitigation, which combine sacrificial anodes with intermittent impressed current to extend service life with lower maintenance demands. It’s important to carefully monitor corrosion rates both before and after installation, which helps to verify effectiveness and guide maintenance planning.