When Concrete Meets Plastic: The Revolutionary Science of Tougher Construction Materials

In a world of increasing environmental challenges and infrastructure demands, this innovative blend of polymer and concrete might just hold the key to more resilient construction.

Imagine a world where retaining walls can withstand decades of punishment without rusting, where concrete structures can absorb incredible impacts without shattering, and where construction projects require fewer raw materials while lasting longer. This isn't science fiction—it's the reality made possible by Tensar reinforced cement composites, a revolutionary advancement in construction materials that combines the strength of concrete with the flexibility and durability of polymer grids.

1970s

The story begins in the late 1970s, when Dr. Brian Mercer invented the 'Tensar process'—a method of stretching polymer grids to align the molecules in the ribs and junctions, creating unprecedented strength and durability ² . This innovation would soon transform how engineers approach construction challenges, particularly when structures face dynamic loads from impacts and explosions.

The Geogrid Revolution: How Plastic Reininvents Concrete

Molecular Alignment

The magic lies in Mercer's stretching process, which aligns the polymer's long chain molecules in both the ribs and through the junctions. This molecular alignment creates grids with exceptional strength and durability while maintaining flexibility ² .

Corrosion Resistance

What makes Tensar grids particularly valuable is their inherent resistance to water and chemical corrosion, addressing one of the most significant limitations of traditional steel reinforcement—rust and degradation over time ¹ .

The resulting product looks like a plastic web but performs with characteristics that surprised early skeptics who dismissed it as just "a bit of plastic" ² .

Under Fire: Testing Tensar's Dynamic Performance

The true test of any construction material isn't just how it performs under static conditions, but how it responds to sudden, violent impacts. In landmark 1984 research presented at a conference sponsored by the Science and Engineering Research Council and Netlon Ltd., scientists put Tensar reinforced cement composites through their paces under extreme dynamic loading conditions ¹ .

Impulsive Loading

From contact explosive charges

High Velocity Impacts

From armor-piercing bullets

High Mass Impacts

From a drop hammer ¹

Step-by-Step: Inside the Drop Hammer Experiment

Researchers created cement composite slabs reinforced with Tensar grids in controlled dimensions.

A heavy weight was dropped from a specified height onto the specimens, simulating high-mass, low-velocity impacts similar to what might occur from falling debris or machinery.

Advanced instruments measured the transient flexural response—how the material temporarily bends and vibrates during impact ¹ .

After impact, researchers quantified the damage using multiple parameters: crater volume, spall volume, crater diameter, spall diameter, and total crack lengths ¹ .

Some damaged slabs underwent static re-loading tests to determine how much strength the material retained after impact ¹ .

The methodology was rigorous, capturing both the immediate response to impact and the long-term implications for structural integrity.

Revealing the Numbers: How Tensar Performed Under Pressure

The experimental results demonstrated that Tensar-reinforced composites offered performance comparable to traditional steel reinforcement, but with additional advantages related to durability and corrosion resistance ¹ .

Table 1: Damage Parameters Measured in Dynamic Impact Tests
Damage Parameter	Significance	Measurement Approach
Crater Volume	Indicates material loss from direct impact	3D measurement of depression
Spall Volume	Measures fragments dislodged from opposite side	Volume calculation of spalled material
Crater Diameter	Shows spread of damage on impact side	Width measurement across crater
Spall Diameter	Reveals damage propagation through material	Width measurement of opposite side damage
Total Crack Length	Quantifies internal fracture network	Sum length of all visible cracks

Table 2: Comparison of Impact Test Methods and Their Real-World Correlations
Test Method	Impact Characteristics	Real-World Scenarios
Contact Explosive Charges	Impulsive loading	Blast events, industrial explosions
Armor-Piercing Bullets	High velocity, low mass	Ballistic impacts, projectile hazards
Drop Hammer	Low velocity, high mass	Falling debris, machinery impacts

Perhaps most impressively, the research concluded that "the structural performance of Tensar grids under dynamic loading is comparable with that of steel reinforcement" while offering additional advantages in corrosive environments ¹ .

Beyond the Lab: Real-World Applications and Lasting Impact

The implications of this research extend far beyond laboratory experiments. Since its initial development, Tensar geogrids have been used in thousands of projects globally, from earth retaining structures with design lives up to 120 years to critical infrastructure supporting roads, railways, and high-traffic areas ² .

Early Success: Newmarket Silkstone Colliery

One of the earliest real-world trials in 1980 at Newmarket Silkstone Colliery in Yorkshire saw Tensar geogrids used to build a temporary retaining wall supporting a railway. The performance "exceeded all expectations," with no discernible settlement over three years despite up to 300 tons of waste passing over the railway every hour ² .

Modern Innovation: TriAx Geogrid

More recent developments, like the 2007 introduction of hexagonal TriAx geogrid, have further advanced the technology, enabling even thinner pavement sections that use fewer materials while maintaining performance ² . This evolution continues to demonstrate the potential of polymer reinforcements to create more sustainable construction solutions.

1980

First real-world trial at Newmarket Silkstone Colliery exceeds expectations ² .

1984

Landmark research on Tensar composites under dynamic loads presented at conference ¹ .

2007

Introduction of hexagonal TriAx geogrid enables thinner pavement sections ² .

2013

Tensar named one of the British inventions of the 20th Century ² .

Conclusion: A Lasting Legacy

The pioneering research on Tensar reinforced cement composites under dynamic loads revealed more than just how a new material performs under stress—it unveiled a different approach to construction itself. By combining the compressive strength of concrete with the flexible, corrosion-resistant properties of polymer grids, engineers gained a powerful tool for creating more resilient infrastructure.

Nearly four decades after those initial explosive tests, Dr. Mercer's conviction that Tensar would be revolutionary has been proven right. As we continue to face challenges in building sustainable, durable infrastructure in an era of climate change and resource constraints, the science of reinforced composites may hold critical answers for constructing a world that can withstand whatever forces it encounters.