Compressive Strength: Plastic vs. Concrete

Posted on November 29, 2022

Compressive strength is a measure of a material’s ability to resist failure under compressive loads, or “squeezing” forces. Compressive strength testing is essential for quality control in the manufacturing process, as well as for safety and performance evaluations of completed structures. 

Compressive Strength: Plastic vs. Concrete

The compressive strength of concrete is derived from a combination of cement, water, aggregate, and air. The cement and water form a paste that coats and binds the aggregate together. The hydration process of the cement and water chemically reacts and produces calcium-silicate-hydrate and hydrates. This hydration process continues for years, slowly gaining strength. The air content is typically around 6-8% and is required for proper curing. Too much air will decrease the concrete’s compressive strength.

Concrete has a high compressive strength compared to other building materials. Due to its composite nature, made from cement, water, aggregate and air, it gains strength over time in compression. However, it remains relatively weak in tension. 

Plastic is a man-made material that can be molded or extruded into objects or films. It’s made from synthetic polymers that are derived from fossil fuels like natural gas or petroleum. The most common plastics are polyethylene (PE), polypropylene (PP), polystyrene (PS), polyvinyl chloride (PVC) and acrylonitrile butadiene styrene (ABS). While there are many different types of plastic, they all share some key properties like being lightweight, durable and low-maintenance. Plastics are also impervious to water and many chemicals. 

Plastics have a lower compressive strength than concrete but are much stronger in tension. They are also very lightweight which makes them ideal for applications where weight is a factor, such as in aerospace or automobile manufacturing. 

“Plastic pipe arrives on site as a non-structure, at about 10 percent of the installed system’s required strength, and requires proper contractor installation and recommended fill materials to reach its manufacturer-specified service strength.” –

The Importance of Testing Compressive Strength

Compressive strength testing is essential for quality control during the manufacturing process. By measuring the compressive strength of finished products, manufacturers can ensure that their products meet the required specifications. In addition, compressive strength testing can be used to identify potential defects in the manufacturing process so that corrective action can be taken. 

Compressive strength testing is also important for safety and performance evaluations of completed structures. For example, if a concrete bridge were to collapse, an investigation would be conducted to determine if the concrete had been properly tested and if it met the required specifications. If it was determined that the concrete had not been properly tested, or that it did not meet the required specifications, then steps would be taken to prevent similar failures in the future.