This article has now been updated as the PGL has now been superceded by the Nimbus Precision balance.

Nimbus Top Pan Precision Balance

There's no hard and fast rule that applies when creating the perfect concrete, but Adam Equipment's PGL precision balance can help pave the way to a better quality product.

Concrete is a composite material, which means it comprises of several ingredients, including fine and coarse aggregates, water, cement and air. There are myriad variables in every batch of concrete. Aggregates usually make up the bulk of the volume in concrete. Fine aggregate is sand; coarse aggregate is gravel or crushed stone. It's the combination and types of the fine and coarse aggregates that determine the density of the concrete. And while water is an essential ingredient, too much can cause quality problems.

The ideal concrete mix contains just enough water to hydrate the cement, which binds the ingredients. Without adequate hydration, the concrete is difficult or impossible to pour. As the concrete hardens, the water evaporates, leaving voids or spaces in the concrete. The size and number of voids are directly related to the amount of water used to hydrate the cement. More voids (and the larger they are) lead to a lower quality of concrete, possibly with defects that could compromise structural integrity.

Making Concrete

Construction standards are state-regulated and materials must meet or exceed them. Workers can verify a material's quality by performing a variety of tests for density, compressive strength, flexural strength, tensile strength, elasticity, permeability, thermal expansion, drying shrinkage and heat capacity. Adam Equipment's PGL precision balance provides an easy and accurate way to determine specific gravity of cured samples.

To perform specific gravity testing, the PGL precision balance is placed on a tabletop with a cutout or on a stand designed specifically for this test. A basket is attached to a wire that hangs from the balance's weigh-below hook and suspended over a container of water beneath the balance. After placing the sample material on top of the balance, the weight is recorded automatically by the balance. Next, the sample is placed in the basket and lowered into the container of water. The precision balance records the weight of the submerged sample, and using both measurements, the intuitive software calculates the specific gravity of the sample.

One company that values the PGL precision balance for testing the quality of concrete is Humboldt Manufacturing. Located in Schiller Park, Ill., Humboldt manufactures and distributes equipment for materials testing. Many Humboldt customers are in the road construction industry and include contractors, consultants, transportation department employees and lab workers.

According to Humboldt's Director of marketing Robin Bailey, Humboldt produces its own line of testing equipment, but offers products from other manufacturers, such as Adam Equipment, to provide a wider selection to customers. In many cases, Humboldt recommends the PGL precision balance for testing concrete. There are several reasons for that, Bailey suggests. Durability and price are the big advantages with the PGL precision balance, since users often work with dirty, heavy substances and want a product that can withstand rigorous use.

“When you're dealing with concrete blocks, obviously things are going to get scratched and dented. People realise they're just going to get messy,” Bailey said. “The nice thing about Adam scales is they hold up. That's a big deal.”

Adam Equipment's PGL precision balance is designed with features that are ideal for performing specific gravity testing on concrete or other construction materials. The PGL boasts overload protection to safeguard the balance against damage from excessive weight. The all-metal casing and large stainless steel pan make the PGL balances suitable for use in the field where dirt and grime are commonplace, as well as in lab environments. Power is provided by a standard AC adapter and rechargeable battery pack, allowing workers to keep the balance in the back of a truck and use it at a worksite, where electricity might not be available.