Quality Tip: How to Avoid Excessive & Uncompensated Moisture in a Concrete Batch Plant

The most important part of a concrete mix design is the water-to-cement ratio. The ratio is the amount of water to the quantity of cement, typically both measured in pounds. This ratio is important for creating enough cement paste to be able to bind all of the other materials together. The materials in a concrete batch include stone, sand, cementitious powder and water. More complex mixes could include non-cementitious powders, admixtures, and fibers.

When the materials are used wet – above saturated surface dry (SSD) weight – the water in the material is included in the weight of material. For example, if your material has 5% moisture above SSD weight and you batch 1,000 lbs. of this material, you will have 50 lbs. of extra water and you will have only 950 lbs. of material. This affects two parts of the batch. First, it will result in 6 gal of extra water. Second, it will reduce the yield. This wastes cement because more cement is added than needed to paste a smaller amount of material together.

Excessive moisture can result in:

• Overly wet mixes: Too much moisture can make the mix too fluid, reducing strength and leading to segregation of material.
• Inconsistent strength: Variations in aggregate moisture cause fluctuations in mix proportions, leading to unpredictable compressive strength.
• Extended setting times: Higher water content can delay curing and setting, impacting production schedules.
• Surface defects: Excess moisture can lead to problems like scaling, cracking and poor finish quality.

Understand Stockpile Moisture Variations
Aggregate moisture levels can vary significantly depending on where material is sourced from within the stockpile. Different moisture levels arise due to the natural settling of water in the pile, particularly in rainy or humid conditions. Trucks may pick up materials from different sections of the quarry’s stockpiles, which will also affect the moisture content in the batch.

The loading of the bins should be done as close to the start of batching as possible, as this timing will make for more consistent moisture readings from probe. The longer the materials sit in the bins the more water drains to the bottom of the aggregate.

To mitigate the risk of excess moisture:

• Equipment operators should avoid taking aggregates from the bottom of the pile, as this area tends to retain more moisture.
• Operators should keep the bucket level at least 18” to 24” from the bottom of the pile.
• Whenever possible, aggregates should be taken from higher points in the stockpile where moisture levels are lower and more consistent.
• Frequently stir up the pile to redistribute the moisture in the pile.
• In rainy weather or hot weather covering the pile will keep the moisture in the pile more consistent.

By ensuring proper loading and stockpile protection practices, concrete producers can significantly reduce variations in moisture content and enhance mix consistency.

Regularly Test for Yield Compensation
Regular testing of aggregate content and proper stockpile management are necessary to ensure a consistent and high-quality concrete mix.

The frequency of testing depends on whether the plant has moisture probes installed.

• For plants with moisture probes installed: Testing should be conducted at least once a week to ensure proper probe calibration.
• For plants without moisture probes: More frequent testing is necessary, with moisture checks performed in the morning, late morning and mid-afternoon before the shift ends.

This routine helps maintain an accurate water-to-cement ratio and your yield, reducing the risk of excess moisture that can compromise your concrete’s performance.

Incorporate Moisture Burn off Testing into Daily Procedures
To improve overall product quality, it is important to formally integrate burn off tests into your plant’s daily operating procedures which includes; accurate material moisture testing, taking samples, weighing and the drying of the samples. Standardizing this procedure will ensure all team members will remain vigilant about moisture fluctuations and take corrective actions when needed.

By adopting these proactive strategies, concrete producers can prevent excess moisture and correct yields leading to a more reliable and durable final product. A well-maintained quality control process not only enhances product integrity but also minimizes costly labor, rework and material waste. Staying ahead of moisture-related challenges will contribute to a more efficient and successful concrete batching operation.

For more information on how Mixer Systems batch plant controls can ensure proper compensation for moisture, contact us today.

Nestled in Kingston in upstate New York, LHV Precast thrives as a leading producer of precast concrete materials, catering to diverse project needs while continually exploring new opportunities. Founded in 1979 by Dick and Clarice Willis, the family-owned enterprise evolved from a modest setup with a trailer, a phone, and a boom truck into a comprehensive operation offering an extensive range of products. Their lineup includes catch basins, manholes, electrical vaults, light pole bases, box culverts, three-sided spans, retaining walls, and custom solutions tailored to specific project requirements.

Jim and Bob Willis, the founders’ sons, grew up working in the plant but left to attend college. Returning home to help with the family business, today, Jim and Bob manage the plant, grooming the next generation to follow in their footsteps.

The company attributes its success from the Willis’ commitment to innovation and fostering strong partnerships with reliable suppliers. Mixer Systems, Inc., has been a key partner since the early 1980s, supplying mixers, accessories, and a complete batch plant. When LHV Precast’s old Prashak horizontal mixer, purchased in the early 1960s, needed to be replaced, Jim began looking for options. His visits to nearby plants highlighted the difficulties of sourcing foreign parts and having American-made equipment became a priority.

“When we were initially putting the plant together, we visited a few companies nearby to look at equipment, and they were having trouble getting foreign parts. It was at that moment we decided it needs to be made in America,” Jim explains. “We have had a relationship with Mixer Systems ever since.”

“In 1986, LHV Precast invested in their first Turbin Mixer from Mixer Systems, marking the beginning of our partnership,” according to Mixer Sales Manager Jonathan Jaruseski. After pouring over 400,000 yards of concrete over 35 years, the mixer is now retired and headed back to the Mixer Systems’ facility in Pewaukee to be put on display.

“When the time came to replace the mixer, there was no hesitation—Mixer Systems was our first choice,” Jim affirms. “Their products are backed by top-notch engineering and technical support, essential for our operations.”

In May 2021, LHV Precast began an ambitious project to expand its operations by constructing a state-of-the-art facility. This endeavor was carried out in collaboration with Mixer Systems and Emil Garlewicz of Concrete Plants, Inc., whose expertise was instrumental in shaping the new plant. “Emil Garlewicz, who recently passed away, was highly valued by Mixer Systems, as was his entire team at Concrete Plants, Inc.,” says Jaruseski. ‘’It was a smooth process with all of us working together to make sure LHV’s plant was exactly the way they envisioned.”

The expansion project included adding 21,600 square feet to the existing 14,400-square-foot building. The upgraded facility now features advanced components, including a new batch plant and additional aggregate and admixture silos, enhancing its production capabilities and efficiency.

“Mixer Systems was the logical choice to partner with on this project,” Emil stated. “Not only do they have some of the finest equipment available in the United States, they have the service and expertise to work alongside us.” The new facility includes a dedicated 3.5-cubic-yard batch plant with a Turbin Mixer from Mixer Systems. This setup includes a computerized washout, designed to streamline the cleaning process.

“The new facility, commissioned in February 2022 after rigorous certifications, underscores our commitment to growth,” says John Klassen, LHV Precasts’ CFO. “Our partnership with Mixer Systems is more than just transactional—it’s a collaborative effort where troubleshooting and support are readily available. There is always someone at Mixer that can assist with troubleshooting.”

“We want to keep growing the business,” Jim adds. “We are always looking for another product line, or another solution to offer. Because when it comes right down to it, people know the skill that we bring to projects, and we are in a good position to keep doing what we do.”

We are thrilled to announce during National Safety Month a significant milestone: Mixer Systems, Inc. has successfully completed one year without a single recordable accident! This achievement is a testament to the dedication and commitment of every team member to maintain a safe and secure work environment.

Mixer Systems, Inc. proudly announces its 45th anniversary in 2024. Established in 1979, Mixer Systems continues to be a leader in providing whole-plant solutions for concrete products in the industry and environmental markets worldwide.

“Since its inception, Mixer Systems has been committed to delivery exceptional products and customer service. Our highly skilled engineering staff works closely with our customers to develop tailored solutions to meet their specific needs. This commitment to customizations sets us apart,“ says Nicholas Passint, President of Mixer Systems, Inc. “Furthermore, all our products are designed and manufactured in America. We are grateful to all the customers who have supported us over the last 45 years and look forward to building new partnerships.”

Spanning an impressive 86,000 square feet, the Mixer System facility houses advanced product planning, state-of-the-art manufacturing, and the capability to design and construct concrete batch plants from the ground up. While the Turbin Mixer laid the foundation for the business in 1979, today Mixer Systems boasts four mixers – Planetary, Horizontal Shaft and Twin Shaft, and a comprehensive line of related components and accessories to design a batch plant precisely to customers’ specifications.

Mixer Systems’ product line represents the largest family of equipment in the industry, renowned for its American reliability and durability, standing up to the to the challenges of the concrete world. Visit www.mixersystems.com to see the complete line of products.

An old, rusted hulk of a batch plant turning out a nearly obsolete product. That was the situation confronting Harford Venture Group when it purchased Suscon Products (previously known as Suscon Stacks) near Baltimore. The new owners saw potential, but could the dilapidated plant that once supplied concrete smoke stacks up and down the East Coast rise from the rust?

“The company was pouring high heat stacks, but they weren’t environmentally acceptable, and the power industry was turning away from them,” said Alan Trebes, chief operating officer of Suscon. “When we first acquired the property, we just wanted to keep the store open.”

The broken-down batching and mixing equipment was long past its prime, however.

“We completely mothballed it,” said Miguel Lambert, Harford principal. “It was over 30 years old and in the center of the building, an unsuitable location for rebuilding.”

To stay productive Suscon devised a workaround, bypassing the ancient mixer and silos with ready-mix trucks driven into the plant to pour concrete in the product forms. Coordinating just-in-time arrival of the trucks was a constant challenge, though, and Suscon needed a better long-term solution. It was especially urgent as the company had set its sights on expanding production of concrete block for the profitable retaining wall market.

Suscon contacted Mixer Systems, Inc. (MSI), in Pewaukee, Wis., to renovate the plant. “We started by determining if the old equipment could be made operational again, but it was completely worn out,” said Jonathan Jaruseski, eastern US and Canada regional manager. “Instead, we proposed several different concepts for supplying new batching and mix-ing equipment to be installed where the existing equipment was.”

The costs for removing the old equipment and then doing an upgrade were prohibitive, however, sending MSI back to the drawing board.

“We quoted a completely new batch plant at the far end of the existing building that would not require demolition of the old equipment,” Jaruseski said.

The proposal included a plant in two modular sections: a mixer section and an aggregate section. Both were substantially wired and plumbed at the factory prior to shipment to reduce assembly time and start operation sooner.

“What I was most impressed with Mixer Systems was their initial engineering to help us design the flow of the plant,” Lambert said. “They looked at the products we wanted to manufacture and said, ‘Here’s a way for you to maximize production and minimize construction,’ and that was really helpful.”

Suscon had two stipulations: that the plan not make extensive modifications to the existing building and that Mixer Systems partner with a company to complete a turnkey erection.

MSI chose Concrete Plants, Inc., a contractor with which it had collaborated on other projects.

“Very, very few batch plants are identical and the Suscon site was unique,” said Denny Holmes, Concrete Plants area manager. “The mixer section was designed so it could be lowered into the building with no modifications. The customer was concerned about cutting the roof open and the clearance was tight—about a foot around. But we had no problem at all, and it went together perfectly.”

The entire installation was completed in about two weeks. The plant was built around Mixer System’s legendary Turbin mixer, with a capacity of 72 cu. ft. or 7,200 lbs. Other components included three aggregate storage bins, each with a 40-ton capacity, and two cement silos. Additionally, Concrete Plants, Inc. fabricated stairs and walkways for the facility.

Currently, Suscon operates one shift at the plant producing blocks for the Redi-Rock system of engineered retaining walls, shipped to Amazon warehouses, large contractors, and commercial developers. The smallest weighs about 700 lbs. and the largest just under 5,000 lbs.

“We’ve heard these called rather large, adult-size Lego blocks,” said Joshua Edwards, production manager at Suscon. “They’re able to be stacked into retaining walls as high as 15 feet without tiebacks using the system Redi-Rock has developed.”

From pouring the concrete mix to pulling the finished blocks from the forms takes about 16 hours. Crews begin the day breaking apart forms from the previous day’s production, then pour about 40 new blocks to be dried overnight.

“The mixer is at the back end of the plant on an elevated platform about 15-feet high,” said Edwards. “When the material is ready and the gates open, it flows into large ladles, or hoppers, and then is carried over the forms by a 10-ton crane.”

The forms have rubber molds on the bottom to create a natural, stone-like appearance. Once poured, the top of the blocks is troweled to a smooth finish. In all, Suscon mixes 30-35 batches a day, with some of the larger blocks requiring two-and-one-half batches and the smaller ones one-quarter batch. Each batch takes about five minutes, and the Turbin mixer typically runs two-and-one-half to three hours a day.

Suscon is unique in using recycled aggregate and sand in the mix from Repurpose Aggregates, an allied company located on the same site. Though the material is repurposed, the finished product must meet the same standards as virgin material. Suscon has an in-house test lab to check quality.

“Redi-Rock requires a target strength of 4,000 psi after 28 days, and we are actually at 4,500 psi,” said Edwards. “Overall, they’re looking for quality.”

With a dependable batch plant now thriving, Suscon is thinking ahead. “What we’d like to do is continue to increase production at our current facility and learn from this design-and-build,” Lambert said. “If we expand to another facility, we think Mixer Systems would be a great partner, even helping us evaluate an existing plant.”

New Owners Take the Controls at Mixer Systems, Inc. for the First Time in a Generation.

Pewaukee, Wis., July 25, 2023 — Mixer Systems, Inc., North America’s premier manufacturer of mixing and batching equipment for the concrete, glass, and environmental industries, today announced new ownership and promotions of the management team.

Family owners Lesley Hill and David Boles, who shared leadership of the company, sold a majority stake to a group comprised of a Milwaukee-based growth partner and Mixer executives. This is the first change of ownership outside the family since Mixer was founded by William Boles, father of Hill and David Boles, in 1979. The siblings retain minority ownership in the company.

As part of the ownership transition, Doug Duley, president of Mixer, has been promoted to CEO, and Nicholas Passint, general manager, has become president. In addition, Scott Adams, general manager of the DustMaster division, will be expanding his role with Mixer and taking on the GlassMaster product line.

“We’re extremely grateful to Lesley and David for their steady leadership in guiding Mixer forward after the death of William Boles in 2014,” said Duley. “While we’ll miss their energy and spirit, we congratulate them on their retirement and wish them well in spending more time with family and pursuing their passions outside of Mixer.”

The ownership and management changes are expected to bring new capital to Mixer and help position the company for significant growth in the years to come, while also maintain its innovative tradition. Mixer presently makes the largest line-up of mixers and related equipment in its industry.

“This is a truly exciting time for the company as we look to a new chapter of being an industry leader and continuing to provide the best possible solutions for our customers,” said Passint. “Our products will still proudly wear the ‘Made in America’ label to reflect the engineering, craftsmanship, and reliability for which Mixer is known worldwide.”

Contact: Nicholas Passint, 608-213-6429 mobile, nickp@mixersystems.com

A diversified economy and population growth are tempering the effect depressed energy prices would traditionally have had on the Texas construction market, where commercial building work held strong this year on the heels of surging 2013–14 activity. One of the most recent arrivals in architectural precast production, Enterprise Precast Concrete of Texas, LLC, is set to close out a year when historic rainfall totals—40 inches or more in some central and eastern parts of the state, or four times their normal annual precipitation levels—were as disruptive as oil dropping to $40/barrel. Read More