Controlled Low Strength Materials (CLSM) revolutionized backfilling trenches when it hit the market in the 1960s. As more and more utility lines move underground, the demand for this unique construction product is on the rise. As a ready-mixed concrete operator, keeping up with customer demand while still providing a quality, cost-effective product has its challenges. That’s why Fritz-Pak developed our CLSM concrete admixture, Fill Flow. This powerful additive not only improves the quality of CLSM but also increases the volume with less water.

Why is CLSM So Popular?

Before the 1960s, trenches were backfilled with compacted dirt. The advent of flowable fill mixes opened the door to a whole new way of burying utility lines. Dirt compaction requires expensive equipment and a great deal of time. It also comes with the risk of damaging the pipes or cables in the trench. In comparison, controlled low-strength materials are placed directly from the ready-mixed trucks, flow around the utility lines – insulating them from damage – and require significantly less time and money for placement.

How is CLSM designed?

Traditional CSLM mixes are made with a very high water-cement ratio to meet the lower psi requirements. While the extra water lowers the strength of the mix, it can also produce excess bleed water and increase segregation if the mix is placed via a concrete pump.

Fritz-Pak’s Fill Flow admixture contains a powerful foaming agent that generates thousands of air pockets in the mix. These air pockets decrease the overall strength of the mix without changing the water-cement ratio. They also increase the volume of the CLSM, so you can make more with less materials.

Learn More

Check out our product demonstration video to see the difference Fill Flow can have on your controlled low strength materials. Don’t forget to follow our social media accounts for more information about how our products can improve your concrete.