Johnson Concrete Products

hardscape products, dedicated to serving the construction needs of architects, contractors, and homeowners across the United States.

The Salisbury location of Johnson Concrete Products facilities specializes in the production of reinforced concrete pipe (RCP) for stormwater management. The plant caters to customers such as NCDOT, commercial grading contractors, and water works distributors. The dedicated team at the Salisbury location works diligently to maintain the high-quality standards that define their operations and has been recognized nationally for their quality control program and plant processes.

Johnson Concrete Products was experiencing two significant issues with the pipes they cast. Firstly, they were unable to achieve the smooth finish required, in addition to the appearance of minor bug holes. Secondly, they faced challenges in achieving the necessary early strength for the pipes.

A solution was needed that involved using a high performance admixture capable of providing a smoother, more appealing finish while minimizing bug holes and improving the ultimate strength of the pipes.

To address the customer’s issues, DCP recommended using its unique water reducing admixture Donplast ES1000, which is specially formulated for use with dry-mix concrete to allow for better compaction, higher early strength, smoother finish, and minimal bug-holes.

Achieving the optimal slump, workability, and setting time for casting the pipes using a drymix concrete demands the precise selection of plasticizing admixtures to ensure consistent, high-quality results. Therefore, Donplast ES1000 was selected.

Donplast ES1000 is a chloride free, premium quality plasticizing admixture based on polycarboxylic polymers with selective additives which are especially formulated for machine-made (dry-cast) concrete products.

Donplast ES1000 is specially formulated to improve the manufacturing efficiency, consistency, and visual appeal (swipe) of dry-cast concrete products.

After incorporating Donplast ES1000 into the pipe mix design using DCP’s specialized direct feed admixture dispensing system, significant improvements in the ultimate strength of the pipes were observed. The pipes’ finish was notably enhanced, with minimal bug holes, ensuring every pipe meets the highest standards.

To further improve on the strength of pipes, DCP incorporated the use of its unique hydration controlling admixture Donplast HC3, which is added at a specific dosage rate to improve the curing process allowing for additional strength gain without affecting the setting time of concrete.

Donplast® ES1000

After fabricating, welding, and aligning the reinforcing steel in the molds, the dry concrete mix treated with the optimum dose of Donplast ES1000 is cast. The concrete is then compacted using a vibrating table to ensure proper consolidation. Immediately after compaction, the molds are removed, and the pipes are placed in the curing room for one day.

Following this initial curing period, the pipes are transferred to the yard to complete the curing process. Throughout this time, samples of the pipes are tested for flexural strength to ensure they meet the Department of Transportation requirements. Donplast ES1000 stands out for its ability to deliver exceptional quality and reliability. Thanks to this admixture, the pipes passed the QC testing done and met the Department of Transportation requirements.

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