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CONCRETE PIPES AND MANHOLES114 CPI %u2013 Concrete Plant International %u2013 5 | 2025 www.cpi-worldwide.comwater content, 100% reCO2ver material resulted in higher granularity and lower compactability (absorption, surface).The concrete design was adapted by gradually increasing the water content. At a 14 l/m%u00b3 higher suction water content, comparable granularity and compactability (Fig. 4) as well as the usual flank appearance of the pipes (Fig. 5) were achieved with the 100% reCO2ver material. The hardened concrete results (compressive strength) were comparable to the original composition and demonstrate that the higher water content in the fresh concrete is not available for the formation of capillary porosity. Accordingly, unchanged durability can be assumed.Test production of reinforced-concrete pipes with 100% RC aggregateThe convincing laboratory results enabled the targeted test production of new pipes at the R%u00f6ser II site in Krauchenwies. Under the supervision of all those involved, the natural aggregates in the production of reinforced-concrete pipes DN 500 was replaced 100% with reCO2ver material. No irregularities were observed, neither from a production nor from a visual perspective. Therefore, another mix was produced, this time with 20% less cement. Here, too, no irregularities were observed. The usual grinding work on the spigot end also produced the usual pattern. Finally, the pipe, with 100% reCO2ver aggregate was subjected to the standard crown compression test by the quality assurance authority. Both the requirements of DIN V 1201 and the increased quality requirements of the Federal Association of Concrete Sewer Systems (FBS) were met. The test production demonstrates that the use of 100% RC aggregates processed using the reCO2ver-process is feasible. Further studies, particularly regarding durability, are needed for regular industrial application.Fig. 4: Laboratory results of granularity and compactability.Fig. 5: Comparison of fresh cylinders of the original pipe concrete with the selected concrete concept made of r reCO2ver material with indication of the additional water.%u00a9 Sika Deutschland CH AG & Co KG %u00a9 Sika Deutschland CH AG & Co KG