Page 138 - Demo

CONCRETE PIPES AND MANHOLES136 CPI %u2013 Concrete Plant International %u2013 5 | 2025 www.cpi-worldwide.comwith the recycled aggregates cleaned with the reCO2ver process was tested at constant water content. Cylinders were produced in the ICT250 gyratory compactor to the same compaction pore content, and the required number of compaction cycles were determined. In parallel, the granularity (%u201cflowability%u201d of the fresh, uncompacted, semi-dry concrete needed for good mold filling properties) was determined using the %u201cgranularity test%u201d developed by Sika. At the same water 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, 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