Properties and activation modification of eco-friendly cementitious materials incorporating high-volume hydrated cement powder from construction waste

The effect of recycled concrete powder (RCP) from precast concrete plant on fresh and mechanical properties of cementitious pastes

“…On the other hand, the R 2 of the linear model was close to 0.90 for the RCP-C mixes, presenting a lower fit to the flow curves. Similar to the results of the mini slump tests, it is observed that the use of RCP-C reduced the flowability of the paste, which is attributed to the fine-ness, irregular morphology, and SSA of the RCP-C (51)(52)(53). In this sense, the irregular shape and the increased water demand (higher SSA) made the flow of particles difficult (higher friction), increasing τ 0 and μ, results also reported by Ge et al ( 54…”

“…Since no superplasticizer was used, the fresh state behavior is solely due to the replacement of Portland cement by RCP-C. As the amount of RCP-C increased, the flowability of the pastes considerably decreased, with the spread area decreasing from 41.16 (reference) to 21.15 cm 2 (C30), a maximum reduction of 48.62%. This behavior is attributed to the fine particles (Figure 4a) and the increase in SSA (requiring more water), the latter caused by the rough surface of RCP-C (Figure 4b) (51)(52)(53). Although there is a 48.52% reduction in the spread in the C30 paste compared to the ref-erence, all the paste were fluid enough not to require mechanical or manual compaction.…”

“…The reduction of compressive strength can be attributed to the dilution effect. The lower amount of clinker translates into a decrease in hydration products, resulting in a less compact microstructure (9,23,31,53). This reduction can be also explained by the inert particles in RCP-C (45,52,59).…”

Assessment of Properties and Microstructure of Concrete with Cotton Textile Waste and Crushed Bricks

“…The substitution of cement with brick powder resulted in decreased early compressive strength. Adding powders from construction and demolition wastes decreases the workability of the concrete mixture because of the high water demand for waste [21,22]. Sai Rahul et al [23] observed that crushed bricks may be used as substituents of fine aggregates (between 150 µm and 4.75 mm) up to 75% and aggregates <150 µm limited to 10%, in paver blocks.…”

“…Materials 2023, 16, x FOR PEER REVIEW 3 of 18 mixture because of the high water demand for waste [21,22]. Sai Rahul et al [23] observed that crushed bricks may be used as substituents of fine aggregates (between 150 µm and 4.75 mm) up to 75% and aggregates <150 µm limited to 10%, in paver blocks.…”