## 6 Fresh-State Properties in Cementitious Matrices with RP  
### Workability  
Workability in the literature was assessed by consistency, fluidity, flowability, slump, and spread tests as per GB/T 50080-2002 [307], GB/T 50081-2002 [308], GB/T 2419-2005 [309], GB/T 1346-2011 [310], GB/T 8077-2012 [311], BS EN 1015-6 [312], EN1015-3:2000 [313], GB/T 17671-2021 [314], ASTM-C1437 [315], ASTM-C230/C230M [316], and ASTM-C143/C143M [317] by using a flow table [59, 65, 82, 179, 180, 204], a slump cone-shaped cylinder [263], and an electric jumping table [98, 118, 130, 194, 318]. Overall, the addition of RP results in a substantial decrease in the workability [45, 52, 62, 65, 72, 84, 97, 98, 116, 119, 129, 145, 152, 179, 201, 229, 235, 250, 255, 294, 295, 318] as presented in Figure 27. In addition, there is an obvious decrease in the workability as the RP fineness increases [45, 152, 204, 295]. The decrease in the workability of the mix can be partially attributable to the porous and uneven microstructure, high specific surface area of fine particles, elevated initial hydration heat in the mixture as a result of the increased RP content, and high-water absorption of RP, resulting in a faster absorption of the required free water for flow [35, 45, 59, 71, 72, 84, 97, 98, 116, 137, 145, 152, 194, 201, 222, 229, 250, 255, 294, 297]. To maintain the workability of RP, pre-wetting, the addition of mixing water, water reduction agent, or superplasticizer, is required for moisture compensation [6, 171, 194, 255]. [PERSON] et al. [98] reported that utilizing RCP at a low concentration (less than 20%) would enhance the fluidity of the mortar. However, at greater substitution levels, such as 30%, the fluidity of the RCP mortars decreased in comparison to the OPC counterparts. [PERSON] et al. [180] observed that, when the replacement ratio of RCP increases, the fluidity of mortars also increases, specifically when the replacement ratio reaches 40%. However, increasing the RCP replacement ratio to 50% has a detrimental impact on fluidity. [PERSON] et al. [179] stated that when comparing the reference mortar with untreated RCP to the one with pre-ground RCP, the fluidity of the latter showed a slight increase. Figure 26: Pore volume fraction (%) versus pore sizes (nm) for nano activated RP utilized in cement-based materials [100, 140, 217]. [PERSON] et al. [35] stated that cement paste's fluidity increases and eventually decreases due to RFP particles' high specific surface area and water absorption. Adding the right quantity of RFP to cement (no more than 30%) makes it more fluid. [PERSON] et al. [152] stated that the geometry of particles seems to have negligible or moderate impact on the fluidity of fresh pastes, but the size distribution plays a significant role. Controversially, [PERSON] et al. [8] reported that as untreated WCP is included, the paste mixture becomes slightly more fluid. This is because WCP has slightly larger particles than cement, which reduces specific surface area and water consumption. [PERSON] and [PERSON] [298] also reported an increase in fluidity with the incorporation of ground waste concrete (GWC). [PERSON] et al. [59] worked with recycled fine particles (RFnPs), recycled medium particles (RMdPs), and recycled coarse particles (RCrPs). They stated that regardless of the w/b of 0.4 or 0.5, a fluidity loss of 9% to 23% was seen when 10% to 30% of the cement was replaced with RFnPs. The inclusion of RCrPs considerably raised the fluidity of cement pastes, but RMdP-containing pastes did not produce any discernible changes in fluidity. An optimal combination of SCMs enhances the workability of the mix [71; 145; 194; 297]. [PERSON] et al. [145] stated that FA and slag greatly enhanced the workability of pastes. [PERSON] et al. [116] reported that the microsphere effect of FA enhances the workability. [PERSON] et al. [139] stated that the results of a flow test demonstrate enhanced workability when FA or GGBS are added with RCF. [PERSON] at el.