## 6 Fresh-State Properties in Cementitious Matrices with RP
### Water Demand  
In the literature, the assessment of water of normal consistency was carried out by a Vicat apparatus as described in BS EN 196-3:2005 [322], GB/T 1346-2011 [310], GB/T 1596-2017 [240], GB 175-2007 [319], and IS:4031-Part 4:2005 [189]. Water demand values reported in the literature are presented in Figure 33.  
As the incorporation of RP increases, water demand increases due to the irregular shape, rough surface, micro pores and the fineness of RP [8; 59; 61; 65; 98; 118; 127; 137; 147; 179; 180; 201; 203; 235; 255; 296; 297; 305]. The multi-edged and rough morphology of RP can lead to an increase in friction between the powder particles. As a result, the water demand for the mixture including PC and RP also increased [98; 179; 255; 297]. In addition, the particle size distribution analysis revealed that the proportion of fine particles was higher in RPs compared to PC. These small particles have a greater capacity to absorb water, resulting in an increased need for water in the paste to produce the desired consistency [65; 98; 179; 255; 297]. Superplasticizers could be involved to decrease the water requirement in the mixtures [44; 132; 147; 201; 298].  
[PERSON] et al. [147] reported that the water demand for cement pastes to achieve standard consistency increases as the content of WCRP increases. However, when FA and SF were added to the cement pastes with WCRP, the presence of FA caused the balling effect, resulting in better fluidity of the pastes and reduced water requirements. [PERSON] et al. [282] observed that the inclusion of steel slag (SS) did not have any impact on the water demand  
Figure 33: Water demand (%) of mechanically grinded RP versus RP percentage (%) [35; 98; 179; 203; 213; 293; 323].  
results, which remained comparable to the reference sample. [PERSON] et al. [254] stated that the addition of nano-silica (NS) to cement results in an increase in water demand.  
Regarding the effect of thermal treatment on the water demand, [PERSON] et al. [247] reported that both untreated and thermally treated RCF have a greater water requirement compared to cement. They observed that when substituting 10% of OPC by mass, RCF-20 primarily functions as a filler, creating nucleation sites for the formation of cement hydration products. However, when the replacement level increases to 20%, the higher water demand of RCF-20 becomes noticeable and has an impact on the development of strength. The RCF-500, which includes dehydrated cement paste including CaO produced during thermal treatment, exhibits a significantly higher water requirement that surpasses the compensatory effects of rehydration reactions.  
Regarding the effect of carbonization treatment on the water demand, [PERSON] et al. [263] reported that the water demand of cement paste typically increases as the replacement level of CRCF increases from 0% to 15%, but no notable variations are observed when the CRCF concentration exceeds 15%. They noted that the inclusion of CRCF typically alters the packing mode of cement particles, potentially affecting the amount of water needed in the pastes. [PERSON] et al. [249] reported that the carbonation of the WCP results in a significant reduction in the porosity of the microstructure of the cement paste, accompanied by the development of calcite crystals. Concurrently, the need for water to produce the appropriate workability decreased as the particle size increased. They recommended utilizing WCP in concrete applications where there is a higher concentration of plasticizer to address the increased water requirement. Furthermore, they recommended employing WCP with GGBS to reduce water demand, as GGBS also imparts a superplasticizer effect in concrete.