## 1 Introduction
In this regard, [PERSON] and [PERSON] [16] propose that accurately determining the initial moisture of the aggregates is essential to ensure the appropriate repeatability of the mixture designed, and in consequence, improve the homogeneity of the strength of the hardened concrete. Thus, it is key to consider the water absorption capacity of each fraction of aggregate to adjust the internal water balance at any point in the manufacturing process. Thus, the objective is to accurately control the effective water volume (W\({}_{\text{ef}}\)) parameter involved in the cement reaction [17]. The concept of effective water volume can be defined as the amount of water available for cement hydration; it is a very important aspect when using recycled aggregates with higher water absorption [16]. Hence, only the mixtures performed with the same W\({}_{\text{ef}}\)/C ratio should really be compared by strength, since their cementitious matrices have been manufactured in the same available water conditions [18]. This accurate control of the \begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline \multirow{2}{*}{**Component**} & \multirow{2}{*}{**Unit Costs**} & \multicolumn{3}{c}{**Dosage Costs per m\({}^{3}\) (EUR)**} & \multicolumn{3}{c}{**\% Cost of Concrete in m\({}^{3}\)**} \\ \cline{3-8}  & & **300 kg** & **350 kg** & **400 kg** & **300 kg** & **350 kg** & **400 kg** \\ \hline Aggregates & EUR 6.5/t & 14.0 & 13.2 & 12.5 & 30.6 & 26.7 & 22.7 \\ Cement & EUR 95/t & 28.5 & 32.3 & 38.0 & 62.3 & 65.4 & 69.2 \\ Water & EUR 5/t & 0.8 & 0.8 & 0.8 & 1.6 & 1.7 & 1.7 \\ Additives & EUR 1.1/kg & 2.5 & 3.0 & 3.5 & 5.5 & 6.1 & 6.4 \\ \hline \multicolumn{8}{c}{TOTAL (EUR/m\({}^{3}\))} & 45.8 & 49.4 & 55.0 & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Average cost of standard concrete mixtures for cement content of 300, 350 and 400 kg/m\({}^{3}\) and proportional cost of each component for the total cost of the concrete batch (date: July 2022). initial moisture of aggregates at the time of manufacture is not always considered and adequately implemented by companies, despite the significant implications in the final strength and variability of the concrete [19], and therefore, in the economic optimization of the manufactured products. In high-tech manufacturing plants, the use of different types of additives is highly common and key in providing some of the specific properties of the concrete [20]. Thus, water-reducer/plasticiser additives are used to obtain a significant reduction in the mixing water volume for the same target consistency of the fresh concrete. Additionally, the use of accelerator additives allows the hardening time to be reduced, which is an essential aspect of the pre-casting activity, since achieving the desired strength early in the process allows the manufacturing process to be optimised by reducing the time during which the moulds are occupied with each batch of specimens. For pre-stressed concrete elements, it is standard to define a strength level of 25 MPa as the minimum compressive strength that allow the pre-stress of the steel bars to be released, such that the manufactured specimens can be managed, leaving the production area free to start a new batch. Thus, reducing the setting time of concrete as much as possible is essential to optimise the manufacturing process for each batch and so improve a company's competitiveness. Moreover, construction and demolition waste (CDW) requires specific treatments, following current regulations [21; 22]. Hence, many pre-casting concrete companies have significant problems in managing concrete waste or non-conforming specimens, leading, consequently, to additional costs for their already tight financial situation. Thus, in an attempt to temporarily avoid such costs, companies accumulate significant amounts of waste specimens in need of adequate management. The average cost of transporting and managing only reinforced concrete can be estimated at EUR 10/t [23], although the managing costs may differ according to the area where a company operates.