## 1 Introduction  
Cement is the most widely consumed material in construction, and its production significantly impacts the environment due to high energy consumption [1, 2]. The production of cement generates 630 kg of CO\({}_{2}\) per ton accounting for 8% of global CO\({}_{2}\) emissions. This is not a result of the fuel burned during its production processing but also due to the decomposition of limestone [3]. Global temperatures have increased by an average of 0.6 \({}^{\circ}\)C over the past in the last century, and it is predicted to rise by 1.4-5.8 \({}^{\circ}\)C in the present century. To address global warming and prevent climate change, several studies have been carried out to replace cement with other materials. Several materials have been used as a cement replacements, including Egyptian cornstalk ash, used by [PERSON] et al. [4]; rock dust, used by [PERSON] et al. [5]; coal bottom ash, used by [PERSON] et al. [6]; sewage sludge ash, used by [PERSON] and [PERSON] [7]; waste glass powder [8; 9]; and silica fume [10]. Other studies have examined on the influence of ceramic waste powder on the shear performance of environmentally friendly reinforced concrete beams [11], the properties and structure of functional concrete mixtures modified with river shell powder [12], and the flexural behavior of reinforced concrete beams incorporating waste marble powder for sustainable concrete applications [13]. In Chile, seashells are an abundant waste material that has been proposed as a substitute for conventional materials, such as cement, sand, and coarse aggregate in construction [14]. The main component of the seashells is calcium carbonate (CaCO\({}_{3}\)) mainly in the form calcite; their chemical composition is predominantly calcium oxide (CaO) varying between 48% and 87.2% for oyster, mussel, cockle, and clam shells, with small amounts of other oxides are also present [14]. The microstructure observed in powdered clam, mussel, oyster, and cockle shells reveals irregularly shaped particles, multi-angled shapes, thin particles, and needle-like particles with sizes ranging from 13.6 \(\upmu\)m to 29.9 \(\upmu\)m [15]. The impurity levels ranged from 0.014 to 0.51% for chloride ion content and from 0.27 to 2.15% organic matter, exceeding the limits set by the Chilean Standard (NCh170) for chloride content. These limits are 0.25 kg (CI-)/m\({}^{3}\) for prestressed concrete and 1.20 kg (CI-)/m\({}^{3}\) for reinforced concrete [16]. However, these values can be reduced through a calcination process [17]. Given the salinity content (35%) of seashells present, [18; 19] suggest using them as a substitute for up to 10-20% of concrete aggregate. Seashells have been used as both coarse and fine aggregates, with sizes ranging from 0.074 to 9.5 mm [15; 18; 20]. In the case of fine aggregates, increased friction among particles has been observed, resulting in reduced workability, as presented by [PERSON] et al. [21]. However, this can be improved by using additives, as presented by [PERSON] et al. [22], or by increasing the aggregate substitution up to 20%, as presented by [PERSON] et al. [23]. On the other hand, particle size does not significantly affect the setting time, as presented by [PERSON] et al. [22], although slower curing has been reported. This could be mitigated by increasing the replacement level up to 20% when fine aggregate is used [15; 23; 24]. In terms of the mechanical properties, the compressive strength is negatively im-pacted by an increase in the amount of shell aggregate. Replacing more than 20% of mussel shells led to 63% decrease [25], while substituting over 50% of the oyster shells resulted in a 46% decrease [15]. In contrast, an increase of over 14% in compressive strength was observed when the oyster shell was replaced 15% of the lime [26]. Addi-tionally, a 5% increase was noted when the oyster shell was used to replace 5% of the cement [18]. Similarly, tensile strength was influenced by the inclusion of marine shells was from 10 to 30% [27; 28; 29].