souici ikram

This study aims to investigate the impact of incorporating mineral wastes (such as fillers and recycled sands) and vegetable wastes (specifically date palm fibers) on the physical, mechanical, and durability characteristics of sand concrete (SC). To formulate various types of concrete, we employed both theoretical and experimental methodologies, utilizing a design of experiments that included full factorial design and mixing design. Models derived from these predictions were employed to assess the influence of different mixing factors and their interactions, with the objective of optimizing the performance of the studied sand concrete.

The results demonstrate that the workability compressive strength at 28 days of sand concretes incorporating recycled concrete fillers and recycled brick (RF and RB) is primarily influenced by the content of RB and the natural limestone filler LF, followed by RF, respectively. Under optimal conditions, all three factors reach their peak values (LF= 20%, RF= 10%, and RB= 70%), leading to maximum workability at 18 cm. When these factors are adjusted to (LF= 10%, RF= 2%, and RB= 88%), the compressive strength at 28 days reaches 35.85 MPa. Conversely, with percentages of (LF= 33.33%, RF= 33.33%, and RB= 33.33%), the workability and compressive strength values are 15.94 cm and 23.87 MPa, respectively. These findings underscore the enhanced compressive strength, attributed to the pozzolanic reaction of RB fines and the formation of new C-S-H, promoting increased densification of the cementitious matrix.

The results from optimizing the length and amount of date palm fibers (DPF) in sand concrete indicate that the rise in compressive strength at 28 days is predominantly influenced by increasing fiber length (FL), followed by decreasing fiber percentage (FP). Conversely, the improvement in flexural strength at 28 days is attributed to the increase in both factors (LF and PF). Overall, the inclusion of DPF in sand concrete plays a substantial role in enhancing flexural strength, although higher fiber content may result in a decrease in compressive strength for these concrete mixes.

The origin of waste materials, particularly mineral waste, notably the condition of the demolished structure, exhibits a robust correlation with the quantity of adherent mortar, significantly influencing the anticipated outcomes. SEM analysis of recycled filler-based sand concrete utilizing SC/FR indicates that RFs contain a higher proportion of fines, rendering the structure of recycled sand concrete less compact compared to the control sand concrete SC 0/0, given that RFs originate from the demolition of previous specimens. Sand concretes utilizing recycled sand (SC/RS) demonstrate compressive strength like SC 0/0, primarily due to the inherent nature of these recycled sands, sourced from freshly manufactured male slabs.