This study investigates the innovative integration of Portland limestone cement (PLC) and date palm ash (DPA) in preplaced aggregate concrete (PAC) grouts, addressing the urgent need for sustainable construction materials with a lower carbon footprint. With the construction industry contributing significantly to global CO2 emissions, utilizing agricultural by-products like DPA offers an eco-friendly alternative while mitigating waste disposal challenges. The research evaluates single, binary, and ternary binders incorporating supplementary cementitious materials such as silica fume (SF) and metakaolin to optimize PAC's mechanical properties. Findings reveal that binary grouts with PLC and 10% SF achieved the highest compressive strength (68.3 MPa), outperforming traditional mixtures by 40%. Microstructural analysis confirmed that DPA enhances matrix density and reduces pore size, contributing to improved durability. Recommendations include further exploration of DPA's role in reducing cement content and promoting resource efficiency. The findings highlight PLC and DPA as viable components for greener construction, advancing PAC's potential as a sustainable concrete for structural applications.

This study proposes a novel approach by adding Portland limestone cement (PLC) to preplaced aggregate steel fiber reinforced concrete (PASFRC) to create a sustainable concrete that minimizes CO2 emissions and cement manufacturing energy usage. The method involves injected a flowable grout after premixing and preplacing steel-fibers and aggregates in the formwork. This study evaluates the mechanical properties of a novel sustainable concrete that uses PLC and steel fibers. To achieve the intended objective, long and short end-hooked steel fibers of 1%, 2%, 3%, and 6% were incorporated in PASFRC. Also, Analysis of variance (ANOVA) was used to examine the data. Results indicated that PLC and higher fiber doses increased the mechanical properties of PAC. At 90 days, PASFRC mixtures containing 6% long steel fibers demonstrated superior compressive, tensile, and flexural strengths, registering the highest values of 49.8 MPa, 7.7 MPa, and 10.9 MPa, respectively and differed by 188%, 166%, and 290%, respectively from fiberless PAC. The study confirmed the suitability and effectiveness of using PLC with steel fibers in PAC which significantly improved the mechanical properties of PASFRC. This was verified through analytical analysis and new empirical equations were proposed to predict the mechanical properties of PASFRC.