NÖTRON ZIRHLAMA UYGULAMALARI İÇİN BORLA ZENGİNLEŞTİRİLMİŞ SÜRDÜRÜLEBİLİR GEOPOLİMERLERİN GELİŞTİRİLMESİ

The growing use of nuclear technologies in energy production, medicine, and radioactive waste management has increased the demand for efficient and low-carbon neutron shielding materials. Although Ordinary Portland cement (OPC)-based concretes are widely used, they exhibit a high carbon footprint and limited compatibility with boron-bearing constituents. This study examines alkali-carbonate-activated, cement-free binders produced using boron mine wastewater (BMWW) as mixing water. A Ca(OH)?–Na?CO?–fly ash (CNF) system was synthesized using two industrial BMWW sources with contrasting chemistries: mildly basic Çamköy (pH ≈ 8.6) and acidic, high-ionic-strength Emet (pH ≈ 3.37). The influence of BMWW chemistry on fresh-state behavior, reaction products, pore structure, environmental safety, and neutron attenuation was evaluated using oscillatory rheology, compressive strength testing, XRD, FT-IR, TGA–DTG, MIP, TCLP, and neutron transmission measurements conducted under narrow-beam geometry with a ²³?Pu–Be source. Binders prepared with Emet BMWW exhibited delayed early structuration but developed a denser alkali-carbonate-activated C–(A)–S–H-type gel network at later ages, resulting in refined porosity and higher compressive strength compared with the tap-water reference. Boron was predominantly incorporated within the amorphous matrix, exhibiting diffusion-controlled release and compliance with TCLP limits. Neutron transmission measurements yielded an effective attenuation coefficient of 0.337 ± 0.01 cm?¹ for the Emet system, approximately 21% higher than the control.