Borrachero María V, Payá Jordi, Brito Santiago, Segura Yasna Pamela, Soriano Lourdes, Tashima Mauro M, Monzó Jose María
Institute of Concrete Science and Technology (ICITECH), Universitat Politècnica de València, 46022 València, Spain.
Departmento Dengenieria de la Construction, Universidad de Magallanes, Av. Bulnes Nº 01855. C.P., Punta Arenas 6210427, Chile.
Materials (Basel). 2022 May 10;15(10):3437. doi: 10.3390/ma15103437.
Large amounts of waste are derived not only from construction processes, but also the demolition of existing buildings. Such waste occupies large volumes in landfills, which makes its final disposal difficult and expensive. Reusing this waste type is generally limited to being employed as filler material or recycled aggregate in concrete, which limits its valorisation. The present work proposes reusing construction and demolition waste to manufacture alkali-activated cement to improve its sustainability and recovery. Construction and demolition waste (C&DW) from a demolition waste collection plant in Valencia (Spain) was physically and chemically characterised. This residue contained large fractions of concrete, mortar, bricks, and other ceramic materials. X-ray fluorescence (XRF) analysis showed that its chemical composition was mainly CaO, SiO and AlO. X-ray diffraction (XRD) analysis revealed that it presented some crystalline products, and quartz (SiO) and calcite (CaCO) were the main components. Blends of C&DW and blast furnace slag (BFS) were alkali-activated with mixtures of sodium hydroxide and sodium silicate. The corresponding pastes were characterised by techniques such as thermogravimetry and scanning electron microscopy (SEM). The alkali-activated mortars were prepared, and the resulting mortars' compressive strength was determined, which was as high as 58 MPa with the 50% C&DW-50% BFS mixture. This work concluded that it is possible to make new sustainable binders by the alkali activation of C&DW-BFS without using Portland cement.
大量废弃物不仅源自建筑施工过程，还来自现有建筑物的拆除。这类废弃物在垃圾填埋场占据大量空间，这使得其最终处置既困难又昂贵。这种废弃物的再利用通常仅限于用作混凝土中的填充材料或再生骨料，这限制了其价值提升。本研究提出将建筑与拆除废弃物用于制造碱激发水泥，以提高其可持续性和回收率。对西班牙巴伦西亚一家拆除废弃物收集厂的建筑与拆除废弃物（C&DW）进行了物理和化学表征。这种残渣包含大量的混凝土、砂浆、砖块及其他陶瓷材料。X射线荧光（XRF）分析表明，其化学成分主要为CaO、SiO和AlO。X射线衍射（XRD）分析显示，它呈现出一些结晶产物，石英（SiO）和方解石（CaCO）是主要成分。C&DW与高炉矿渣（BFS）的混合物用氢氧化钠和硅酸钠的混合物进行碱激发。通过热重分析和扫描电子显微镜（SEM）等技术对相应的浆体进行了表征。制备了碱激发砂浆，并测定了所得砂浆的抗压强度，50%C&DW - 50%BFS混合物的抗压强度高达58MPa。这项工作得出结论，不使用波特兰水泥，通过对C&DW - BFS进行碱激发来制备新型可持续粘结剂是可行的。
