Abstract

Recycling and utilization of waste concrete and industrial waste slags is a significant step towards the protection of the environment and sustainable development. Industrial waste slags including ferronickel (Greece) and fayalite (Finland) slags were mixed with ground waste concrete for the production of inorganic polymers (IPs). The effects of different parameters during alkaline activation such as solution concentration (6 to 12 M NaOH), curing temperature (60 to 80 °C), and aging period (7 to 28 days) upon the uniaxial compressive strength of the produced specimens were determined. The optimum conditions for ground concrete waste-based inorganic polymers were found to be the use of alkali activator with mass ratio of Na₂SiO₃ to NaOH 1 and L/S 0.3 cured at 80 °C for 24 h and aged for 7 days with compressive strength of 16 MPa. Molar ratios of \(\frac{{{\text{SiO}}_{2} }}{{{\text{Al}}_{2} {\text{O}}_{3} }}\) and \(\frac{{{\text{H}}_{2} {\text{O}}}}{{{\text{Na}}_{2} {\text{O}} + {\text{K}}_{2} {\text{O}}}}\) in the reactive paste were 16.03 and 13.02, respectively. IPs produced from ground concrete waste (GWC), fayalitic (FS), and ferronickel (LS) slag mixtures; in particular, a mix ratio of 25GWC-25FS-50LS (Na₂SiO₃ to NaOH 1 and L/S 0.2, cured at 60 °C for 24 h and aged for 7 days) obtained high compressive strength (47 MPa). Molar ratios of \(\frac{{{\text{SiO}}_{2} }}{{{\text{Al}}_{2} {\text{O}}_{3} }}\) and \(\frac{{{\text{H}}_{2} {\text{O}}}}{{{\text{Na}}_{2} {\text{O}} + {\text{K}}_{2} {\text{O}}}}\) in the reactive paste were 9.59 and 16.81, respectively. Structural integrity of selected IPs (25GWC-25FS-50LS) was observed when immersed in acidic H₂SO₄ and salt Na₂SO₄ solutions of 0.5 M and/or subjected to high-temperature firing (up to 400 °C).

Graphical Abstract

中文翻译：

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利用工业废渣增强地面废混凝土基无机聚合物

摘要

废混凝土和工业废渣的回收利用是朝着环境保护和可持续发展迈出的重要一步。将工业废渣（包括镍铁（希腊）和方铁石（芬兰））与碎废混凝土混合，以生产无机聚合物（IP）。确定了在碱活化过程中不同参数（例如溶液浓度（6至12 M NaOH），固化温度（60至80°C）和老化时间（7至28天））对所制备试样的单轴抗压强度的影响。 。发现用于地面混凝土废料的无机聚合物的最佳条件是使用质量比为Na ₂ SiO ₃的碱活化剂。于NaOH 1和L / S 0.3的混合物在80°C下固化24 h并老化7天，抗压强度为16 MPa。摩尔比\（\ frac {{{\ text {SiO}} _ {2}}} {{{\ text {Al}} _ {2} {\ text {O}} _ {3}}} \）和\（\ frac {{{\ text {H}} _ {2} {\ text {O}}}} {{{\ text {Na}} _ {2} {\ text {O}} + {\反应性粘贴中的text {K}} _ {2} {\ text {O}}}} \）分别为16.03和13.02。由地面混凝土废物（GWC），铁矾（FS）和镍铁（LS）矿渣混合物生产的IP；特别地，以25GWC-25FS-50LS的混合比（Na ₂ SiO ₃与NaOH 1和L / S 0.2，在60℃下固化24小时并老化7天）获得高抗压强度（47MPa）。摩尔比\（\ frac {{{\ text {SiO}} _ {2}}} {{{\ text {Al}} _ {2} {\ text {O}} _ {3}}} \）和\（\ frac {{{\ text {H}} _ {2} {\ text {O}}}} {{{\ text {Na}} _ {2} {\ text {O}} + {\ text反应性粘贴中的{K}} _ {2} {\ text {O}}}} \）分别为9.59和16.81。当浸入0.5 M的酸性H ₂ SO ₄和盐Na ₂ SO ₄溶液中和/或经受高温烧制（最高400°C）时，观察到所选IP（25GWC-25FS-50LS）的结构完整性。

图形概要