Van den Heede Philip, Ringoot Niels, Beirnaert Arno, Van Brecht Andres, Van den Brande Erwin, De Schutter Geert, De Belie Nele
Magnel Laboratory for Concrete Research, Ghent University, Technologiepark Zwijnaarde 904, Ghent B-9052, Belgium.
Indaver nv, Dijle 17a, Mechelen B-2800, Belgium.
Materials (Basel). 2015 Dec 25;9(1):9. doi: 10.3390/ma9010009.
Nowadays, more efforts towards sustainability are required from the concrete industry. Replacing traditional aggregates by recycled bottom ash (BA) from municipal solid waste incineration can contribute to this goal. Until now, only partial replacement has been considered to keep the concrete workability, strength and durability under control. In this research, the feasibility of a full aggregate replacement was investigated for producing prefabricated Lego bricks. It was found that the required compressive strength class for this purpose (C20/25) could be achieved. Nevertheless, a thorough understanding of the BA properties is needed to overcome other issues. As BA is highly absorptive, the concrete's water demand is high. This workability issue can be dealt with by subjecting the fine BA fraction to a crushing operation to eliminate the porous elements and by pre-wetting the fine and coarse BA fractions in a controlled manner. In addition, a reactive NaOH washing is needed to avoid formation of longitudinal voids and the resulting expansion due to the metallic aluminum present in the BA. Regarding the long-term behavior, heavy metal leaching and freeze-thaw exposure are not problematic, though there is susceptibility to acetic and lactic acid attack and maybe increased sensitivity to alkali-silica reaction.
如今，混凝土行业需要在可持续发展方面做出更多努力。用城市固体废物焚烧产生的再生底灰（BA）替代传统骨料有助于实现这一目标。到目前为止，为了控制混凝土的工作性、强度和耐久性，仅考虑了部分替代。在本研究中，对生产预制乐高积木砖进行全骨料替代的可行性进行了研究。结果发现，可以达到为此目的所需的抗压强度等级（C20/25）。然而，需要深入了解BA的特性以克服其他问题。由于BA具有高吸水性，混凝土的需水量很高。这个工作性问题可以通过对细BA部分进行破碎操作以消除多孔元素，并以可控方式对细BA和粗BA部分进行预湿来解决。此外，需要进行活性NaOH洗涤以避免形成纵向孔隙以及由于BA中存在的金属铝而导致的膨胀。关于长期性能，重金属浸出和冻融暴露没有问题，尽管易受乙酸和乳酸侵蚀，并且可能对碱-硅酸反应的敏感性增加。
