Govedarica Ognjen, Aškrabić Marina, Hadnađev-Kostić Milica, Vulić Tatjana, Lekić Branislava, Rajaković-Ognjanović Vladana, Zakić Dimitrije
Faculty of Civil Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Beograd, Serbia.
Department of Basic Engineering Disciplines, Faculty of Technology, University of Novi Sad, 21000 Novi Sad, Serbia.
Materials (Basel). 2022 Jul 14;15(14):4919. doi: 10.3390/ma15144919.
Waste and recycled materials have recently been used in the construction industry to comply with the principles of circular economy and sustainable development. The aim of this paper is to examine the potentials of solidified wastewater treatment sludge (SWWTS) as a supplementary cementitious material (SCM) in the production of lightweight pervious concrete pavers (LWPCP) suitable for pedestrian trails and rooftops (green) that comply with EU standards. Detailed characterization of SWWTS was performed, in order to understand its properties related to application as SCM, which led to the conclusion that it may be applied only as a filler, having 89.5% of Ca(OH). After thorough characterization, LWPCP samples were prepared and testing of physical and mechanical properties was conducted. The research showed that partial replacement of cement with SWWTS led to the decrease of all mechanical properties, ranging between 3.91 and 5.81 MPa for compressive strength and 0.97 to 1.23 MPa for flexural strength. However, all of the investigated mixtures showed a value higher than 3.5 MPa, which was defined as the lowest compressive strength in the range of pervious concrete properties. The addition of SWWTS led to a slight decrease in bulk density of the mixtures and an increase in water absorption. This could be explained by the reduction in hydration products that would fill in the micropores of the matrix, since SWWTS showed no pozzolanic reactivity. Pore sizes that prevail in the tested binder matrices are in accordance with the results measured on ordinary pervious concrete (the largest fraction of pores had a diameter between 0.02 and 0.2 μm). Low thermal conductivity nominates produced pavers as potential rooftop elements.
近期，废弃物和回收材料已被应用于建筑行业，以符合循环经济和可持续发展的原则。本文旨在研究固化污水处理污泥（SWWTS）作为辅助胶凝材料（SCM），用于生产符合欧盟标准的、适用于人行步道和屋顶（绿色）的轻质透水混凝土砖（LWPCP）的潜力。对SWWTS进行了详细表征，以了解其与作为SCM应用相关的性能，结果表明它仅可作为填料使用，其中Ca(OH)含量为89.5%。经过全面表征后，制备了LWPCP样品并对其物理和力学性能进行了测试。研究表明，用SWWTS部分替代水泥会导致所有力学性能下降，抗压强度在3.91至5.81MPa之间，抗折强度在0.97至1.23MPa之间。然而，所有研究的混合物的抗压强度值均高于3.5MPa，这被定义为透水混凝土性能范围内的最低抗压强度。添加SWWTS导致混合物的堆积密度略有下降，吸水率增加。这可以通过填充基体微孔的水化产物减少来解释，因为SWWTS没有火山灰活性。测试的粘结剂基体中占主导的孔径与普通透水混凝土的测量结果一致（最大孔径部分的直径在0.02至0.2μm之间）。低导热系数表明所生产的砖具有作为潜在屋顶材料的特性。
