Evaluation of the Combined Use of Waste Paper Sludge Ash and Nanomaterials on Mechanical Properties and Durability of High Strength Concretes

Abstract

The paper industry burns or buries a significant amount of waste paper sludge. This issue is not suitable from environmental and economic aspects. In this study, the mechanical and durability properties of high-strength concrete containing waste paper sludge ash (WPSA) were evaluated. The variables were WPSA (0, 5, 10, and 15% by weight of cement), silica nanoparticles (0 and 2.5 by weight of cement), and aluminum oxide nanoparticles (0 and 2.5 by weight of cement). Compressive strength, splitting tensile strength, flexural strength, and ultrasonic pulse velocity tests were conducted to evaluate the mechanical properties. The durability properties were also investigated using water penetration depth, water absorption, and electrical resistivity tests. The microstructure of the specimens was analyzed by preparing electron microscopic images. The combined effect of WPSA and nanoparticles on improving the mechanical and durability properties of high-strength concrete are better than using each of them alone. WPSA and nanoparticles react with calcium hydroxide formed due to cement's hydration, and silica produces hydrated calcium, which is the hard material that makes concrete strength. Consumption of calcium hydroxide and production of more hydrated calcium silicate in the presence of nanoparticles and WPSA are among the reasons for water absorption reduction, increased electrical resistance, and water penetration depth reduction in concrete specimens. By replacing part of the cement with WPSA, silica nanoparticles, and aluminum oxide nanoparticles, the transition zone between the aggregates strengthens, and the tensile and flexural strengths increased.

Long-Term Comparison between Waste Paper Fly Ash and Traditional Binder as Hydraulic Road Binder Exposed to Sulfate Concentrations

“…Waste paper ash (WPA), a byproduct of recycling paper, varies in terms of its chemical and physical properties, generally depending on the raw material used during incineration. However, in most cases, WPA contains cementitious properties [ 33 , 34 ] and, to some extent, follows the same pattern as cement. After mixing WPA with water, lime makes the solution alkaline (around 12) [ 35 ].…”

Influence of Various Design Parameters on Compressive Strength of Geopolymer Concrete: A Parametric study by Taguchi Method

“…The environmental issues associated with greenhouse gases, in addition to the depletion of natural resources, play a leading role in the sustainable development of the cement and concrete industry during this century. Due to scarcity of natural resources or growing concern over greenhouse gases or both, a time will come when the production of cement will have to be curtailed or cannot be increased to maintain the ecological balance [4]. Therefore, it is necessary to look for sustainable materials for the production of concrete.…”