Partial Replacement of Cement with Waste Paper Sludge Ash

Cement production is one of the sources that emit carbon dioxide, in addition to deforestation and combustion of fossil fuels also leads to ill effects on environment. The global cement industry accounts for 7% of earth’s greenhouse gas emission. To enhance the environmental effects associated with cement manufacturing and to constantly deplore natural resources, we need to develop other binders to make the concrete industry sustainable. This work offers the option to use waste paper sludge ash as a partial replacement of cement for new concrete. In this study cement in partially replaced as 5%, 10%, 15% and 20% by waste paper sludge ash in concrete for M25 mix and tested for compressive strength, tensile strength, water absorption and dry density up to the age of 28days and compared it with conventional concrete, based on the results obtained, it is found that waste paper ash may be used as a cement replacement up to 5% by weight and the particle size is less the 90µm to prevent reduction in workability. Keywords: slump test, Compressive strength, split tensile strength, water absorption test, Waste Paper Sludge Ash Concrete, Workability.

Synthesis of Zeolitic Material with High Cation Exchange Capacity from Paper Sludge Ash Using EDTA

Paper sludge ash (PSA) typically has a low Si abundance and significant Ca content because of the presence of calcite fillers, which interfere with the zeolitic conversion of PSA. Ca-masking with ethylenediaminetetraacetic acid (EDTA) was used to reduce Ca interference during zeolite synthesis so that a zeolitic product with a high cation exchange capacity (CEC) could be synthesized. Hydroxysodalite, zeolite-P, hydroxycancrinite, tobermorite, and zeolite-A can be synthesized from PSA by an alkali reaction with EDTA. With the addition of EDTA, calcium ions in the solution were trapped by chelation, and the number of zeolitic crystals with low Si/Al (Si/Al = 1), zeolite-A, increased owing to the promotion of the synthesis reaction. A product with a high CEC that has a high zeolite-A content was obtained. The chelating agent can inhibit Ca interference for zeolite synthesis by Ca-masking, and a product with a high zeolite-A content can be obtained from PSA using EDTA.

Enhancement of High Strength Concrete Performance By Utilising Nano Waste Paper Sludge Ash

High strength concrete (HSC) is an amazing breakthrough in the history of construction material. Due to its high strength, durability, and economic value, it has been used in large-scale construction with a unique structure design not achievable by conventional concrete. However, HSC uses a high amount of cement powder which contributes to its overall strength. However, it will require high cement consumption and increases carbon dioxide emission. Waste paper sludge ash (WPSA) is utilised in cement and has improved concrete properties. Nano engineered WPSA might further enhance HSC capabilities. This research focused on the physical and fresh properties of HSC with partial replacement of nano-engineered WPSA to cement through experimental investigation. The HSC produced in this research has a targeted strength of more than 40MPa with a fixed water-cement ratio of 0.2. The WPSA was oven-dried and was sieved to a particle size of 212 micrometers. Then, it was milled until a nano-size particle is obtained. The nano WPSA is used to replace cement in the HSC mix with a replacement percentage of 1%, 3%, 5%, 7%, and 10%. The new properties of the concrete were measured by conducting the flow table test, and the physical property was determined by conducting the compressive test. Compressive tests were conducted for 1, 3, 7, 14, and 28 days with a cube sample size of 50mm x 50mm x 50mm. This research shows that 1% of nano WPSA replacement tends to improve the compressive strength of the HSC concrete by 10.7% compared to the control sample. On the other hand, the 1% replacement of nano WPSA in HSC did not affect the concrete's workability compared to the control sample. The conventional HSC properties were improved with less usage of cement with the use of WPSA.