Abstract
Concrete production is one of the largest consumers of natural non-metallic materials. To mitigate the environmental impact associated with cement production The use of wastepaper sludge ash (WSA) from paper recycling is a new promising direction for saving fuel, energy, and natural resources in cement and concrete production, aimed at reducing the proportion of clinker in cement by replacing part of the cement with supplementary cementitious materials. This approach aligns with the priority principles of uniform and sustainable industry development aimed at creating environmentally friendly, low-energy-consuming technologies. This study is dedicated to investigating the properties of composite systems with different proportions of blast furnace granulated slag and wastepaper sludge ash. Test results show that samples with 70% WSA achieve the highest early strength (2.23 MPa flexural, 7.6 MPa compressive). Later, samples with a 70:30 BFS:TAW ratio exhibit the highest strength (38.3 MPa compressive, 4.6 MPa flexural) due to predominant hydro silicate hydration. The composite system forms CSH(B) hydro silicates and calcium hydro aluminate C4AH13, reacting with WSA gypsum to form calcium hydro sulpho aluminate C3A∙3CaSO4∙32H2O during initial hydration.
Publisher
Lviv Polytechnic National University