Physics Maths Engineering
Hydration, Reactivity and Durability Performance of Low-Grade Calcined Clay-Silica Fume Hybrid Mortar
Kwabena Boakye,
Morteza Khorami
Peer Reviewed
Related Subjects
Abstract
Low-grade calcined clay, due to its low cost, availability and low temperature calcination, has been gaining attention in recent times as a supplementary cementitious material (SCM) in the manufacture of revolutionary building materials to improve the fresh and hardened properties of concrete. Silica fume, on the other hand, has been used, over the years, to improve the performance of concrete due to its reduced porosity and improved transition zone quality. In spite of the individual contribution of these two pozzolans to the strength and durability of concrete, there is a knowledge gap in the properties of ternary blended mixes utilizing calcined clay and silica fume. In this study, the synergistic effect of calcined clay and silica fume on the fresh and hardened properties of cementitious mortar have been investigated. The two pozzolans were used to partially substitute Portland cement to form a ternary blended composite binder having, at a maximum, a replacement of 30% by weight and a varying content of calcined clay and silica fume. The influence of the binary and ternary blended mixes on hydration, pozzolanic reactivity and the mechanical and durability properties of mortar was studied. From the results, partial replacement of cement with 30% calcined clay and silica fume caused significant reductions in the portlandite content of the two hydrated pastes at all curing ages. Drying shrinkage was found to be less severe in the control mortar than the blended cement mixes. Compared to the blended cement specimens, the control suffered the most weight (13.3%) and strength (10%) losses, as indicated by the sulphate resistance test.
1. What role do infrastructures play in urbanization and economic activities?
Infrastructures are fundamental to urban growth and economic operations. However, they are often vulnerable, and the lack of accurate subsurface mapping undermines the sustainability and resilience of these structures.
2. What was the aim of the study presented in the paper?
The study aimed to develop a 3D topographical predictive model using distributed geospatial data and evolutionary gene expression programming (GEP) to model subsurface bedrock topography at a concrete-face rockfill dam (CFRD) in Guilan province.
3. How did the GEP model compare to traditional geostatistical methods?
The GEP model showed 82.53% accuracy, outperforming the traditional ordinary kriging (OK) method, which had an R² of 0.92, with a 9.61% improvement in prediction performance.
4. What is the significance of the generated subsurface model?
The subsurface model offers valuable insights into the stability of structures and hydrogeological properties, which are crucial for determining appropriate foundation designs and improving the safety of infrastructure.
