Abstract:
Reducing the amount of cement in construction has become a challenge in the 21st
century. In this study, limestone powder (LSP) is adopted to partially replace cement
at different weight percentages (5%, 10%, 15% and 20%). The influence of LSP on
engineering properties such as workability, compressive strength, splitting tensile
strength, flexural strength and toughness, water permeability, and surface resistivity
is investigated to assess the acceptability of LSP blended concrete and to find the
optimum replacement level considering these properties. At low replacement levels
(5% and 10%), the mechanical and durability properties are improved due to the
nucleation effect of LSP. Beyond 10% replacement, the dilution effect dominates
which disadvantages the concrete. The workability linearly rises with the increase in
the LSP content. The compressive and tensile strength does not vary much from the
control specimen up to a 10% replacement level. The highest compressive and
flexural strength is recorded for 10% LSP replacement. Toughness calculated from
the beam load-deflection curve showed an increased value with increased LSP
replacement. In comparison to the control specimens, 6.4% higher flexural strength
and 90% higher toughness index are achieved for 10% LSP. An equation has been
proposed using a machine learning approach to predict the tensile strength of LSP
blended concrete with 87% accuracy. Water permeability and chloride ion
penetrability are reduced for higher LSP content as LSP works as a filler and
enhances pore structure. This study summarizes that 10% cement substitution with
the LSP can be adopted for overall better mechanical and durability properties of
concrete.
