Durability and microstructural behavior of Nano silica-marble dust concrete

Abstract

Present study assesses the durability performance of concrete mix with the addition of marble dust and Nano silica as partial replacement of cement. Concrete blends with 1 %, 2 %, and 3 % Nano silica and 5 %, 10 %, and 15 % marble dust powder were prepared at constant water to binder ratio of 0.4. The bulk density, water permeability, water absorption, carbonation depth, rapid chloride penetration test, and acid attack after curing for 28 days along with mineralogical and morphological tests were carried out. The carbonation depth was investigated after exposing the samples for a long duration of 90 days and 180 days, respectively. The durability tests revealed that the incorporation of Nano silica (2 %) and marble dust (5 %) together, resulting in a decrease in water absorption and permeability up to 26 %, and 57 %, respectively. A reduction of around 20 % in carbonation depth was also observed for concrete mixes containing 2 % Nano silica and 5 % marble dust powder. Nano silica and marble dust containing concrete mixes offer good resistance to acid attack. It was observed that the incorporation of fine particles of marble dust (5 %) and Nano silica (2 %) in cement enhanced the bulk density by reducing the pores inside the matrix and thus improves the overall durability properties of the concrete mix. The utilization of nano silica and marble dust as replacement of cement in concrete can lower the CO2 emission produced during the manufacturing of cement.