TITLE:
Investigation of Carbonation of Concrete Based on Crushed Sand and Admixtures
AUTHORS:
Jacques Herve Koung à Bediang, Emmanuel Elat Assoua Moukete, Paul Djomou Djonga, Michel Mbessa
KEYWORDS:
Carbonation, Concrete, Crushed Sand, Sikamant, Water-Repellent
JOURNAL NAME:
Journal of Minerals and Materials Characterization and Engineering,
Vol.12 No.5,
August
26,
2024
ABSTRACT: Carbonation is a natural aging process that occurs in all types of concrete. One of its primary implications is the acceleration of steel corrosion caused by the phenomena of depassivation. The goal of this research is to investigate the carbonation of quarry sand-based concrete. The concrete is made of 100% crushed sand 0/6.3, gravel 8/15, and 15/25 from the Arab Contractor quarry in Nomayos, Cameroon, with CEM II B-P 42.5 R from CIMENCAM (Cimenteries du Cameroun). The study employed two admixtures: one with a dual superplasticizing and reducing action (Sikamen) and another with a water-repellent effect (Sika liquid). Carbonation was performed on concrete samples at the following dates: 0, 7, 14, 28, 56, 90, 180 days, one year, and six months. Carbonated concrete (CC) and non-carbonated concrete (NCC) samples are compared in terms of their physical attributes and mineralogical characteristics. The results of this investigation reveal that after more than a year and six months of carbonation, porosity decreases and permeability increases. Despite the high fineness modulus of quarry sand, the compressive strength of quarry sand-based concrete is satisfactory. Carbonation depth is relatively high on some dates, exceeding the minimal cover value for concrete reinforcement. Sikament additive increases concrete compactness and durability while decreasing permeability. Sika water repellant mixes with the lime in cement to generate complimentary crystallizations that block the mortar’s capillaries, making it watertight.