Abstract
Concretes based on alkaliactivated binders have attracted considerable attention as new alternative construction materials, which can substitute Portland Cement (OPC) in several applications. These binders are obtained through the chemical reaction between an alkaline activator and reactive aluminosilicate materials, also named precursors. Commonly used precursors are fly ash (FA), blast furnace slag (GBFS), and metakaolin. The present study evaluated properties such as compressive strength, rate of water absorption (sorptivity), and chloride permeability in two types of alkaliactivated concretes (AAC): FA/GBFS 80/20 and GBFS/OPC 80/20. OPC and GBFS/OPC* concretes without alkaliactivation were used as reference materials. The highest compressive strength was observed in the FA/GBFS concrete, which reported 26,1% greater strength compared to OPC concrete after 28 days of curing. The compressive strength of alkaliactivated FA/GBFS 80/20 and GBFS/OPC 80/20 was 61 MPa and 42 MPa at 360 days of curing, respectively. These AAC showed low permeability to the chloride ion and a reduced water absorption. It is concluded that these materials have suitable properties for various applications in the construction sector.
Highlights
Portland cement, with an annual production of almost 3 Gt, has become a prevalent material in the construction industry (Juenger, Winnefeld, Provis, and Ideker, 2011; Gao, Shen, Shen, Liu, and Chen, 2016)
Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability
The results show that the alkali-activated concretes granulated blast furnace slag (GBFS)/OPC and fly ash (FA)/GBFS, featured lower absorption coefficients (52% and 10%, respectively) compared to 100% OPC
Summary
With an annual production of almost 3 Gt, has become a prevalent material in the construction industry (Juenger, Winnefeld, Provis, and Ideker, 2011; Gao, Shen, Shen, Liu, and Chen, 2016). Alkali-activated concretes based on fly ash and blast furnace slag: Compressive strength, water absorption and chloride permeability. Abubakr, Soliman, and Diab (2020) evaluated the impact performance of the same type of concrete using different modules of activator solution (Ms= SiO2/Na2O ratio) and percentages of Na2O They reported that, in comparison with OPC, alkali-activated systems generally had up to 70% and 40% better compressive and tensile strength, respectively. Compressive strength, rate of water absorption (sorptivity), and chloride permeability of two types of alkaline activated concretes (AAC) produced from blast furnace slag and fly ash were evaluated. The materials used in this study were fly ash (FA), granulated blast furnace slag (GBFS), and Colombian ordinary Portland cement (OPC) for general use. Kg/m3 Cement FA GBFS SS NaOH Fine aggregate Coarse Aggregate L/S ratio Slump (mm)
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