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Acid Resistance of Alkali-Activated Natural Pozzolan and Limestone Powder Mortar
The development of sustainable, environmentally friendly alkali-activated binder has emerged as an alternative to ordinary Portland cement. The engineering and durability properties of alkali-activated binder using various precursor combinations have been investigated; however, no study has focused on the impact of high-volume natural pozzolan (NP) on the acid resistance of alkali-activated NP and limestone powder. Therefore, the current study assesses the impact of high-volume natural pozzolan (volcanic ash) on the durability properties of alkali-activated natural pozzolan (NP) and limestone powder (LSP) mortar by immersion in 6% H2SO4 for 365 days. The samples were prepared with different binder ratios using alkaline activators (10 M NaOH(aq) and Na2SO4) combined in a 1:1 ratio and cured at 75 °C. NP was combined with the LSP at three different combinations: NP:LSP = 40:60 (AAN40L60), 50:50 (AAN50L50), and 60:40 (AAN60L40), representing low-volume, balanced, and high-volume binder combinations. Water absorption, weight change, and compressive strength were examined. The microstructural changes were also investigated using FTIR, XRD, and SEM/EDS characterization tools. Visual examination showed insignificant deterioration in the sample with excess natural pozzolan (AAN60L40) after 1 year of acid exposure, and the maximum residual strengths were 20.8 MPa and 6.68 MPa in AAN60L40 and AAN40L60 with mass gain (1.37%) and loss (10.64%), respectively. The high sulfuric acid resistance of AAN60L40 mortar was attributed to the high Ca/Si = 10 within the C-A-S-H and N-A-S-H formed. The low residual strength recorded in AAN40L60 was a result of gypsum formation from an acid attack of calcium-dominated limestone powder. The controlling factor for the resistance of the binder to acid corrosion was the NP/LSP ratio, whose factor below 0.6 caused significant debilitating effects.
Acid Resistance of Alkali-Activated Natural Pozzolan and Limestone Powder Mortar
The development of sustainable, environmentally friendly alkali-activated binder has emerged as an alternative to ordinary Portland cement. The engineering and durability properties of alkali-activated binder using various precursor combinations have been investigated; however, no study has focused on the impact of high-volume natural pozzolan (NP) on the acid resistance of alkali-activated NP and limestone powder. Therefore, the current study assesses the impact of high-volume natural pozzolan (volcanic ash) on the durability properties of alkali-activated natural pozzolan (NP) and limestone powder (LSP) mortar by immersion in 6% H2SO4 for 365 days. The samples were prepared with different binder ratios using alkaline activators (10 M NaOH(aq) and Na2SO4) combined in a 1:1 ratio and cured at 75 °C. NP was combined with the LSP at three different combinations: NP:LSP = 40:60 (AAN40L60), 50:50 (AAN50L50), and 60:40 (AAN60L40), representing low-volume, balanced, and high-volume binder combinations. Water absorption, weight change, and compressive strength were examined. The microstructural changes were also investigated using FTIR, XRD, and SEM/EDS characterization tools. Visual examination showed insignificant deterioration in the sample with excess natural pozzolan (AAN60L40) after 1 year of acid exposure, and the maximum residual strengths were 20.8 MPa and 6.68 MPa in AAN60L40 and AAN40L60 with mass gain (1.37%) and loss (10.64%), respectively. The high sulfuric acid resistance of AAN60L40 mortar was attributed to the high Ca/Si = 10 within the C-A-S-H and N-A-S-H formed. The low residual strength recorded in AAN40L60 was a result of gypsum formation from an acid attack of calcium-dominated limestone powder. The controlling factor for the resistance of the binder to acid corrosion was the NP/LSP ratio, whose factor below 0.6 caused significant debilitating effects.
Acid Resistance of Alkali-Activated Natural Pozzolan and Limestone Powder Mortar
Khaled A. Alawi Al-Sodani (author) / Adeshina A. Adewumi (author) / Mohd Azreen Mohd Ariffin (author) / Babatunde Abiodun Salami (author) / Moruf O. Yusuf (author) / Mohammed Ibrahim (author) / Ali H. AlAteah (author) / Mohammed M. H. Al-Tholaia (author) / Sami M. Ibn Shamsah (author) / Mohammad Ismail (author)
2022
Article (Journal)
Electronic Resource
Unknown
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