Cost-effective and green additives of pozzolanic material derived from the waste of alum sludge for successful replacement of portland cement

Abstract

The major objective of this study was to examine the viability of using 5, 10, or 15 mass% of Activated Alum Sludge waste (AAS) instead of Ordinary Portland Cement (OPC) as a pozzolanic ingredient in concrete. This fundamental inquiry framed the investigation and OPC-AAS-hardened composites were studied to see whether they may benefit from inexpensive nanocomposites in terms of improved physical properties, mechanical strength, and resistance to heat and flame. The investigation set out to see how inexpensive nanocomposite might be put to use and the nanoparticles of CuFe2O4 spinel with an average size of less than 50 nm were successfully manufactured. Many different OPC-AAS-hardened composites benefit from the addition of CuFe2O4 spinel, which increases the composites' resistance to fire and enhances their physicomechanical properties at roughly average curing ages. Synthesized CuFe2O4 spinel was shown to have desirable characteristics by TGA/DTG and XRD. By using these methods, we were able to identify a broad variety of hydration yields, including C–S–Hs, C–A–S–Hs, C–F–S–Hs, and Cu–S–Hs, that enhance the physicomechanical properties and thermal resistivity of OPC-AAS-hardened composites as a whole. The composite material comprising 90% OPC, 10% AAS waste, and 2% CuFe2O4 has several positive economic and environmental outcomes.

Mechanical performance and thermal stability of hardened Portland cement-recycled sludge pastes containing MnFe2O4 nanoparticles

“…The net result of the inclusion NMFs parties is the generation of additional quantities of yields like CSHs, CASH, CAHs, CFH, CFSH, and MnCSH that accumulated inside the available pores within the hardened composite matrix giving a more compact and dense structure 34 , 45 , 51 . Besides, the inclusion of 2% of NMFs induces a slight decline in the BD values, due to the agglomeration effect of NMFs particle as mentioned previously 4 . All these results agreed with the compressive strength test results and will receive further support via the XRD, TGA/DTG, and SEM techniques.…”

“…Figure 8 a indicates that specimens made from mixes B and D (using 5% or 10% RAS, by mass) presented a notably higher BD value (at all curing times) relative to a blank (mix A). This finding is correlated to the formation and accumulation of diverse types of hydrated phases that formed via the pozzolanic interaction between available liberated calcium hydroxide and RAS, creating a denser matrix with high strength 4 . On contrary, the BD values when using 15% RAS (mix D) are lower and/or comparable to a blank.…”

“…As demonstrated from the obtained WA% values, indicated the same trend as TP% values for all tested mixes. Obviously, as the B.D values increase the TP% and the WA% decreases 4 . Clearly, all the obtained results for pore structure analysis (BD.TP, and WA) are correlated with each other and agreed with the compressive strength test results.…”

“…The peak implanted at ~ 70–180 °C is devoted to the deportation of uncombined water and disintegration of the amorphous part of CSHs gel and calcium aluminate hydrates (CAHs), Fig. 15 a,b 4 . The mass loss of this peak after 3 and 7 days of hydration is 6.9%, and 7.2%, respectively.…”

“…Fortunately, recycling some industrial wastes becomes an essential way to the crucial challenges mitigate their risks in the future. So, usage of these wastes in the building industry sector has several returns that mainly reduce landfill area, cost saving, energy saving, environmental protection where the peril for human health is minimized, and saving resources 4 – 6 . In previous and recent studies for numerous researchers, plenty of solid byproducts (industrial wastes or agricultural) have been reused in sustainable construction fields.…”