Ternary Mixes of Self-Compacting Concrete with Fly Ash and Municipal Solid Waste Incinerator Bottom Ash

Abstract

This study aims to evaluate the potential of incorporating fly ash (FA) and municipal solid waste incinerator bottom ash (MIBA) as a partial substitute of cement in the production of self-compacting concrete mixes through an experimental campaign in which four replacement levels (i.e., 10% FA + 20% MIBA, 20% FA + 10% MIBA, 20% FA + 40% MIBA and 40% FA + 20% MIBA, apart from the reference concrete) were considered. Compressive and tensile strengths, Young’s modulus, ultra-sonic pulse velocity, shrinkage, water absorption by immersion, chloride diffusion coefficient and electrical resistivity were evaluated for all concrete mixes. The results showed a considerable decline in both mechanical and durability-related performances of self-compacting concrete with 60% of substitution by MIBA mainly due to the aluminium corrosion chemical reaction. However, workability properties were not significantly affected, exhibiting values similar to those of the control mix.

Binary Mixes of Self-Compacting Concrete with Municipal Solid Waste Incinerator Bottom Ash

“…This led to an increase in porosity of the MIBA-containing SCC in the hardened state, being one of the main factors of strength decline [41][42][43]. This inverse proportionality, between MIBA content and compressive strength, had been reported in the study of Simões et al [14], wherein ternary mixes of SCC were produced with MIBA and FA. The main results showed that the highest percentage of MIBA caused an average compressive strength loss of 74% when compared to the RC.…”

“…Other researchers found a similar decline in performance with increasing replacement levels [11][12][13]. Simões et al [14] used MIBA in combination with fly ash and cement in the production of ternary self-compacting concrete mixes; despite the decline in performance with increasing MIBA content, all mixes demonstrated adequate levels of workability according with existing regulations. Promising results are likely to be observed in mixes with relatively high replacement levels if MIBA is adequately treated before use.…”

“…However, an interesting observation is that at 91 days, the RC has presented a UPV of 4918 m/s, which is more than the UPV known for sound concrete (i.e., 4500 m/s [51]). [14] described the total length of shrinkage in ternary mixes of SCC with FA and MIBA as having rapid initial evolution. In this study, all mixes between 14 to 28 days reached around 50% of their corresponding 91-day shrinkage value.…”

“…Figure7(left) shows the evolution of shrinkage over 91 days. Simões et al[14] described the total length of shrinkage in ternary mixes of SCC with FA and MIBA as having rapid initial evolution. In this study, all mixes between 14 to 28 days reached around 50% of their corresponding 91-day shrinkage value.…”

Durability Evaluation of Calcined Clay and Limestone Powder Blended Ternary Self-Compacting Concrete

“…This is expected because Concretes with blended binder systems exhibit a more refined pore structure than OPC systems because of the additional/prolonged hydraulic and pozzolanic reactions [9]. Other properties that may be improved include strength [10], durability [11], and microstructural properties [12] of SCC.…”