Fresh-state Properties of Self-compacting Mortar and Concrete with Combined Use of Limestone Filler and Fly Ash

Abstract

This paper presents the results of a study on the behaviour of self-compacting concrete (SCC) in the fresh and hardened states, produced with binary and ternary mixes of fly ash (FA) and limestone filler (LF), using the method proposed by Nepomuceno. His method determines the SCC composition parameters in the mortar phase (self-compacting mortar -SCM) easily and efficiently, whilst guaranteeing the SCC properties in both the fresh and hardened states. For this, 11 SCMs were studied: one with cement (C) only; three with FA at 30%, 60% and 70% C substitution; three with LF at 30%, 60% and 70% C substitution; four with FA + LF in combinations of 10-20%, 20-10%, 20-40% and 40-20% C substitution. Once the composition of these mortars was defined, 18 SCC mixes were produced: 14 binary SCC mixes were produced with the seven binary mortar mixes, and four ternary SCC mixes were produced with the four ternary mortar mixes. In addition to the methodology proposed by Nepomuceno, the combined use of FA and LF in ternary mixtures was tested. The results confirmed that the method could yield SCC with adequate properties in both the fresh and hardened states. It was also possible to determine the SCC composition parameters in the mortar phase (self-compacting mortar -SCM) that will guarantee the SCC properties in both the fresh and hardened states, as confirmed through the optimized behaviour of the SCC in the fresh state and the promising results in the hardened state (compressive strength). The potential demonstrated by the joint use of LF and FA through the synergetic interaction of both additions is emphasized.

Mechanical and durability properties of self‐compacting mortars containing binary and ternary mixes of fly ash and silica fume

“…FA mixes among all binary and ternary SCMs mixes show the worst compressive strength performance. In the literature, many authors have reported that replacement of FA slows down hardening at early age . It was also stated that calcium in the FA behaves as a pollutant, reduce the mechanical strength and form hydrate assemblages that slow the reaction rate.…”

“…In the literature, many authors have reported that replacement of FA slows down hardening at early age. 17,37,38 It was also stated that calcium in the FA behaves as a pollutant, reduce the mechanical strength and form hydrate assemblages that slow the reaction rate 39 . It can be seen that FA causes significant declines in compressive strength aged 28 days compared to control mix but at 180 days similar strength performance can be observed at FA content of 5-15%.…”

Experimental study of the mechanical properties and durability of self-compacting mortars with nano materials (SiO2 and TiO2)

“…As found out by various authors [13,[27][28][29][30][31], the mixing procedure has a significant influence on the self-compacting mortars fresh-state properties, namely on the optimization of the use of superplasticizers. They confirmed that the mixing time until the superplasticizer is added is not irrelevant to its efficiency and consequently it alters the self-compatibility conditions of these mortars.…”

“…However, it is stressed that the objective in terms of spread and mini V-funnel test results was simply to comply with the workability parameters defined in the reference documents [13,[27][28][29][30][31], in order to reach self-compatibility, which was successfully done for all the mixes produced. Table 4 and Fig.…”

Fresh State Properties of Self-compacting Concrete with Recycled Aggregates - A Literature Review

“…The main difference between SCC, with or without RA, and conventional concrete (CC) is their workability characteristics that allow them to completely fill the moulds, even in densely reinforced elements, with no flocculation, exudation or segregation, solely under their own weight and with no resort to compaction methods (Silva and de Brito, 2015).…”