Dispersion of CaCO3 nanoparticles by sonication and surfactant treatment for application in fly ash–cement systems

Abstract

This research aims to offset the negative effects of fly ash on the early-age properties of cementitious materials with the use of calcium carbonate (CaCO 3) nanoparticles. The main focus is to enhance the effect of the nanoparticles by improving dispersion through ultrasonication and use of surfactants. CaCO 3 aqueous suspensions with various surfactant types and concentrations are prepared and subjected to different sonication protocols (varying duration and amplitude). Dispersion and stability are quantitatively measured by comparing their absorbance spectra through spectrophotometry and qualitatively evaluated through SEM imaging. The effectiveness of sonicated CaCO 3 nanoparticle additions in accelerating setting and improving early-age compressive strength gain of fly ash-cement pastes is investigated. The sonication protocol is optimized and the most effective dispersion is achieved with polycarboxylate-based superplasticizer. Good agreement is found between the dispersion measurements and mechanical performance.

Advances in understanding hydration of Portland cement

“…With the goal of reducing the percentage of clinker in blended Portland cements, there has been intensive research to study the interaction of superplasticizers with limestone [92][93][94][95][96]70], fly ash [93,[97][98][99][100], silica fume [101,95,102,103] slag [104,78,105], nanosilica [106,100,[107][108][109], and metakaolin [105]. Recently, Burgos-Montes et al [110] studied the compatibility between superplasticizer admixtures and cements with mineral additions.…”

Effects of nano-silica and nano-limestone on flowability and mechanical properties of ultra-high-performance concrete matrix

“…In Table 3, the mixtures are labeled with respect to their dosage: NS#-NC#, For example, NS1.0-NC3.0 represents a mixture with 1.0% nano-SiO 2 and 3.0% nano-CaCO 3 , together partially replacing 4.0% of cement by mass. Before mixing the UHPC matrix, NS and NC particles were dispersed in the mixing water using the ultrasonic dispersion method proposed by Kawashima et al [29]. Mixing procedures were carried out in a rotary mixer according to the method presented in a previous works [30,31].…”

Bioderived “Green” Composite from Soy Protein and Eggshell Nanopowder

“…In this study, anionic dispersant 'PAANa' was chosen for its exceptional dispersion stability for calcium carbonate 32,33. Cationic surfactant was not chosen as they have been found to flocculate calcium carbonate.…”