Influence of superplasticizers on the course of Portland cement hydration

Abstract

A multicell isoperibolic — semiadiabatic calorimeter was used for the measurement of temperature and the determination of the hydration heat evolution at earlier period of cement pastes setting and hardening. The measurements were aimed at the determination of the effect of superplasticizers (SPs) on the course of the Portland cement hydration. Commercial polycarboxylate SP was added to the mixtures and the heat effect was measured. With the increasing content of SP, the hydration temperature increased up to a certain value and then decreased. In case of a sufficient amount of water in the mixture to achieve complete hydration of cement, samples with the highest values of the maximum hydration temperature reached the highest values of the released total heat. If there is not a sufficient amount of water to achieve complete hydration, the samples with the highest values of the maximum hydration temperature reach the lowest values of the released total heat.

New additions for eco-efficient cement design. Impact on calorimetric behaviour and comparison of test methods

“…These findings further confirmed the retarding effect of superplasticisers on peak heat of hydration, while a small rise in the total heat released was also observed in the materials containing the admixture. That dual effect was consistent with previous reports [45].…”

“…Figure 4b provides further evidence of the effect of the superplasticiser, which in this case played a dual role, retarding the temperature peak and raising its value. This trend was consistent with reports by Siler [45], who analysed the effect of superplasticisers on heat of hydration determined with Langavant's semi-adiabatic method. Figure 5 plots peak temperature and the time the peak was recorded against CDW and SW replacement ratios, with and without the superplasticiser.…”

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.…”

“…The interaction of cement and chemical admixtures have been studied by atomic force microscopy [69][70][71][72][73], zeta potential [71,70,74,75], small-angle neutron and X-ray scattering [76], calorimetry [77,73,78], in situ synchrotron X-ray diffraction [79], adsorption tests [80,81,73,70], X-ray photoelectron spectroscopy [82], and small-angle X-ray scattering analysis [83].…”

Possibilities of Use of Isothermal and Isoperibolic Calorimetry to Study the Effect of Zinc on Hydration of Cement Blended with Fly Ash

“…Isoperibolic calorimetry is a method which is often used for the monitoring of hydration of hydraulic binders, especialy cements [16,[24][25][26]. The principle is the measurement of temperature changes during hydration at constant ambient temperature.…”