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Abstract
Thermogravimetric (TG) analysis was applied to the characterisation of the pozzolanic reaction in mortars containing the supplementary cementitious materials (SCMs) pitchstone fines (PF) and fly ash (FA) as partial replacements for Portland cement (PC). TG analysis was used to determine the proportion of calcium hydroxide (CH) present from the hydration of the PC based on the dehydroxylation of the CH present in the blended PC-SCM mortars. The consumption of CH indicated that both SCMs underwent the pozzolanic reaction and that PF was found to compare favourably in its pozzolanic reactivity of FA, the industry and globally accepted standard artificial pozzolan.
as in control specimens. Such results lead to an important conclusion that, the thermal resistance found in specimens containing V was due to its insulation character rather than its pozzolanic reactivity. However, at 600 and 800 °C, in XRD of A2, new
Summary
The pozzolanic reactivity of thermally treated zeolites was studied on the basis of the Chapelle test combined with X-ray diffraction (XRD) and Fourier Transform (FTIR) spectroscopy, as well as thermogravimetric analysis (TG/DTG) and differential thermal analysis (DTA). The raw zeolite samples are from the Pentalofos area, Thrace, NE Greece. Their main mineral constituent is 'heulandite type-II', an intermediate type of the heulandite-clinoptilolite isomorphous series. Calcination of the samples was carried out up to 400, 500, 600, 700 and 1000C for 15 h. The changes were recorded using the above methods. The deformation of the zeolite crystal lattice starts at about 400C and proceeds as the temperature of thermal treatment rises. The thermal treatment of zeolite at 400C improves its pozzolanic reactivity and accelerates the reaction with Ca(OH)2.
The aim of this paper is to verify activity index (pozzolanic reactivity) of finegrained waste glass and clay brick. First part of this work consists from milling process with variation in milling parameters (time, grinding ratio) and determination (analysis) of the grain size distribution. Subsequently strength activity index is assessed for samples of particles size 50-60 μm. According to EN 450-1 method, tested samples does not reached an appropriate limit values as 25% substitute of cement. This result does not disqualify this type of construction and demolition waste as active additive in building materials but it is necessary improving their input parameters.
glass particles with sizes below 300 μm, an ASR gel is less likely to be produced than with aggregate-sized particles, while particle sizes below 75 μm often demonstrate a pozzolanic reactivity according to the literature [ 10 , 13 , 18 ]. This general
, Gonçalves , JP , Cartledge , FK , Toledo Filho , RD , Dweck , J . Evaluation of metakaolin pozzolanic reactivity in cement pastes . Mater Sci Forum . 2008 ; 591–593 : 827 – 832 . 10.4028/www.scientific.net/MSF.591
, “ Pozzolanic reactivity and the influence of rice husk ash on early-age autogenous shrinkage of concrete ,” Front. Mater. , vol. 6 , pp. 1 – 13 , 2019 . 10.3389/fmats.2019.00150 [12
Early stages hydration of high initial strength Portland cement
Part I. thermogravimetric analysis on calcined mass basis
, Ray , AS , Guerbois , J-P , Joyce , P , Haggman , J 2009 Pozzolanic reactivity of the supplementary cementitious material pitchstone fines by thermogravimetric analysis . J Therm Anal Calorim 97 1 71 – 76 10.1007/s10973
reduced due to its lesser pozzolanic reactivity at later ages. The elastic modulus of the concrete is not much dependent on the percentage of SF as no significant variation was observed. The shrinkage of the concrete increases with the increase in the
. Pozzolanic reactivity of the supplementary cementitious material pitchstone fines by thermogravimetric analysis . J Therm Anal Calorim . 2009 . http://dx.doi.org/10.1007/s10973-008-9708-5 . 31
