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| Binder analyzed | Purpose of TGA | Sample preparation/gas used/sample weight and heating rate | Temperature intervals | Results and comments | Reference |
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PC60FA40
PC57.5FA40 + 2.5nS
PC55FA40 + 5.5nS
Mortars @w/b = 0.5 | Measure pozzolanic activity in terms of Ca(OH)2 content | Samples were oven dried @105°C for 4 h
Atmospheric pressure
About 20 mg
15°C/min | Weight loss between 440 and 510°C due to decomposition of Ca(OH)2 | OPC + type F FA + colloidal nS of 20 nm and 10 nm average particle size
Depletion of Ca(OH)2 at high FA and nS content pastes, cured in water at 70°C for 7 days, did not allow further hydration of FA. In general decrease in hydration degree of FA at later ages due to the low Ca(OH)2 content. | [16] |
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| 20 g of Ca(OH)2 content + 5 g of colloidal nS compared with 20 g of Ca(OH)2 content + 5 g of μS at both @w/b = 2 | Ca(OH)2 content at different ages | Limewater curing
Hydration arrested with acetone and oven – dried at 105°C for 4 h | @440–510°C: decomposition of Ca(OH)2 | Ca(OH)2 contents were calculated on the ignited basis at 950°C for 30 min
Pozzolanic reaction of nS was completed by day 7, however, for μS, over one month was needed. | [17] |
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| 1%, 2%, and 3% halloysite nanoclay by mass replacement of CEMI in mortar 95% CEMI-32.5 + 5% μS + 2% SP @w/b = 0.45—limewater curing | Measure Ca(OH)2 consumption | Not mentioned (n/m) | Peaks
@105–120: decomposition of C-S-H
@105–120: decomposition of gehlenite hydrate (C2SAH6)
@295–320: decomposition of hydrogarnet (C3SAH6)
@480–490°C: dehydroxylation of Ca(OH)2 | Differential scanning calorimetry (DSC) at 28 days showed consumption of Ca(OH)2 towards formation of C–S–H. | [18] |
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| OPC + 0.5%, 1%, 1.5% and 2% nS by mass replacement of OPC in mortar | Measure pozzolanic activity | Saturated LS curing for 28 d. Then in water until day 90.
N2
4°C/min, from 100 to 650°C | n/m | The loss in weight of the specimens is increased by increasing the nanocontent in concretes, maybe due to more formation of hydrated C–S–H gel. | [19] |
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| 5% nS by mass replacement of OPC mix, 7- and 28-day old | Hydration of OPC paste and 5% nS paste | n/m
From 20 to 1000°C | @120–190°C: evaporation of capillary water, decomposition of C–S–H
@450–500°C: dehydroxylation of Ca(OH)2
@700–780°C: Decarboxylation of CaCO3 | Increased hydration with use of nS. | [20] |
| 5% nS by mass replacement of OPC | Study of decomposition of hydration products | n/m
N2
10°C/min
20–1000°C-held @105°C for 2 hours to remove free water | @20–105°C: loss of free water and decomposition of ettringite
@105–400°C: gradual mass loss due to dehydration of C–S–H and loss of interlayer, absorbed and chemically bound water
@450°C: dehydroxylation of Ca(OH)2 | Reduction in amount of Ca(OH)2 in sample with nS shows evidence of pozzolanic reaction. | [21] |
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1, 2, 3, 4, and 5% nS by mass replacement of OPC + 1% SP @w/b = 0.4
nS was dispersed in the SP | Study of decomposition of hydration products | n/m
N2
4°C/min
From 110 to 650°C | 110–650°C: dehydration of hydrated products | Powder 99.9% pure nS of 15 nm average particle size
After 28 days of curing, mass loss of samples increased with increasing nS content up to 4% by mass
SP: polycarboxylate with condensate defoamer base admixture. | [22] |
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CEMI-52.5R + SP1.2
PC80μS20 + SP1.2
PC96.5nS3.5 + SP3
PC87.8μS12.2 + SP1.2
PC87.8μS10.2nS2 + SP1.2
All @w/b = 0.35
SP: carboxylic acid
nS: 30% solids by mass | To study the effect of μS and nS and their combined use | Water curing at 21°C for 7, 28, and 90 days, samples with w/b ratio of 0.35 N2
From 27 to 1000°C.
10°C/min | @∼100°C: evaporation of water
@115–125°C: partial dehydration of C–S–H
@120–130°C: partial dehydration of aft
@180–200°C: partial dehydration of AFm
@450–550°C: dehydration of Ca(OH)2
@∼800°C: decarboxylation of CaCO3 | For 7 and 28 days (up to 400°C), samples with 3.5% nS and 2 + 10.2% nS + μS showed a higher weight loss when compared to 0% nS and 0 + 12.2% nS + μS, while for 20% μS, it was lower than that of 0% μS. | [23] |
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| 2%, 4%, 6%, and 8% nanometakaolin (NMK) by mass replacement of CEM-I mortars @w/b = 0.5 | To study the effect of NMK | 20°C/min
N2 | Peaks
@105–110°C: decomposition of C–S–H
@160°C: decomposition of gehlenite
@350°C: decomposition of hydrogarnet
@470°C: dehydroxylation of Ca(OH)2
@580°C: phase change of quartz going from alpha level to beta level | DSC analyses: the addition of NMP led to the consumption of Ca(OH)2 and its transformation from well crystalline to ill-crystalline phases. | [24] |
| 0.2%, 0.4%, 0.6%, and 0.8% OMMT by mass replacement of ASTM-I PC @w/b = 0.55 | n/m | n/m
up to 1400°C | Peaks
@100°C: capillary water evaporates
@470°C: dehydroxylation of Ca(OH)2
@720°C: decarboxylation of CaCO3
@1300°C: glass transition temperature transforming the cement from powder into a melted material. | | [25] |
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0%, 0.5%, and 2% of OMMT nC by mass replacement of type I PC
mortars @w/b = 0.4, 0.485, and 0.55 | Verification of organomodification of OMMT | n/m | @150°C: partial dehydration of C–S–H
@300–400°C: The organomodifier decomposed | Verification of organomodification of clay particles. | [26] |
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| CEM I 52.5R with polycarboxylic ether-based superplasticizer + limestone and quartz powder + sandstone and sand + 13 mm steel fibres 1, 2, 3, 4, and 5% nS | Effect of nS on ultra-high-performance concrete | Curing for 28 days hardened samples ground to powder and tested at 10°C/min | Peaks
@105°C: capillary water evaporates
@450°C: dehydroxylation of Ca(OH)2
@800°C: decarboxylation of CaCO3 | The addition of superplasticizer retarded the dormant period of cement hydration. This effect is compensated by the addition of nS as age progresses. | [27] |
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| Cement was replaced by FA and nS. The dosages of nS varied from 0% to 1%, 3%, and 5% by mass of the cementitious materials. The w/b and sand-binder ratios were 0.2 and 1.2, respectively | Effect of nS on ultra-high-performance cementitious composites | Samples were soaked in alcohol for 48 h to arrest hydration and then milled to 80 lm sieve particles, and then were subsequently dried, sealed, and tested at 7 days under TGA | Peak
@110°C: capillary water evaporates
@135–150°C: decomposition of C–S–H
@400–500°C: dehydroxylation of Ca(OH)2
@710°C: decarboxylation of CaCO3
@800–910°C: curve bending towards exothermic reactions can be related to the transformation of some C2S from a0H crystallographic form to a0L crystallographic form
@1210°C: endothermic peak may be induced by the transformation of some C2S from a0H crystallographic form to a crystallographic form. | Pozzolanic and filler effects of nS were confirmed. Above 3% of nS addition serious agglomeration occurred. | [28] |
| CEM I 42.5R concrete + commercial nS suspension (10% solids by weight of water with nominal mean particle size of 20 nm) @0, 0.5, 1, and 1.5% replacement | Effect of nS and different w/b ratios on binary concretes | Approximately 100 mg of ground fragments of concrete with w/b = 0.65 at 1.5% nS substitution was analyzed under N2 flow of 50 mL/min.
Temperature 25°C up to 900°C @ a rate of 10°C/min temperature was held at 105°C for 2 hours to promote evaporation of free water. | @420–510°C: dehydroxylation of Ca(OH)2
@720–810°C: decarboxylation of CaCO3 and dolomite weight loss | The amount of CH consumed was estimated. Strength gain at higher nS additions is directly related to the w/b ratio. | [29] |
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| Tricalcium silicate (C3S) was prepared in the laboratory using an electric furnace at an elevated temperature of 1500°C powder nS was added at 1, 3, 5, and 10% with w/b = 0.4 | Determination of CH and C-S-H content in hydrated C3S paste | Heating rate of 5°C/min under nitrogen flow | 400–500°C is due to the dehydration of CH; 600–800°C is because of the decarbonation of CaCO3
The remaining mass loss between 105 and 1000°C is considered as the dehydration of C–S–H | Maximum nucleation effect of nS at 8 h, when the rate of product C–S–H formation was higher than the control (∼66% additional C–S–H and ∼61% more CH with 10% nS addition)
At 24 h of hydration, ∼25% additional C–S–H was formed and CH content reduced by ∼32% with 10% addition showing the pozzolanic effect of nS. | [30] |
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| PC 40%, LS 20%, and FA 20% by mass of binder and nS as PC replacement | Determination of CH and C-S-H content in hydrated paste | Heating rate of 10°C/min under nitrogen flow up to 1000°C | @105–180°C: decomposition of C–S–H, ettringite, and gehlenite
@185–200°C and 270–380°C: monosulfate of
@440–510°C: dehydroxylation of Ca(OH)2
@700–810°C: decomposition of CaCO3 | Increase in the Ca(OH)2 towards the production of additional CaCO3 directly correlated with compressive strength increase. | [10] |
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| PC 60% and LS 40% by mass of binder and nS as PC replacement | Determination of CH and C–S–H content in hydrated paste | Heating rate of 10°C/min under nitrogen flow up to 1000°C | @105–180°C: decomposition of C–S–H, ettringite, and gehlenite
@440–510°C: dehydroxylation of Ca(OH)2
@700–810°C: decomposition of CaCO3 | Consumption of Ca(OH)2 towards the production of additional C–S–H directly correlated with compressive strength increase. | [7–9, 31] |
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| PC 60%, LS 40% by mass of binder and 1% nano-montmorillonite as PC replacement | Determination of C–S–H content in hydrated paste | Heating rate of 10°C/min under nitrogen flow up to 1000°C | @105–180°C: decomposition of C–S–H, ettringite and gehlenite | Production of additional C–S–H | [32] |
| 50% lime putty 50% nano-montmorillonite dispersion and 20% lime putty 80% nano-montmorillonite dispersion | Assessment of pozzolanic activity | Heating rate of 10°C/min under nitrogen flow up to 1000°C | @105–300°C: dehydration of lime putty and surfactant
@400–550°C: dehydroxylation of Ca(OH)2 and nano-montmorillonite
@600–810°C: decomposition of CaCO3 and nano- montmorillonite | Consumption of Ca(OH)2 towards the production of additional C–S–H directly correlated with compressive strength increase | [33] |
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| PC replacement at 1 wt% of organically modified montmorillonite @ different cation exchange degrees 0.6, 0.8, and 1.0 and at water-to-solid ratio of 0.27 | Pozzolanic activity vs cation exchange degree | TGA @7, 28 and 56 days
After predrying, the samples were heated up to 900°C at 10°C/min rate in a flowing nitrogen atmosphere | Mass loss up to 110°C: loss of adsorbed water and part of C–S–H
@110–220°C: loss of interlayer water of C–S–H and dehydration of C-A-H, C-A-S-H and C-A-C-H,
@400–475°C: dehydroxylation of Ca(OH)2
@550–760°C: decomposition of complex mixture of carbonated phases, calcite and structural OH groups from hydrated calcium silicates | The content of hydration products was specified by simultaneous thermal analysis (STA)—differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA). OMT with cation-exchange degree of 0.8 seems to be more suitable for cement substitution than OMT of higher cation exchange degree. | [34] |
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| Synthetic C–S–H by hydration of C3S in excess of water compared to C-S-H+ nS particles or C–S–H+ amine functionalized nS particles | Determination of amount of water and carbonation | Heating rate of 5°C/min under nitrogen flow up to 800°C | For the nS addition:
20–200°C corresponds to adsorbed and C–S–H water loss
200–800°C: silanol groups condense to siloxanes
For the functionalized nS addition:
20–200°C corresponds to adsorbed and C–S–H water loss
200–400°C: silanol groups condense to siloxanes
450–800°C: decomposition of amino group (only for the functionalized nS mix) | The addition of nS particles inhibited the formation of carbonated phases, reducing C-S-H carbonations and increased the length of the silicate chains, reducing the size or the gel pores in C–S–H. | [35] |
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