Studies of conversion progress of calcium aluminate cement hydrates by thermal analysis method

Pacewska, Barbara; Nowacka, Mariola

doi:10.1007/s10973-014-3804-5

Cited by 61 publications

(17 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Three trails have been carried out, and the values given in the Table 4 are mean values of these trails. The mass loss between RT-400°C is pertaining to the dehydration of various types of water in gel pore, chemically bound water, capillary water, and hydration products of cement composites such as calcium silicate hydrates (C-S-H), calcium aluminosilicate hydrates (C-A-S-H) [49], and ettringite. In the case of LS20, the mass loss (14.84 %) is less than the CON (15.63 %), which shows that the above phases are lesser than the CON pastes.…”

Section: Resultsmentioning

confidence: 99%

Effect of high temperature on the properties of ternary blended cement pastes and mortars

Maheswaran

Iyer

Palani

et al. 2015

J Therm Anal Calorim

View full text Add to dashboard Cite

This paper presents experimental study to investigate the effect of high temperature up to 800°C on the properties of ternary blended Portland cement, lime sludge (LS), a residual solid from paper and pulp industry, with silica fume (SF) and nanosilica (NS). Physicochemical properties and mechanical behavior of ternary blended cement are studied. The replacement of cement by LS is fixed throughout as 20 % except control paste/mortar. In addition to the replacement of LS, SF by 3 and 6 % and NS by 1.5 and 3 % are incorporated in cement paste and mortar. The phase changes due to the thermal effect of all the 28-day water-cured composite pastes are monitored by XRD and thermal analysis by TG-DTG. Unstressed residual compressive strength tests are used in this study for the mortars. Results show that the incorporation of LS-SF cement composites with cement replacement level up to 26 % increases the compressive strength significantly at ambient temperature as well as after 2-h exposure to 500°C compared to control mortars, but spalling of mortars occurs at 800°C after 28 days of water curing. In the case of LS-NS cement composites, the residual compressive strength reduces considerably at all the temperatures, but there is no occurrence of spalling.

show abstract

Section: Resultsmentioning

confidence: 99%

Effect of high temperature on the properties of ternary blended cement pastes and mortars

Maheswaran

Iyer

Palani

et al. 2015

J Therm Anal Calorim

View full text Add to dashboard Cite

show abstract

“…The prepared pastes were poured into flat‐bottomed steel plates which were covered with a layer of plastic film. As the hydration of CAC is highly exothermic and rapid in heat production, the pastes in the steel plate were evenly distributed with a thickness of less than 2 mm in order to avoid significant temperature rise during hydration because of CAC hydration self‐heating. Then, the pastes were placed at 10 and 20°C for 24 hours, respectively and parts of the as‐cured cement pastes were frozen to halt the hydration at −50°C for 1.5 hour, and then dried in a vacuum box under a pressure of 60 Pa at 20°C for 24 hours as references (hydrates CAH 10 and C 2 AH 8 ).…”

Section: Methodsmentioning

confidence: 99%

Conversion of calcium aluminate cement hydrates at 60°C with and without water

Zhang

et al. 2018

J Am Ceram Soc

View full text Add to dashboard Cite

There have been different hypotheses about the transformation mechanisms of calcium aluminate cement hydrates and this work aims to clarify the long‐running debate about the conversion approaches. In this work, CAH10 and C2AH8 were produced from the pastes of calcium aluminate cement (CAC) cured for 24 hours at 10 and 20°C separately. And the cured pastes were continually cured at 60°C for 3 days with water and without water, respectively. The hydration of the pastes was halted by freeze‐drying, and the phases and microstructure of hydrates were investigated by XRD and SEM, respectively. The results indicate that CAH10 and C2AH8 converted into C3AH6 and AH3 in water presence at 60°C, but did not transform into C3AH6 and AH3 without water. It is confirmed that the conversion of CAH10 and C2AH8 to C3AH6 and AH3 happens through preceding solution of CAH10 and C2AH8 and subsequent precipitation of C3AH6 and AH3.

show abstract

“…Analysis of thermal dehydration of hardened binder pastes by DTA and TG DTA-TG is considered one of the most powerful tools in the investigation of the hydration of CAC pastes [16,26]. Curves have yielded useful results on the calcium zirconium aluminate hydrated for various lengths of time under different conditions [14][15][16] (Fig.…”

Section: Spectroscopic Analysis (Ft-ir) Of Hardened Binder Pastesmentioning

confidence: 99%

Study of the hydration of calcium zirconium aluminate (Ca7ZrAl6O18) blended with reactive alumina by calorimetry, thermogravimetry and other methods

Madej

Szczerba

2015

J Therm Anal Calorim

View full text Add to dashboard Cite

The reactivities of hydratable alumina, calcium zirconium aluminate and their binary mixtures were investigated by calorimetric method, X-ray diffraction, Fourier transform infrared spectroscopy (FT-IR), differential thermal/thermogravimetric analysis (DTA-TG) and scanning electron microscope observations. The rate of heat evolution illustrates only one distinct exothermic peak in the mixtures containing calcium zirconium aluminate which corresponds the subsequent precipitation of hydrated material mainly in the form of amorphous CaO-Al 2 O 3 -H 2 O phases and crystalline C 4 AH 19 occurs simultaneously after wetting of Ca 7 ZrAl 6 O 18 grains. Nevertheless, coexistence of both unstable calcium aluminate hydrates (CAH 10 , C 2 AH 8 , C 4 AH 19 ) and thermodynamically more stable C 3 AH 6 detected by FT-IR and DTA-TG in the paste cured at 20°C may have originated in the thermally induced partial conversion reaction due to the considerable amount of heat generated by the Ca 7 ZrAl 6 O 18 hydration. It is also found that curing temperature affected the hydration products formed in the hydration products of both Ca 7-ZrAl 6 O 18 and Ca 7 ZrAl 6 O 18 /Al 2 O 3 blends. Reactive alumina influences the hydration behavior of Ca 7 ZrAl 6 O 18 facilitating the nucleation and growth of hydration products, causes characteristic changes in the microstructure of hardened blended pastes and favors recrystallization of dehydrated calcium aluminates.

show abstract

Studies of conversion progress of calcium aluminate cement hydrates by thermal analysis method

Cited by 61 publications

References 13 publications

Effect of high temperature on the properties of ternary blended cement pastes and mortars

Effect of high temperature on the properties of ternary blended cement pastes and mortars

Conversion of calcium aluminate cement hydrates at 60°C with and without water

Study of the hydration of calcium zirconium aluminate (Ca7ZrAl6O18) blended with reactive alumina by calorimetry, thermogravimetry and other methods

Contact Info

Product

Resources

About