Use of high-resolution thermogravimetric analysis (HRTG) technique in spent FCC catalyst/Portland cement pastes

Abstract

Thermogravimetric analysis (TG) is one of the most common instrumental techniques used for the characterization of pastes, mortars and concretes based on both calcium hydroxide or Portland cement.Important information about pozzolanic materials can be assessed concerning to calcium hydroxide consumption and the formation of new hydrated products. Nevertheless, in some cases, problems associated to the overlapped decomposition processes for hydrates difficult the analysis of obtained data.In this paper the use of high resolution thermogravimetric analysis (HRTG), a powerful technique that allows separating decomposition processes in analysis of hydrated binders, was performed for spent FCC catalyst -Portland cement pastes. These pastes were monitored for 1, 4, 8 hours and 1, 2, 3, 7 and 28 curing days. In order to study the influence of the pozzolanic material (spent FCC catalyst), Portland cement replacements of 5, 15 and 30 % by mass were carried out. The presence of spent FCC catalyst in blended pastes modified the amount and the nature of the formed hydrates, mainly ettringite and stratlingite.

Earthen Plasters Stabilized through Sustainable Additives: An Experimental Campaign

“…As evidenced in the table, many overlaps are present among the thermal processes relative to the clay minerals and those of the zeolites, causing some ambiguities in the interpretation of the peaks. The results of the TG analysis after one year of curing, and the first derivative of the TG curves (DTG), are reported in Figure 11, while in Table 3, the ranges of temperature relative to the main transformations are reported [80][81][82][83][84][85][86][87][88][89][90]. As evidenced in the table, many overlaps are present among the thermal processes relative to the clay minerals and those of the zeolites, causing some ambiguities in the interpretation of the peaks.…”

Waste Slag from Heating Plants as a Partial Replacement for Cement in Mortar and Concrete Production. Part I—Physical–Chemical and Physical–Mechanical Characterization of Slag

“…This process was followed with weight loss of about 0.65% in the temperature range 25-400 • C. In the second temperature interval (400-1000 • C), an endothermic peak with high intensity was observed at 730 • C, which was accompanied with weight loss of 6.87% on the TGA curve. This peak and weight loss can be explained by decomposition of the CEM I 42.5R aluminate phase, i.e., portlandite decomposition [34][35][36], dehydroxylation of the calcium aluminate and the alumina hydrates and the decomposition of the calcite (carbonates) [34][35][36][37]. However, due to the low amount of carbonate mineral calcite in the Portland cement, this process was not visible on the DTA curve.…”

A new treatment for coconut fibers to improve the properties of cement-based composites – Combined effect of natural latex/pozzolanic materials

“…Regarding the hydration products present on the surface of the coconut fibers, Soriano et al [32] state that the compounds CSH, CAH and hydrated calcium silicoaluminates (CASH) decompose until 220°C. Moreover, the authors reported that the CH is decomposed in the range of 500-550°C.…”