Velazquez, Sergio
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Preferred name
Velazquez, Sergio
Official Name
Velázquez Rodríguez, Sergio
Alternative Name
svelazqu
Main Affiliation
ORCID
Scopus Author ID
56177465000
Researcher ID
R-6947-2018

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Spent fluid catalytic cracking catalyst for improving early strength of portland cement

2014-01-01 , Velazquez, Sergio , Borrachero, María V. , Monzó, José M. , Payá, Jordi , Vunda, Christian , Soriano, Lourdes

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Pozzolanic reaction rate of fluid catalytic cracking catalyst residue (FC3R) in cement pastes

2013 , Payá, Jordi , Monzó, José M. , Borrachero, María V. , Velazquez, Sergio

Fluid catalytic cracking catalyst residue (FC3R) is a waste material generated in the petroleum industry. Previous research has shown that FC3R exhibits excellent pozzolanic properties in Portland cement mixtures. The pozzolanic activity of FC3R was studied by means of thermogravimetric analysis (measurement of lime fixation) and cold hydrochloric acid treatment (quantification of FC3R reacted). A water/binder ratio of 0·40 was used in the study in the preparation of a control paste (without spent catalyst) and a 15% substituted FC3R paste. The selected curing temperatures were 20 and 40°C and several curing times were tested. The amount (grammes) of fixed lime by gramme of reacted catalyst indicated that approximately one part lime is chemically combined with 2·3 parts of spent catalyst. The combination of both study techniques allows determination of the optimal dosage in order to maximise use of this excellent pozzolan.

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The chemical activation of pozzolanic reaction of fluid catalytic cracking catalyst residue (FC3R) in lime pastes

2007 , Payá, Jordi , Monzó, José M. , Borrachero, María V. , Velazquez, Sergio

Previous work has shown the effectiveness of certain chemical activators, especially sodium sulphate, in improving the pozzolanic activity of fluid catalytic cracking catalyst residue (FC3R)/lime pastes, monitored by means of calcium hydroxide (CH) consumption. The influence of several chemical activators on the development of mechanical strength is described, namely sodium sulphate, calcium chloride, sodium hydroxide and NaOH– gypsum mixture. Since the study was performed in pastes, prismatic test specimens of 1 cm × 1 cm × 6 cm were used, which were proposed by Köch–Steinegger for durability studies of cement pastes. In order to evaluate the results, these were compared with the mechanical strength of mortars, and excellent correlations were obtained. The sodium sulphate activator gave very high compressive strengths, especially at early curing ages, although at longer curing ages, the paste without activator yielded satisfactory strength.

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