Banca de DEFESA: SOFIA XIMENES LOPES

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : SOFIA XIMENES LOPES
DATE: 28/04/2023
TIME: 14:00
LOCAL: Pós-Graduação Engenharia Civil
TITLE:

Evaluation of Alkali-activated Mortars with Incorporation of Expanded Vermiculite

KEY WORDS:

alkali-activated slag mortars; blast-furnace slag mortar; vermiculite; autogenous shrinkage; drying shrinkage

PAGES: 94
BIG AREA: Engenharias
AREA: Engenharia Civil
SUMMARY:

The considerable increase in CO₂ emissions and the high consumption of natural resources have motivated the search for sustainable processes and materials. In particular, the construction industry has been focus of several studies because of its high energy consumption and significant CO₂ emissions. Several materials have been evaluated to totally or partially replace cement, such as blast-furnace slag, an industrial byproduct. The use of slag in cement can be a sustainable alternative to the disposal of this material, and lead to reductions in clinker demand and CO₂ emissions. The use of alternative aggregates is another approach frequently adopted to reduce the consumption of natural and energy resources. In this regard, vermiculite is an option owing to its availability and excellent acoustic and thermal insulation properties. Despite the advantages of using slag, systems containing this material exhibit high shrinkage, which may favor the ingress of aggressive agents. Therefore, this phenomenon must be studied to enable the widespread use of slag as a binder. This study aimed to evaluate the influence of vermiculite partially replacing fine aggregate in alkali-activated slag mortars, particularly focusing on shrinkage. Tests in fresh and hardened states were performed to quantify the influence of vermiculite in different mixtures. The results indicated that the use of vermiculite for the same water/binder ratio of 0.48 resulted in a reduction of the consistency index of mixtures, reduction of density in fresh state of up to 2.86%, increase of the incorporated air content (up to 91%), increase of the capillary absorption of 40.88%, and reduction of the compressive strength of up to 34.73%. Considering shrinkage results, a considerable reduction of autogenous shrinkage was observed; as for the drying shrinkage, an increase was obtained for mixtures in which dry vermiculite was used, directly proportional to the percentage adopted, whereas a decrease was observed for mixtures in which vermiculite in saturated condition was used. From the results obtained, the viability of using vermiculite as a reducing agent of the shrinkage phenomenon in alkali-activated slag mortars was confirmed.

 

COMMITTEE MEMBERS:
Presidente - 1670637 - ANTONIO ACACIO DE MELO NETO
Externo à Instituição - JOAO MANOEL DE FREITAS MOTA - IFPE
Externo à Instituição - ROMILDO MORANT DE HOLANDA - UFRPE
Externa à Instituição - YÊDA VIEIRA PÓVOAS - UPE