Banca de DEFESA: FERNANDA MORAIS LIMA

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : FERNANDA MORAIS LIMA
DATE: 29/05/2024
TIME: 09:00
LOCAL: meet.google.com/cmd-shxq-cpt
TITLE:

Evaluation of a soil for 3D printing on earth stabilized with cement, metakaolin and filler

KEY WORDS:

Additive Manufacturing. 3D printing soil-cement. Constructability.

PAGES: 60
BIG AREA: Engenharias
AREA: Engenharia Civil
SUBÁREA: Construção Civil
SPECIALTY: Materiais e Componentes de Construção
SUMMARY:

Earth construction is one of the oldest and most widespread vernacular building techniques, as it is an ecological, sustainable, affordable material, which reduces the impact of greenhouse gases for the house-building industry. The aim of this work is to analyse a soil classified as sandy-silt and see if it is compatible with the 3D printing process, stabilizing it with Portland Cement using chemical additives to provide the pumpability required for printing, partially replacing the cement with mineral additions (metakaolin and limestone filler), so that the 3D printing mixture in cement-stabilized soil (3DTC) has a paste volume suitable for the printing system, but with low Portland Cement contents. The experimental program began with an empirical analysis of the mixtures, starting with the 1:1 cement:soil mixture, known as the reference (REF), in order to obtain a 3DTC mixture with a consistency compatible with the extrusion method of the 3D printer available at UFRN, in order to establish the chemical additive contents and the water/dry material ratio compatible with the printing speed and nozzle height conditions. From this mixture, the reduction in cement consumption of the REF mixture was analyzed, in two mixtures called T15%C and T20%C with proportions of 0.15:0.85:1 and 0.2:0.80:1 (cement:mineral additions:sand). The number of possible layers for printing 3DTC blocks to be built continuously and without crumbling was then determined using a constant printing speed of 80 mm/s with a deposition height of 1 cm. With these printing conditions established, 6 3DTC blocks were printed, of each composition, with dimensions of 14 cm x 14 cm in cross section and 16 cm in height, where 3 blocks were subjected to dimensional analysis and then the axial compressive strength was determined, and 3 blocks were used to extract small pieces (40x40x160 mm) to carry out compressive strength and flexural tensile strength tests. With the mixtures analyzed, it was possible to build 3DTC blocks with cement consumption in the T15%C -113.60 kg/m³ and T20%C - 152.78 kg/m³ mixtures and make them printable with cement reduction levels of 87% and 82%, respectively, compared to the reference mixture (REF), which used only cement and soil in a 1:1 ratio by mass. The reference 3DTC block had the highest compressive strength (19.8 MPa) of the three mixes evaluated, due to the high cement content in the mix. The T15%C and T20%C mixtures had block strengths of 3.1 MPa and 3.0 MPa, respectively, making them suitable for masonry construction.

COMMITTEE MEMBERS:
Interno - ***.621.844-** - MARCOS ALYSSANDRO SOARES DOS ANJOS - IFRN
Interna - 1507841 - MARIA DAS VITORIAS VIEIRA ALMEIDA DE SA
Externo à Instituição - NORMANDO PERAZZO BARBOSA - UFPB