Application of mineral admixtures and steel fibers in experimental compositions for reactive powders concrete

Meira

Lucena

2021

RSD

Self Cite

The exponential advancement of cutting-edge technologies in the scope of civil construction, seeks to give cement-based materials the eco-efficient potential linked to mechanical performance that enables different applications. This work aims to evaluate the glass residue regarding the pozzolanic potential through ABNT NBR 5752:2014, as well as to verify whether through the characterization tests of x-ray fluorescence, x-ray diffraction and laser diffraction granulometry, if it is viable of application as supplementary cementitious material (filler), in ultra-high performance concrete. The glass residue submitted to the tests proposed in this study, was crushed in a jaw crusher, milled in a bench ball mill at 47 rpm, and was sieved in a 75 µm opening mesh (ABNT nº 200 mesh). For the test of pozzolanic activity, CP II F-40 class cement, normal sand, water from the public supply network, and superplasticizer additive were used for the mix with 25% of the residue replacing cement, while for the other characterization techniques, the glass residue was applied in its processed form (after sieving), dry or wet. The evaluated glass residue did not reach the minimum rate of 75% established by ABNT NBR 5752:2014, achieving only 45.72%, being classified as non-pozzolanic, which indicates its inert behavior in the presence of calcium hydroxide. The characterization tests confirmed, based on the specialized literature on ultra-high performance concrete, its viability as a filler when adopted as an alternative raw material for presenting chemical and mineralogical composition, in addition to granulometric distribution, very close to those used in studies that demonstrated satisfactory results when using the glass residue as an input.

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Highlights on the properties of the soda-lime-silicate glass residue that enable its use as filler in ultra-high performance concrete

Meira

Lucena

2021

RSD

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“…The Ultra-High Performance Concrete (UHPC) technology emerged in the last 25 years through a partnership between Canadian and French researchers, based on theoretical models of particle packing, exclusion of coarse aggregates, use of heat treatment at high temperatures, tension compression to the mixture in the fresh state, very low w/c factor, use of additives and mineral admixtures, and application of fibers or microfibers (Soliman & Tagnit-Hamou, 2017a;Kang, Hong & Moon, 2019;Cunha Oliveira, Meira & Lucena, 2021a). Richard & Cheyrezy (1995), reached strengths of the order of 810 MPa in analysis of compositions for Reactive Powder Concrete (RPC), one of the UHPC variants, using steel aggregate and heat treatment at 250 °C.…”

Section: Introductionmentioning

confidence: 99%

“…Bearing in mind that UHPC systems use high percentages of mineral admixtures to increase their performance in terms of axial compression and durability (Cunha Oliveira, 2020), due to the pore refinement on a microstructural scale resulting in high compactness (Cunha Oliveira, Meira & Lucena, 2021a), the glass residue incorporated into the composition as supplementary cementitious materials (SCM) (filler), due to reduced particle size, recommends its use for particle sizes below the fine aggregates, because the specific mass is similar and has less absorption (Soliman & Tagnit-Hamou, 2017a).…”

Section: Introductionmentioning

confidence: 99%

“…Verifying the presence of pozzolanic behavior in industrial by-products makes it possible to classify whether SCM are inert (filler) or reactive (pozzolan) (Cunha Oliveira, Meira & Lucena, 2021b). The pozzolanic potential of a material is configured by detonating cementing properties when it reacts in the presence of calcium hydroxide (C-H), which originates from the hydrated phases of Portland cement, producing low-density calcium silicate hydrated (C-S-H) (Cunha Oliveira, Chagas, Meira, Carneiro & Melo Neto, 2020;Cunha Oliveira, Meira & Lucena, 2021a), similar to that produced by C3S and C2S (tricalcium and dicalcium silicates), and which increases the durability of the cement matrix in the hardened state.…”

Section: Introductionmentioning

confidence: 99%

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Ultra-high performance concrete made from the insertion of glass residues as supplementary cement material

Morais

Meira

2021

RSD

Self Cite

Portland cement concrete manufacturing techniques in the world have an immense variability, since each location concentrates natural resources with unique characteristics, sometimes similar, but with always different process conditions, such as: labor, equipment, environmental conditions, processing, storage, among others. The aim of this work is to develop cementitious composites partially replacing mineral admixtures by powdered glass residues, evaluating the physical-mechanical behavior through axial compression strength, as well as the production of hydrated phases through x-ray diffraction, both at 28 days. Cement, silica fume, metakaolin, powder glass residue, polycarboxylic ether-based superplasticizer, and low temperature water were used to prepare different compositions of ultra-high performance concrete. The preparation took place with the aid of a mechanical bench mixer, and the densification was carried out with the aid of an immersion vibrator in cylindrical molds 50 x 100 mm. After unshaped, the specimens received heat treatment, with isotherm at 60°C for 36 hours, followed by wet curing in a tank saturated with calcium hydroxide, until the tests of compression strength and x-ray diffraction were carried out. The results show that the composition added with the residue, replacing metakaolin, behaved in an adequate manner, with compressive strength equivalent to the reference composition (silica fume + metakaolin), as well as the production of the same hydrated compounds. However, the application of only the glass residue or metakaolin reduced the intensity of the pozzolanic reactions, justified by the presence of a high content of calcium hydroxide in the compositions, which allows us to conclude that the powder glass residue presents viability as a filler, when replacing metakaolin in the presence of silica fume, as it does not compromise the performance of the mixtures made.

Applicability of calcined sewage sludge instead of Portland cement for coating mortars

Sá

Chagas

et al. 2022

RSD

Based on the environmental assumptions that permeate the role of researchers in enabling the use of waste in consumer goods, using sewage sludge in human consumption material has become the object of worldwide study because of the potential that it carries. Aiming to fulfill the sustainable role through the creation of mechanisms that favor the ecological coexistence between environment and human beings, the use of the calcined sewage sludge as a potentiator in the properties of the material is made possible through the construction materials, behavior. Coating mortars are currently evaluated by exposing, from the replacement of the cement by the calcined material, an effective applicability with respect to its resistance to deleterious agents. It is understood that to idealize unconventional materials with the use of residues that have high degradation power to the environment, ratifies the attempt to mitigate large and irreversible environmental impacts arising from improper and poorly planned disposal.