scholarly journals ANÁLISE COMPARATIVA ENTRE COMPÓSITOS MINERAIS PRODUZIDOS COM PARTÍCULAS DE MADEIRA PASSANTE NA PENEIRA 1,2 mm

2020 ◽  
Vol 15 (2) ◽  
pp. 233-244
Author(s):  
Thaísa Mariana Santiago Rocha ◽  
Leonardo Fagundes Rosemback Miranda
Keyword(s):  
Compressive Strength ◽  
Specific Gravity ◽  
Portland Cement ◽  
Physical And Mechanical Properties ◽  
Construction And Demolition Waste ◽  
Wood Composites ◽  
Demolition Waste ◽  
Wood Residues ◽  
Wood Particles ◽  
Strength And Durability

RESUMO: Os compósitos de madeira surgiram como alternativa para o aproveitamento dos resíduos de construção e demolição (RCD) de madeira. O cimento Portland tem sido utilizado como aglomerante conferindo resistência e durabilidade, entretanto a combinação destes materiais pode resultar na inibição da pega. Em contrapartida, poucos estudos têm sido realizados com compósitos de madeira utilizando o gesso como aglomerante. O objetivo deste trabalho consiste em avaliar a influência de dois diferentes aglomerantes (cimento Portland e gesso) nas propriedades físicas e mecânicas de compósitos produzidos com partículas de madeira (de compensado, eucalipto e pínus), provenientes de resíduos de construção e demolição (RCD), passante na peneira 1,2 mm. Os resíduos de madeira de construção foram moídos, tratados, peneirados e caracterizados através da massa unitária e do teor de umidade. Foi utilizado o cimento CPV-ARI, o gesso de pega lenta, o aditivo acelerador de pega. Foram realizados os ensaios de densidade endurecida, resistência à tração na flexão e resistência à compressão, aos 28 dias. Os resultados indicaram que quanto maior a quantidade de partículas de madeira na composição, menor é a densidade e a resistência à compressão do compósito. Todos os compósitos produzidos com cimento-madeira apresentaram densidade inferior ao estipulado pela NBR 15498. As densidades dos compósitos de gesso-madeira, no teor de 15% de partículas, aproximaram-se dos valores indicados pela NBR 14715. ABSTRACT: Wood composites appear as an alternative for the reuse of construction and demolition waste (CDW) of wood. Portland cement has been used as a binder conferring strength and durability, however the combination of these materials may result in handle inhibition. In contrast, few studies have been carried out with wood composites using gypsum as a binder. In this paper the influence of two binders (Portland cement and gypsum) was evaluated in relation to the physical and mechanical properties of composites produced from wood particles (plywood, eucalyptus and pine) from construction and demolition waste (CDW) passing on the size  1.2 mm. The wood residues were ground, treated, sieved and characterized by unit mass and moisture content. The CPV-ARI cement was used, the slow gypsum plaster, the handle accelerator additive. The tests of hardened specific gravity, flexural and the compressive strength in the hardened stage at 28 days. The results indicated that the higher the amount of wood particles in the composition, the lower hardened specific gravity and the compressive strength of the composite. All composites produced with cement-wood presented a hardened specific gravity lower than that stipulated by NBR 15498. The hardened specific gravity of the gypsum-wood composites, in the content of 15% of particles, approached the values indicated by NBR 14715.

scholarly journals Construction and Demolition Waste (CDW) Recycling—As Both Binder and Aggregates—In Alkali-Activated Materials: A Novel Re-Use Concept

2020 ◽  
Vol 12 (14) ◽  
pp. 5775 ◽  
Author(s):  
Rafael A. Robayo-Salazar ◽  
William Valencia-Saavedra ◽  
Ruby Mejía de Gutiérrez
Keyword(s):  
Compressive Strength ◽  
Portland Cement ◽  
Circular Economy ◽  
Room Temperature ◽  
Heat Of Hydration ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
High Class ◽  
Construction And Demolition Wastes ◽  
Alkali Activated

This article demonstrates the possibility of producing alkali-activated materials (AAM) from a mixture of mechanically processed concrete, ceramic, masonry, and mortar wastes, as a sustainable alternative for recycling construction and demolition wastes (CDWs) under real conditions. The addition of 10% Portland cement allowed the materials to cure at room temperature (25 °C). CDW binder achieved a compressive strength of up to 43.9 MPa and it was classified as a general use and low heat of hydration cement according to ASTM C1157. The concrete produced with this cement and the crushed aggregates also from CDW reported a compressive strength of 33.9 MPa at 28 days of curing and it was possible to produce a high-class structural block with 26.1 MPa according to ASTM C90. These results are considered one option in making full use of CDWs as binder and aggregates, using alkaline activation technology thereby meeting the zero-waste objective within the concept of the circular economy.

Influence of Portland Cement Addition in the Physical and Mechanical Properties of Epoxy Resin

2015 ◽  
Vol 1088 ◽  
pp. 411-414 ◽  
Author(s):  
Francisco Augusto Zago Marques ◽  
Carlos Eduardo G. da Silva ◽  
André Luis Christoforo ◽  
Francisco Antonio Rocco Lahr ◽  
Túlio Hallak Panzera ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Composite Material ◽  
Portland Cement ◽  
Physical Properties ◽  
Epoxy Resin ◽  
Modulus Of Elasticity ◽  
Epoxy Matrix ◽  
Physical And Mechanical Properties ◽  
Response Variable

This research evaluated, with the of the analyses of variance (ANOVA), a composite material based on epoxy matrix phase reinforced with Portland cement (CP-II) particles (0%wt [100%wt of resin], 20%wt, 40%wt, 60%wt). The response-variable investigated were modulus of elasticity (E) and compressive strength (S), bulk density (ρB), apparent density (ρA) and porosity (P). The highest values of the modulus of elasticity were provided from the composites manufactured with 40wt% of cement addition. The inclusion of 60% of cement implies in a reduction in the mechanical properties when compared with the results of the composite manufactured with 40% of cement. For the physical properties, the gradually inclusion of cement provides increasing in the density of the composites, and reduce the porosity of the materials manufactured.

Influence of Portland Cement on Physical, Mechanical and Thermal Properties of Cellular Lightweight Concrete

2017 ◽  
Vol 751 ◽  
pp. 532-537
Author(s):  
Atthakorn Thongtha ◽  
Surirat Ketchaona ◽  
Jutarud Wattana ◽  
Tanapon Patanin
Keyword(s):  
Compressive Strength ◽  
Thermal Properties ◽  
Portland Cement ◽  
Room Temperature ◽  
Lightweight Concrete ◽  
Physical And Mechanical Properties ◽  
Second Step ◽  
Mechanical And Thermal Properties ◽  
Building Wall ◽  
Wall Materials

The research in this paper aims to study the physical, mechanical and thermal properties of building wall materials (Cellular lightweight concrete) with various proportions of Portland cement. The research in this paper is separated into two parts, in the first part, the density, water absorption and compressive strength of 7.0 cm x 7.0 cm x 7.0 cm concrete sample was investigated. This study found that the optimal proportion of Portland cement was 15% by weight (this condition showed the highest compressive strength of 3.62 MPa). The physical and mechanical properties of lightweight concrete conformed to the Thai Industrial Standard 2601-2013. In the second step, the thermal properties of the improved lightweight concrete, brick and commercial concrete were compared. It was found that the samples with increasing 15% by weight of Portland cement showed the lowest heat flux that affected to a lower tested room temperature as well.

scholarly journals Comparison of strength and durability characteristics of a geopolymer produced from fly ash, ground glass fiber and glass powder

2017 ◽  
Vol 67 (328) ◽  
pp. 136 ◽  
Author(s):  
H. Rashidian-Dezfouli ◽  
P. R. Rangaraju
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Portland Cement ◽  
Glass Fiber ◽  
Glass Powder ◽  
Silica Content ◽  
Ground Glass ◽  
Alkali Silica Reaction ◽  
Strength And Durability ◽  
Cement Mixtures

Strength and durability characteristics of geopolymers produced using three precursors, consisting of fly ash, Ground Glass Fiber (GGF), and glass-powder were studied. Combinations of sodium hydroxide and sodium silicate were used as the activator solutions, and the effect of different sodium and silica content of the activators on the workability and compressive strength of geopolymers was investigated. The parameters used in this study were the mass ratio of Na2O-to-binder (for sodium content), and SiO2-to-Na2O of the activator (for silica content). Geopolymer mixtures that achieved the highest compressive strength from each precursor were assessed for their resistance to alkali-silica reaction and compared against the performance of portland cement mixtures. Test results revealed that GGF and fly ash-based geopolymers performed better than glass-powder-based geopolymer mixtures. The resistance of GGF-based and fly ash-based geopolymers to alkali-silica reaction was superior to that of portland cement mixtures, while glass-powder-based geopolymer showed inferior performance.

scholarly journals Compressive Strength of Concrete with Construction and Demolition Waste and m-SAND using Additives

2019 ◽  
Vol 8 (2S10) ◽  
pp. 935-937
Keyword(s):  
Compressive Strength ◽  
Green Building ◽  
Cost Effective ◽  
Construction And Demolition Waste ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Rapid Urbanization ◽  
Manufactured Sand ◽  
Coarse Aggregates

Construction and Demolition wastes(C&D wastes) are generated in all cities of the world due to rapid urbanization. Disposing C & D waste these days is a costly affair, and raises environmental issues. Hence an attempt is made to reuse the demolished concrete as a partial replacement of natural coarse aggregates. Also due to ban of sand mining by local authorities, the cost of natural fine aggregate is very high and itself becoming a scarce material. Hence crushed stone aggregates called manufactured sand (m sand) is used, totally replacing natural fine aggregates. This concept is found to be cost effective, minimizes disposal of C & D wastes, and leads towards Green Building Concepts. Compression test on M40 concrete cubes of size 150mmx150mmx150mm are conducted at end of 7 days and 28days. Mix design for M40 concrete is made in accordance to IS: 10262-2019 with water cement ratio of 0.45 using 53 Grade Ordinary Portland cement. Superplasticizer (LIQUIFIX) is used to enhance workability. Nano Silica (NS)(1.5% by weight of cement),Wollastonite powder(WP)(10%by weight of cement) and Basalt fibres(BF)(1% by weight of cement) are added as additives. It is observed, that compressive strength of 7 days and 28 days cured samples is 25% more with the addition of all three additives compared to samples without additives. Hence the loss of compressive strength obtained by using demolished concrete as aggregates and m sand in concrete is regained with the addition of additives.

scholarly journals Research On Recycling Of Hardened Mortar From Construction And Demolition Waste

2015 ◽  
Vol 5 (2) ◽  
pp. 81-86
Author(s):  
Irina Smical ◽  
F. Filip-Văcărescu ◽  
G. Danku ◽  
V. Paşca
Keyword(s):  
Sustainable Development ◽  
Compressive Strength ◽  
Circular Economy ◽  
Standard Sample ◽  
Testing Machine ◽  
Construction And Demolition Waste ◽  
Demolition Waste ◽  
The Sustainable Development ◽  
Concrete Production ◽  
Compression Resistance

Abstract The recycling issues related to the construction and demolition (C&D) wastes in the sustainable development and the circular economy context represent a continuous challenge for researchers. This paper reveals the possibility to recycle the hardened mortar recovered from C&D wastes. Thus, the recovered hardened mortar with grains size less than 16 mm was used in the concrete structure. The compression resistance of the final concrete was determined using a Heckert 3000 KN testing machine and the results showed a better compressive strength for the samples with C&D waste content than the standard sample of about 1.19 times. This is a good premise for improving the researches related to C&D waste usage in concrete production.

scholarly journals Preliminary Analysis of the Use of Construction Waste to Replace Conventional Aggregates in Concrete

Buildings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 81
Author(s):  
Fernando A. N. Silva ◽  
João M. P. Q. Delgado ◽  
António C. Azevedo ◽  
António G. B. Lima ◽  
Castorina S. Vieira
Keyword(s):  
Compressive Strength ◽  
Coarse Aggregate ◽  
Recycled Aggregate Concrete ◽  
Construction And Demolition Waste ◽  
Recycled Aggregate ◽  
Recycled Aggregates ◽  
Fine Aggregate ◽  
Demolition Waste ◽  
Fine Aggregates ◽  
Mechanical Strengths

This work aims to study the influence of using construction and demolition waste in the replacement of coarse and fine aggregate to produce recycled aggregate concrete (RAC). A moderate compressive strength concrete made with usual fine and coarse aggregate was used as a benchmark material. Compressive and split tensile tests were performed using 120 cylindrical concrete specimens with 150 mm diameter and 300 mm length. Four-point flexural tests in reinforced beams made with conventional concrete and RAC were performed. The results obtained showed that the use of recycled fine aggregates, in both percentages of substitution investigated—50% and 100%— did not generate any deleterious influence on the values of compressive strength and split tensile strength of the RACs produced. Tin fact, the mechanical strengths of RACs produced with recycled fine aggregate were equal or higher than those from the reference concrete. The same behavior was not observed, however, when the recycled coarse aggregate was used. For this case, decreases in concrete mechanical strengths were observed, especially in compressive strength, with values around 35% lower when compared to the reference concrete. Tensile mechanical tests results confirmed the excellent behavior of all RACs made with replacement of usual fine aggregates by recycled. Bending tests performed in reinforced RAC beams had as objective to evaluate the deformation profile of the beams. The obtained results showed that RAC beams with full replacement of usual fine aggregate by the recycled aggregates have presented little changes in the global behavior, an aspect that encourages its use.

scholarly journals Peculiarities of hydration of Portland cement with synthetic nano-silica

2017 ◽  
Vol 12 (2) ◽  
pp. 101-106 ◽  
Author(s):  
Galyna Kotsay
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Portland Cement ◽  
Cement Hydration ◽  
Physical And Mechanical Properties ◽  
The Other ◽  
Nano Materials ◽  
Nano Silica ◽  
Other Hand ◽  
Materials Used

Abstract Application of nano-materials in cement products significantly, improves their properties. Of course, the effectiveness of the materials depends on their quantity and the way they are introduced into the system. So far, amongst nano-materials used in construction, the most preferred was nano-silica. This research investigated the effect of synthetic precipitated nano-silica on the cement hydration as well as, on the physical and mechanical properties of pastes and mortars. Obtained results showed that admixture of nano-silica enhanced flexural and compressive strength of cement after 2 and 28 days, however, only when admixture made up 0.5% and 1.0%. On the other hand, the use of nano-silica in the amount 2% had some limitations, due to its ability to agglomerate, which resulted in deterioration of the rheological and mechanical properties.

scholarly journals Suitability Assessment of Construction and Demolition Waste as a Highway Material

2021 ◽  
Vol 3 (1) ◽  
pp. 1-5
Author(s):  
Afroja Sultana
Keyword(s):  
Specific Gravity ◽  
Environmental Pollution ◽  
Water Absorption ◽  
Road Construction ◽  
Flexible Pavement ◽  
Construction And Demolition Waste ◽  
Test Results ◽  
Demolition Waste ◽  
Los Angeles Abrasion ◽  
Aggregate Impact Value

For Being a developing country urbanization is growing rapidly in Bangladesh and there has been a significant increase in the construction of roads. But due to lack of financial aid many of the roads are still unsealed. However, not only the utilization of Construction and Demolition Waste (CDW) in flexible pavement will be helpful for the reduction of road construction costs but also it will help to reduce environmental pollution which may be caused by disposing CDW in open area. The objective of this research is to utilize the CDW in base and sub base layers in the flexible pavement design to reduce the cost of road construction and environmental pollution. Proceeding by collecting CDW like brick from demolished building and conventional brick from kiln, a no of standard test conducted in laboratory namely Aggregate Impact Value, Crushing Value, Specific Gravity, Water Absorption and Loss Angeles Abrasion Test for three times. After analyzing the test results, we found that the average Aggregate Impact Value for CDW and Conventional Aggregate (CA) are respectively 29.52% and 23.87%, Aggregate Crushing value for CDW and CA are respectively 28.10% and 22.88%, Los Angeles Abrasion value for CDW and CA are respectively 31.47% and 28.52%, specific gravity value for CDW and CA both is 1.75, water absorption for CDW and CA are respectively 7.62% and 12.23%. After analyzing the test results and comparing with the standard value, we figure out that the CDW are useful for using base and sub base layers in the flexible pavement.

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