ESTUDO DE VIABILIDADE TÉCNICA DA APLICAÇÃO DA ESCÓRIA GRANULADA DE ALTO-FORNO EM SUBSTITUIÇÃO AO AGREGADO MIÚDO NA COMPOSIÇÃO DO CONCRETO

2021 ◽  
Vol 17 (2) ◽  
pp. 47-69
Author(s):  
Anderson Buss Woeffel ◽  
Matheus Laureth Batista

The macro sector of the civil construction industry is a major consumer of natural resources and it generates impacts, identified as social, environmental or economic, and it is necessary to develop studies that aim to rationalize this raw materials consumption and reduce the impacts generated. Since some resources used in the sector are finite, this work’s main objective is to make the concrete more ecological by replacing part of the fine aggregate of its composition for granulated slag from the blast furnace, reducing the need for sand extraction. For this study, tests were carried out with the co-product and with the fine aggregate, evaluating the properties of the concrete in the fresh and hardened states in three mixture types, the first being a reference, the second with 30% replacement and the third with 60% replacement of fine aggregate with slag. Based on the results obtained, it is noted that the granulated blast furnace slag has more similar characteristics to the sand’s; in the fresh state, the concrete showed a similar result in the three mix types; in the hardened state, it was observed that the performance of the concrete in axial compression was satisfactory; while in flexion traction the two proposed mixtures with substitution presented an unsatisfactory result.

2020 ◽  
Vol 8 (5) ◽  
pp. 4691-4696

This paper comprises of the experimental study of double skinned (DSCFT) Composite hollow columns using Geopolymer concrete. The diameter-thickness (D/t) ratio and the hollowness ratio were consideredas main parameters in designing the specimens. The Geopolymer Concrete used in this project is the most promising technique. It is composed of fly-ash, fine aggregate, coarse aggregate and alkaline solution. By using large volume of ordinary Portland cement (OPC) concrete, the production of cement increases 3% annually. The production of one ton of cement directly liberates about 1 ton of CO2 and indirectly liberates 0.4 ton of CO2 to atmosphere. Among the greenhouse gases, CO2 contributes about 67% of global warming. In this respect fly ash based geopolymer mortar is highly considerable. But most of the previous works on fly ash-based geopolymers concrete reveals that hardening is due to heat curing, which is considered as a limitation for cast in situ applications at low ambient temperatures. In order to overcome this situation, replacing the Ground blast furnace slag with fly ash for various proportions to achieve geopolymer concrete suitable for curing without elevated heat. The Scope of this project is to find optimization level of Ground Granulated blast furnace slag in geopolymer concrete for curing in ambient condition and to analyze the compressive Strength of optimized GGBS based Geopolymer Concrete filled double skinned steel tube by varying the size of the steel tubes.


2020 ◽  
Vol 44 (6) ◽  
pp. 433-439
Author(s):  
Vijayasarathy Rathanasalam ◽  
Jayabalan Perumalsami ◽  
Karthikeyan Jayakumar

This paper presents the properties of blended geopolymer concrete manufactured using fly ash and ultrafine Ground Granulated Blast Furnace Slag (UFGGBFS), along with the copper slag (CPS) as replacement of fine aggregate (crushed stone sand). Various parameters considered in this study include different sodium hydroxide concentrations (10M, 12M and 14M); 0.35 as alkaline liquid to binder ratio; 2.5 as sodium silicate to sodium hydroxide ratio and cured in ambient curing condition. Further, geopolymer concrete was manufactured using fly ash as the prime source material which is replaced with UFGGBFS (0%, 5%, 10% and 15%). Copper slag has been used as replacement of fine aggregate in this study. Properties of the fresh manufactured geopolymer concrete were studied by slump test. Compressive strength of the manufactured geopolymer concrete was tested and recorded after curing for 3, 7 and 28 days. Microstructure Characterization of Geopolymer concrete specimens was done by Scanning Electron Microscope (SEM) analysis. Experimental results revealed that the addition of UFGGBFS resulted in an increased strength performance of geopolymer concrete. Also, this study demonstrated that the strength of geopolymer concrete increased with an increase in sodium hydroxide concentration. SEM results revealed that the addition of UFGGBFS resulted in a dense structure.


2017 ◽  
Vol 12 (3) ◽  
pp. 456-469 ◽  
Author(s):  
Toshiki Ayano ◽  
◽  
Takashi Fujii ◽  
Kyoji Niitani ◽  
Katsunori Takahashi ◽  
...  

Concrete deck slabs of bridges are often deteriorated by heavy traffic and freezing and thawing actions. Spraying salt during the winter further promotes the deterioration of concrete. Some reports estimate that the length of highway roads requiring the renewal of deteriorated concrete slabs exceeds 230 km. In order to extend the lifespan of damaged bridge girders, the load for these girders must not be increased. This means that prestressed concrete (hereafter, PC) members are desirable to sustain bridge life, because they can be thinner than reinforced concrete (hereafter, RC) members. In addition, to shorten the period of traffic regulation during renewal construction, precast members should be applied. One problem in manufacturing durable precast concrete is steam curing. When the temperature, period, or both of the steam curing process are inadequate, the effect of air-entraining (hereafter, AE) agents is lost because the warmed air trapped by the AE agent expands and escapes from the concrete. Another problem is concrete fatigue. It is well known that the fatigue lives of concrete slabs in wet conditions are much shorter than those in dry conditions. Concrete slabs are waterproofed immediately after construction, but the waterproofing can be fractured soon after opening bridges, and water can reach the concrete surface. The lifespan of concrete slabs in contact with water often depends on the fatigue of the concrete. Granulated blast furnace slag sand (hereafter, BFS) can enhance the resistance to freezing and thawing actions without using AE agents. Therefore, the resistance to freezing and thawing of concrete mixed with BFS is not damaged by steam curing. The fatigue of concrete in water is also improved by the addition of BFS. Furthermore, BFS can reduce the drying shrinkage of concrete. It is advantageous to restrict the loss of prestress in PC. This study shows that precast PC members with high durability can be manufactured when granulated blast furnace slag is used as a fine aggregate in the concrete. BFS reacts with cement hydrates. It is well known that the carbonation of concrete with ground granulated blast furnace slag (hereafter, GGBF) is much greater than that with ordinary binder. However, BFS does not accelerate the carbonation of concrete. When using granulated blast furnace slag as a fine aggregate, no disadvantage in the concrete properties is detected.


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