A Study on Environmental Load Assessment of Early Strength Activator Blast Furnace Slag

2014 ◽  
Vol 905 ◽  
pp. 383-387
Author(s):  
Young Jin Bok ◽  
Sung Ho Tae ◽  
Taeh Young Kim ◽  
Jeong Hun Park

Development of environment-friendly building materials has recently been increasing with the use of industrial waste and by-products, but concrete containing blast furnace slag (BFS) is excellent in terms of environmental load and shows relatively insufficient early strength. Development of by-products to supplement this insufficiency is deemed necessary. Therefore in this study, an early strength activator blast furnace slag (A-BFS) was developed and environment performance of the developed A-BFS was assessed to assess environmental load (CO2). As a result, early strength was developed in mortar specimen mixed with A-BFS. When environmental load (CO2) was assessed on the mortar specimen, life cycle CO2 emission from production of 1kg of A-BFS was found to be 0.057kg-CO2/kg.

2019 ◽  
Vol 278 ◽  
pp. 01005
Author(s):  
Erica Enzaki ◽  
Takashi Sakuma ◽  
Eizou Takeshita ◽  
Shigeyuki Date

In recent years, the use of blast furnace slag material is being focused as environmental loading reduction and sustainable construction. However, in general, autogeneours shrinkage of the concrete using much amount of GGBFS is large in compared to normal concrete, therefore risk of cracking should be cared. On the other hand, strength development speed of concrete at early stage will be decreasing as the dosage of GGBFS increases, even under steam curing condition. It can be considered these points will be significant disadvantage in both productivity and quality of precast concrete. So in this study, early strength type expansive agent and setting accelerator were used in combination. As a result, it was confirmed that compressive strength at early stage is obviously increased. And steam curing temperature can be reduced about 10 degrees, and also, 600×10-6 of restraint expansion was obtained.


2014 ◽  
Vol 905 ◽  
pp. 388-391
Author(s):  
Taeh Young Kim ◽  
Sung Ho Tae ◽  
Jin Hyoung Kim ◽  
Keun Hyeok Yang

In relation to global warming, there is a need for development of alternative material to reduce cement use by concrete. Accordingly in this study, A-BFS (Activator Blast Furnace Slag) mixed with an activator composed of industrial wastes such as wastewater sludge and sewage sludge was developed. Physical property for compressive strength development was tested on concrete mixed with the developed A-BFS. In addition, environmental load (CO2) emission and reduction performance were analyzed on concrete mixed with A-BFS.


2021 ◽  
Vol 8 ◽  
Author(s):  
Xiyao Zheng ◽  
Jun Wu

One-part or “just add water” geopolymer is a cementitious material, which is friendly to environment and users in applications. However, the mechanical behavior of the soft soil stabilized by one-part geopolymer is not well acknowledged. In this study, soft clay was stabilized with ground granulated blast furnace slag (GGBFS) and fly ash (FA)-based geopolymer, which is a mixture of solid aluminosilicate precursor (Al-Si raw materials: GGBFS and FA), solid alkali activator, and water. The objective was to adopt one-part geopolymer as an alternative soil binder to completely replace ordinary Portland cement (OPC) for stabilizing the soft clay and evaluate the effect of the factors (i.e., GBFS/FA ratio in Al-Si precursor, activator/Al-Si precursor ratio, and water/binder ratio) that influenced the early strength. Results showed that the increase of the FA content in the Al-Si precursor increased the unconfined compressive strength (UCS) values significantly through the geopolymerization process. The highest UCS values were achieved with 90% GGBFS to 10% FA in the precursor when the activator/precursor and water/binder ratio is 0.15 and 0.7, respectively. The UCS values of geopolymer-stabilized clay could reach 1.5 MPa at 14 days at ambient temperature, which is much higher than that of OPC-stabilized clay. The microstructure and mineralogy analyses indicated that the prolific hydration products, such as calcium silicate hydrate (C-S-H), calcium aluminum hydrate (C-A-H), and calcium aluminum silicate hydrate (C-A-S-H), contributed greatly to strengthen the soft clay by forming the soil skeleton and infilling among clay particles, while sodium aluminosilicate (N-A-S-H) gel is only served to fill the part of porosities in the soil and cannot effectively enhance the UCS of the one-part geopolymer-stabilized soft clay. This paper results suggested that one-part GGBFS-FA–based geopolymers have the potential to replace OPC in the manufacture of stabilized soft clay.


Author(s):  
Jean Noël Yankwa Djobo ◽  
Dietmar Stephan

AbstractThis work aimed to evaluate the role of the addition of blast furnace slag for the formation of reaction products and the strength development of volcanic ash-based phosphate geopolymer. Volcanic ash was replaced by 4 and 6 wt% of ground granulated blast furnace slag to accelerate the reaction kinetics. Then, the influence of boric acid for controlling the setting and kinetics reactions was also evaluated. The results demonstrated that the competition between the dissolution of boric acid and volcanic ash-slag particles is the main process controlling the setting and kinetics reaction. The addition of slag has significantly accelerated the initial and final setting times, whereas the addition of boric acid was beneficial for delaying the setting times. Consequently, it also enhanced the flowability of the paste. The compressive strength increased significantly with the addition of slag, and the optimum replaced rate was 4 wt% which resulted in 28 d strength of 27 MPa. Beyond that percentage, the strength was reduced because of the flash setting of the binder which does not allow a subsequent dissolution of the particles and their precipitation. The binders formed with the addition of slag and/or boric acid are beneficial for the improvement of the water stability of the volcanic ash-based phosphate geopolymer.


2014 ◽  
Vol 1052 ◽  
pp. 392-395 ◽  
Author(s):  
Li Xia He

High Ti-bearing blast furnace (BF) slag is the smelting waste of vanadium titano-magnetite. It has great production but low utilization. The high Ti-bearing BF slag is used in building materials industry, which recycles waste material, saves resources and energy, benefiting environmental protection and achieving sustainable development of resources. Study on the recycling of high Ti-bearing BF slag will be an important subject of our researches in future.


2010 ◽  
Vol 168-170 ◽  
pp. 709-715
Author(s):  
Dongsik Oh ◽  
Doheom Song ◽  
Seongseok Go

Hwangtoh (loess) has pozzolanic properties that mean it can be used as a cement admixture when activated at high temperatures, and that it can be used in combination with building materials such as fly ash or blast furnace slag. This study aimed to analyze the relationship between the compressive strength and the brick bond strength of various mortars containing hwangtoh, and also to find the optimum mixing conditions for the use of hwangtoh. It was found that the mortars’ strength properties are significantly influenced by the water/cement ratio W/C and the activated hwangtoh substitution ratio. We recommend the following materials and mixing conditions: W/C 60%, a cement substitution ratio of activated hwangtoh of 20 ~ 25%, and the addition of 10% blast furnace slag to improve the compressive strength of such mortars.


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