scholarly journals Determining k-Value with Regard to Freeze-Thaw Resistance of Concretes Containing GGBS

Materials ◽  
2018 ◽  
Vol 11 (12) ◽  
pp. 2349
Author(s):  
Jerzy Wawrzeńczyk ◽  
Agnieszka Molendowska ◽  
Tomasz Juszczak
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Trial And Error ◽  
K Value ◽  
Freeze Thaw ◽  
Resistance Analysis ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mix ◽  
Furnace Slag ◽  
Slag Content

The European concrete standard EN 206 introduces the k-value concept as one of the three methods allowing the use of granulated blast furnace slag in the design of the freeze-thaw-resistant concrete mix. It is assumed that the freeze-thaw durability of the concrete, whose composition (w/c ratio) has been corrected by adopting a certain k-value, is the same as the freeze-thaw resistance of the reference concrete made with the cement containing no addition (CEM I). This article presents the results of freeze-thaw resistance analysis (modified with the ASTM C666A standard Class XF3) of 24 series of concretes made with a binder containing varied amounts of slag, with a w/b ratio ranging from 0.25 to 0.55. The aim of the study was to estimate the k-value as a parameter defined by the w/b ratio and the slag content in the binder. In this approach, the k-value is determined by trial and error in such a way that the deformation of the concrete specimens containing the slag corresponds to the deformation of the reference concrete. As shown by the analysis, the k-value decreases with increasing slag content in the binder.

scholarly journals Mechanical Properties of Self-Compacting Geopolymer Concrete Using Fly Ash and GGBS

2018 ◽  
Vol 7 (1) ◽  
pp. 19-23
Author(s):  
S. Thirupathiraj .
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Geopolymer Concrete ◽  
Cement Concrete ◽  
Self Compacting Concrete ◽  
Split Tensile Strength ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mix ◽  
Furnace Slag

Cement is the core content for the concrete mix. Manufacturing of cement causes CO2 emission which leads to the pollution, health and environmental problems like global warming to control over the adverse effect we can prefer geopolymer concrete which is not a cement concrete. Factory wastes such as fly ash, ground granulated blast furnace slag (GGBS), silica fume and Metakaolin can be used as alternate for cement. This study mainly focus on the ratio of fly ash and ground granulated blast furnace slag (GGBS) for optimum levels which nearly matches the cement concrete properties. This study involves the various tests like slump flow, compression testing, split tensile strength and flexural strength of self-compacting geopolymer concrete. Self-compacting concrete is a highly flowable concrete that spreads into the form without the need of mechanical vibration. Self-compacting concrete is a non-segregating concrete that is placed by means of its own weight. The advantages include improved constructability, Labour reduction, bond to steel, Flow into complex forms, reduced equipment wear etc. The aim of this study is to achieve an optimum self-compacting concrete geopolymer concrete mix proportion using fly ash and ground granulated blast furnace slag (GGBS). Then the study will be further extended by investigating the durability properties of self-compacting geopolymer concrete.

scholarly journals Thermal Analysis of Mass Concrete Containing Ground Granulated Blast Furnace Slag

CivilEng ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 254-271
Author(s):  
Guadalupe Leon ◽  
Hung-Liang (Roger) Chen
Keyword(s):  
Blast Furnace ◽  
Thermal Properties ◽  
Temperature Difference ◽  
Blast Furnace Slag ◽  
Accurate Estimation ◽  
Early Age ◽  
Mass Concrete ◽  
Granulated Blast Furnace Slag ◽  
Concrete Mix ◽  
Furnace Slag

In this study, the early age thermal properties of a concrete mix containing ground granulated blast furnace slag (GGBFS) were investigated and incorporated in a finite-element model. A two-term exponential degree of hydration function was proposed to better capture the early age behavior. An FEM program (ABAQUS) was used to predict the temperature time-history of three 1.2-m (4-ft) cubes cast with a mix design containing 50% replacement of the cement by weight with GGBFS. The FEM predictions match well with the experimental temperature measurements. Results show that using the measurements of the thermal properties, an accurate estimation of the temperature difference can be obtained for a concrete mix containing GGBFS, and engineers can use the estimated temperature difference to take preventative measures to minimize the risk of thermal cracking.

The Influence of the Properties of the Material Used for Obtaining Geopolymers on Their Structure and Compressive Strength

2017 ◽  
Vol 68 (6) ◽  
pp. 1182-1187
Author(s):  
Ilenuta Severin ◽  
Maria Vlad
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Wheat Straw ◽  
Red Mud ◽  
Blast Furnace Slag ◽  
Complex Structure ◽  
Point Of View ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag ◽  
Straw Ash

This article presents the influence of the properties of the materials in the geopolymeric mixture, ground granulated blast furnace slag (GGBFS) + wheat straw ash (WSA) + uncalcined red mud (RMu), and ground granulated blast furnace slag + wheat straw ash + calcined red mud (RMc), over the microstructure and mechanical properties of the synthesised geopolymers. The activation solutions used were a NaOH solution with 8M concentration, and a solution realised from 50%wt NaOH and 50%wt Na2SiO3. The samples were analysed: from the microstructural point of view through SEM microscopy; the chemical composition was determined through EDX analysis; and the compressive strength tests was done for samples tested at 7 and 28 days, respectively. The SEM micrographies of the geopolymers have highlighted a complex structure and an variable compressive strength. Compressive strength varied from 24 MPa in the case of the same recipe obtained from 70% of GGBFS + 25% WSA +5% RMu, alkaline activated with NaOH 8M (7 days testing) to 85 MPa in the case of the recipe but replacing RMu with RMc with calcined red mud, alkaline activated with the 50%wt NaOH and 50%wt Na2SiO3 solution (28 days testing). This variation in the sense of the rise in compressive strength can be attributed to the difference in reactivity of the materials used in the recipes, the curing period, the geopolymers structure, and the presence of a lower or higher rate of pores, as well as the alkalinity and the nature of the activation solutions used.

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