scholarly journals Development of Low-Alkali, Fly Ash/Slag Geopolymers: Predictive Strength Modelling and Analyses of Impact of Curing Temperatures

Minerals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 60
Author(s):  
Supphatuch Ukritnukun ◽  
Pramod Koshy ◽  
Clayton Feng ◽  
Aditya Rawal ◽  
Arnaud Castel ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Cold Weather ◽  
Strength Development ◽  
Compressive Strength Development ◽  
Predictive Strength ◽  
Furnace Slag ◽  
Slag Content

The present work analyses the effects of curing temperature (25°, 40°, 60 °C for 24 h), silicate modulus Ms value (1.5, 1.7, 2.0), and slag content (10, 20, 30, 40 wt%) on the compressive strength development (1, 7, 14, 28 days) of low-alkali geopolymer mortars with matrices from fly ash and blast furnace slag. These data were used to generate predictive models for 28-day compressive strength as a function of curing temperature and slag content. While the dominant variable for the 1-day compressive strength was the curing temperature, the slag content was dominant for the 28-day compressive strength. The ratio of the 1-day and 28-day compressive strengths as a function of curing temperature, Ms value, and slag content allows prediction of the maximal possible curing temperature and shows cold-weather casting to present an obstacle to setting. These data also allow prediction of the 28-day compressive strength using only the 1-day compressive strength.

scholarly journals Evaluation of Strength Development in Concrete with Ground Granulated Blast Furnace Slag Using Apparent Activation Energy

Materials ◽  
2020 ◽  
Vol 13 (2) ◽  
pp. 442 ◽  
Author(s):  
Hyun-Min Yang ◽  
Seung-Jun Kwon ◽  
Nosang Vincent Myung ◽  
Jitendra Kumar Singh ◽  
Han-Seung Lee ◽  
...  
Keyword(s):  
Activation Energy ◽  
Compressive Strength ◽  
Blast Furnace ◽  
Apparent Activation Energy ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Strength Development ◽  
Replacement Ratio ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

Ground granulated blast furnace slag (GGBFS) conventionally has been incorporated with ordinary Portland cement (OPC) owing to reduce the environmental load and enhance the engineering performance. Concrete with GGBFS shows different strength development of normal concrete, but sensitive, to exterior condition. Thus, a precise strength evaluation technique based on a quantitative model like full maturity model is required. Many studies have been performed on strength development of the concrete using equivalent age which is based on the apparent activation energy. In this process, it considers the effect of time and temperature simultaneously. However, the previous models on the apparent activation energy of concrete with mineral admixtures have limitation, and they have not considered the effect of temperature on strength development. In this paper, the apparent activation energy with GGBFS replacement ratio was calculated through several experiments and used to predict the compressive strength of GGBFS concrete. Concrete and mortar specimens with 0.6 water/binder ratio, and 0 to 60% GGBFS replacement were prepared. The apparent activation energy (Ea) was experimentally derived considering three different curing temperatures. Thermodynamic reactivity of GGBFS mixed concrete at different curing temperature was applied to evaluate the compressive strength model, and the experimental results were in good agreement with the model. The results show that when GGBFS replacement ratio was increased, there was a delay in compressive strength.

Effect of the Combined Using of Fly Ash and Granulated Blast Furnace Slag on Properties of Cementless Alkali-Activated Mortar

2011 ◽  
Vol 287-290 ◽  
pp. 916-921
Author(s):  
Kyung Taek Koh ◽  
Gum Sung Ryu ◽  
Si Hwan Kim ◽  
Jang Hwa Lee
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Curing Temperature ◽  
Mixture Ratio ◽  
Granulated Blast Furnace Slag ◽  
Alkaline Activator ◽  
Furnace Slag ◽  
Alkali Activated

This paper examines the effects of the mixture ratio of fly ash/slag, the type of alkaline activators and curing conditions on the workability, compressive strength and microstructure of cementless alkali-activated mortar. The investigation showed that the mixture ratio of fly ash/slag and the type of alkaline activator have significant influence on the workability and strength, whereas the curing temperature has relatively poor effect. An alkali-activated mortar using a binder composed of 50% of fly ash and 50% of granulated blast furnace slag and alkaline activator made of 9M NaOH and sodium silicate in proportion of 1:1 is seen to be able to develop a compressive strength of 65 MPa at age of 28 days even when cured at ambient temperature of 20°C.

Optimization of Concrete Porous Mix Using Slag as Substitute Material for Cement and Aggregates

2017 ◽  
Vol 865 ◽  
pp. 282-288 ◽  
Author(s):  
Jul Endawati ◽  
Rochaeti ◽  
R. Utami
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Silica Fume ◽  
Blast Furnace Slag ◽  
Environmental Effect ◽  
Substitution Effect ◽  
Main Concern ◽  
Binder Material ◽  
Furnace Slag

In recent years, sustainability and environmental effect of concrete became the main concern. Substituting cement with the other cementitious material without decreasing mechanical properties of a mixture could save energy, reduce greenhouse effect due to mining, calcination and limestone refining. Therefore, some industrial by-products such as fly ash, silica fume, and Ground Iron Blast Furnace Slag (GIBFS) would be used in this study to substitute cement and aggregate. This substitution would be applied on the porous concrete mixture to minimize the environmental effect. Slag performance will be optimized by trying out variations of fly ash, silica fume, and slag as cement substitution material in mortar mixture. The result is narrowed into two types of substitution. First, reviewed from the fly ash substitution effect on binder material, highest compressive strength 16.2 MPa was obtained from mixture composition 6% fly ash, 3% silica fume and 17% grinding granular blast-furnace slag. Second, reviewed from slag types as cement substitution and silica fume substitution, highest compressive strength 15.2 MPa was obtained from mortar specimens with air-cooled blast furnace slag. It composed with binder material 56% Portland composite cement, 15% fly ash, 3% silica fume and 26% air-cooled blast furnace slag. Considering the cement substitution, the latter mixture was chosen.

scholarly journals Protective Geopolymer Coatings Containing Multi-Componential Precursors: Preparation and Basic Properties Characterization

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3448
Author(s):  
Chenhui Jiang ◽  
Aiying Wang ◽  
Xufan Bao ◽  
Zefeng Chen ◽  
Tongyuan Ni ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Fly Ash ◽  
Portland Cement ◽  
Adhesive Strength ◽  
Blast Furnace Slag ◽  
Setting Time ◽  
Rapid Test ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This paper presents an experimental investigation on geopolymer coatings (GPC) in terms of surface protection of civil structures. The GPC mixtures were prepared with a quadruple precursor simultaneously containing fly ash (FA), ground granulated blast-furnace slag (GBFS), metakaolin (MK), and Portland cement (OPC). Setting time, compressive along with adhesive strength and permeability, were tested and interpreted from a perspective of potential applications. The preferred GPC with favorable setting time (not shorter than 120 min) and desirable compressive strength (not lower than 35 MPa) was selected from 85 mixture formulations. The results indicate that balancing strength and setting behavior is viable with the aid of the multi-componential precursor and the mixture design based on total molar ratios of key oxides or chemical elements. Adhesive strength of the optimized GPC mixtures was ranged from 1.5 to 3.4 MPa. The induced charge passed based on a rapid test of coated concrete specimens with the preferred GPC was 30% lower than that of the uncoated ones. Setting time of GPC was positively correlated with η[Si/(Na+Al)]. An abrupt increase of setting time occurred when the molar ratio was greater than 1.1. Compressive strength of GPC was positively affected by mass contents of ground granulated blast furnace slag, metakaolin and ordinary Portland cement, and was negatively affected by mass content of fly ash, respectively. Sustained seawater immersion impaired the strength of GPC to a negligible extent. Overall, GPC potentially serves a double purpose of satisfying the usage requirements and achieving a cleaner future.

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