scholarly journals Control of the setting reaction and strength development of slag-blended volcanic ash-based phosphate geopolymer with the addition of boric acid

2021 ◽  
Author(s):  
Jean Noël Yankwa Djobo ◽  
Dietmar Stephan
Keyword(s):  
Blast Furnace ◽  
Boric Acid ◽  
Blast Furnace Slag ◽  
Volcanic Ash ◽  
Strength Development ◽  
Main Process ◽  
Reaction Products ◽  
Setting Times ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

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.

scholarly journals Influence of Calcium Sulfate Type on Evolution of Reaction Products and Strength in NaOH- and CaO-Activated Ground Granulated Blast-Furnace Slag

2018 ◽  
Vol 8 (12) ◽  
pp. 2500 ◽  
Author(s):  
Seyoon Yoon ◽  
Hyeoneun Park ◽  
Woo Yum ◽  
Jung-Il Suh ◽  
Jae Oh
Keyword(s):  
Blast Furnace ◽  
Pore Volume ◽  
Blast Furnace Slag ◽  
Calcium Sulfate ◽  
Effective Means ◽  
Strength Development ◽  
Reaction Products ◽  
Beneficial Effects ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

This study investigated the influences of CaSO4 type (i.e., anhydrite vs. gypsum) on strength development and reaction products in the activation of ground granulated blast-furnace slag (GGBFS) when different activators (i.e., CaO vs. NaOH) and sources of GGBFS were used. In the CaO-activation, the addition of calcium sulfates greatly enhanced 28-day strengths, regardless of the choice of CaSO4 or GGBFS source, through increasing the quantities of reaction products and reducing pore volume and size. However, in the NaOH-activation, the use of calcium sulfates showed the complex dependency of strength on the choice of CaSO4 type and GGBFS source, and it barely produced beneficial effects on the quantity of reaction products and reduction of pore volume and size. Thus, the results in this study indicate that the combination of CaO-activation and calcium sulfates is a more effective means of activating GGBFS to gain enhanced strength and significant quality control than the use of gypsum with NaOH-activation.

Effect of Ground Granulated Blast Furnace Slag on Compressive Strength of POFA Blended Concrete

2015 ◽  
Vol 802 ◽  
pp. 142-148
Author(s):  
M.N. Noor Azline ◽  
Farah Nora Aznieta Abd Aziz ◽  
Arafa Suleiman Juma
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Strength Development ◽  
Replacement Level ◽  
Concrete Compressive Strength ◽  
Cement Replacement ◽  
Granulated Blast Furnace Slag ◽  
Strength Tests ◽  
Furnace Slag

The article reports a laboratory experimental programme that investigated effect of ground granulated blast furnace (GGBS) on compressive strength of POFA ternary concrete. Compressive strength tests were performed at a range of cements combinations, including 100%PC, two POFA levels for binary concrete, 35% and 45%, and 15%GGBS inclusion for POFA ternary concrete. The compressive strength results were examined in comparison to PC only and equivalent POFA binary concretes for up to 28 days. Results show that the reduction in compressive strength is greater with the higher cement replacement level for all concretes particularly for POFA binary concretes. However, 15%GGBS in POFA blended concrete has a comparable compressive strength compared to PC concrete at both, 35% and 45%, cement replacement levels except for ternary concrete at 0.65 w/c. In addition, the compressive strength of ternary concrete is slightly higher compared to binary concrete for all concrete combinations. Although there is no significant noticeable influence on strength development, the presence of GGBS did not adverse the strength development of POFA blended concrete. Thus, it can be concluded that GGBS compensates the adverse effect of POFA at early strength development.

scholarly journals Early Strength Development of Soft Clay Stabilized by One-Part Ground Granulated Blast Furnace Slag and Fly Ash-Based Geopolymer

2021 ◽  
Vol 8 ◽  
Author(s):  
Xiyao Zheng ◽  
Jun Wu
Keyword(s):  
Blast Furnace ◽  
Fly Ash ◽  
Blast Furnace Slag ◽  
Soft Clay ◽  
Strength Development ◽  
Granulated Blast Furnace Slag ◽  
Binder Ratio ◽  
Early Strength ◽  
Furnace Slag ◽  
Water Binder Ratio

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.

Strength development of solely ground granulated blast furnace slag geopolymers

2020 ◽  
Vol 250 ◽  
pp. 118720 ◽  
Author(s):  
Ikmal Hakem Aziz ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
M.A.A. Mohd Salleh ◽  
Emy Aizat Azimi ◽  
Jitrin Chaiprapa ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Strength Development ◽  
Granulated Blast Furnace Slag ◽  
Furnace Slag

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.

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