scholarly journals Maturity and Strength Development of Mortar with Antifreezing Admixture at Temperatures Lower than 0 °C

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3172
Author(s):  
Hyeonggil Choi ◽  
Yukio Hama ◽  
Madoka Taniguchi

This study investigated the effect of temperature and time at temperatures lower than 0 °C on mortar mixed with antifreezing admixture to determine the temperature–time function with the aim of expressing the effect universally. As a result, the maturity equation for temperatures lower than 0 °C proposed in previous studies was verified to be applicable to type-B blast furnace slag cement. The applicability of this equation at temperatures lower than 0 °C had not been investigated hitherto. The strength development attributable to the effect of the antifreezing admixture can be expressed as the reference temperature, and the reduction in the chemical potential of water chemical potential reduction was found to depend on the reaction rate. A new maturity equation for temperatures lower than 0 °C was proposed considering the effect of the antifreezing admixture.

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.


2017 ◽  
Vol 71 (1) ◽  
pp. 308-314
Author(s):  
Shingo YOSHIMOTO ◽  
Tatsuo SHINMI ◽  
Hiroyoshi KATO ◽  
Takatoshi MOTOORI

2015 ◽  
Vol 802 ◽  
pp. 142-148
Author(s):  
M.N. Noor Azline ◽  
Farah Nora Aznieta Abd Aziz ◽  
Arafa Suleiman Juma

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.


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.


2017 ◽  
Vol 265 ◽  
pp. 631-635
Author(s):  
N.A. Eroshkina ◽  
M.O. Korovkin

The influence of various factors on the hardening kinetics of composite geopolymer binders based on the milled waste of magmatic rock production and processing has been investigated. The type and dosage of the binder mineral additives - granulated blast-furnace slag and fly ash - as well as the composition of the hardening activator, component dispersion, and hardening temperature have been studied as the factors determining the rate of strength development. Some analytical dependencies describing the influence of the examined factors on the strength of geopolymer magmatic rock-based binders have been developed. The dependencies developed were used to establish the requirements for process conditions of the geopolymer construction products and structures production.


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