Surface area and pore structure of hydrothermal reaction products of granulated blast furnace slag

1978 ◽  
Vol 8 (2) ◽  
pp. 151-160 ◽  
Author(s):  
S.A. Abo-El-Enein ◽  
R.Sh. Mikhail ◽  
M. Daimon ◽  
R. Kondo
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.


1984 ◽  
Vol 42 ◽  
Author(s):  
Della M. Roy ◽  
G. M. Idorn

AbstractSubstantial increases of the strength of cement paste and mortars may be obtained in conventional processing by optimizing the materials components, the rheology and the curing, and thereby improving the microstructures. Cementitious materials with high proportions of granulated blast-furnace slag have been investigated. Higher strengths of ASTM C 109 mortars were obtained with 40 to 65% substitution of portland cement by slag, than with ordinary mix compositions and processing.For one set of mixtures, 28 day strengths ≥ 100 MPa (some as high as 240 MPa) were consistently attained after curing at temperatures ranging from 27 to 250°C. The slag substitutions developed finer pore structures as revealed by intrusion porosimetry measurements, than those with pure portland cement. This is believed to be a major reason for their enhanced durability. At each stage from 3 to 28 days, increase of curing temperatures from 27 to 90°C decreased porosity and increased the strength, reflecting an increased maturity.Implications for practice and suggestions for further work are discussed.


2014 ◽  
Vol 687-691 ◽  
pp. 4187-4191
Author(s):  
Guang Hui Cheng ◽  
Yuan Song

The change of the specific surface area, particle size and activity index of ground granulated blast furnace slag under different grinding conditions is researched based on closed-circuit mill in the paper. The research shows that the grinding effect is greatly different with the different grinding body, and proper pre-grinding time can help to improve the grinding effect. The optimum plan in this paper is as follow: pre-grinding 15 min at steel bar then grinding 30 min at ball grinding, and it will getting the maximum specific surface area, the smallest powder particle size and the the maximum activity index.


2014 ◽  
Vol 578-579 ◽  
pp. 1430-1440 ◽  
Author(s):  
Joon Woo Park ◽  
Sung In Hong ◽  
Hee Jun Yang ◽  
Thamara Tofeti Lima ◽  
Ki Yong Ann

The present study concerns a development of cement-free concrete using ground granulated blast-furnace slag (GGBS) with alkali-activators such as KOH, NaOH, and Ca (OH)2. To find out the development among three different activators, the concentration of hydroxyl ion was kept 0.5%, 1.0%, 1.5%, 2.0% and 3.0% by weight of binder irrespective of cations. The setting time was measured by penetration resistance immediately after casting of mortar. The development of compressive strength was measured at 7, 14, 28, and 91 days. The pore structure of cement-free mortar was examined by the mercury intrusion porosimetry (MIP) and rapid chloride penetration test (RCPT). Simultaneously, grew sample was used to microscopically observe at the XRD. For strength of cement-free mortar, mixed with KOH or NaOH was as high as OPC at 3.0 % by weight of binder. However, the compressive strength of cement-free concrete mixed with 3.0 % Ca (OH)2 by weight of binder had just half strength of OPC mortar. Cement-free concrete activated with NaOH and Ca (OH)2 had higher total pore volume, however, it had lower ionic penetrability due to the pore type which mostly consist of gel pores. For pore structure of cement-free mortar mixed with KOH, the total volume had similarity to that of OPC mortar, however, it had lower penetrability. Therefore, it may have higher resistance to chloride transport than that of OPC mortar.


2011 ◽  
Vol 194-196 ◽  
pp. 924-929
Author(s):  
Jian Xiong Ye ◽  
Ye Jiang Wang ◽  
Shuang Zhao ◽  
Ming Chao Yang ◽  
Chang Hui Yang

The permeability resistance of concrete with ground phosphate slag(GPS) against chloride ion penetration was tested according to ASTM1202 and by nitrogen adsorption method. Test results show that by adding ground phosphate slag to concrete, the chloride diffusion coefficient of concrete decreases, and the permeability resistance of concrete against chloride ion penetration increases with improvement of its pore structure. The pores in concrete are refined and the percentage of the pores with diameter less than 20nm in concrete increases. The improvement of pore structure of the concrete by ground phosphate slag is much better than that by the ground granulated blast furnace slag or fly ash, while the addition is 30 percent. The ability of additive to improve the permeability resistance of concrete against chloride ion penetration is in following order: fly ash > ground phosphate slag > ground granulated blast furnace slag.


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