Influence of Sulphides on Hydration of Ground Granulated Slag Alkali Activated Mortars and Pastes

2018 ◽  
Vol 761 ◽  
pp. 92-95
Author(s):  
Łukasz Kotwica ◽  
Ewa Kapeluszna ◽  
Piotr Stępień ◽  
Jan Deja ◽  
Mirja Illikainen ◽  
...  
Keyword(s):  
Basal Spacing ◽  
Flow Density ◽  
Sodium Sulphide ◽  
Early Hydration ◽  
Granulated Blast Furnace Slag ◽  
Sulphide Ions ◽  
Granulated Slag ◽  
Activated Slag ◽  
Furnace Slag ◽  
Reducing Properties

Influence of sodium sulphide on properties of sodium hydroxide activated ground granulated blast furnace slag was investigated. Properties of both fresh (cone flow, density) as well as hardened (compressive strength) mortars were determined. Early hydration of pastes was investigated using conducting calorimetry. Results showed, that introduction of sodium sulphide to caustic soda activated slag only slightly influence the course of hydration process. Early strength is increased by about 10%. In later periods strength is virtually not affected by the presence of sodium sulphide. Those observations are confirmed by calorimetric results. Presence of sodium sulphide causes slight decrease in consistency of mortars. Colour of mortars is also affected by the presence of sulphides. It is more darker and it is most probably due to the reducing properties of sulphide ions. Results of model investigations on precipitated C-S-H phase showed, that presence of sulphides results in increased main basal spacing of C-S-H phase as determined by XRD.

Influence of Calcined Mine Tailings on the Properties of Alkali Activated Slag Mortars

2018 ◽  
Vol 761 ◽  
pp. 83-86 ◽  
Author(s):  
Łukasz Kotwica ◽  
Marcin Chorembała ◽  
Ewa Kapeluszna ◽  
Piotr Stępień ◽  
Jan Deja ◽  
...  
Keyword(s):  
Mine Tailings ◽  
Pozzolanic Activity ◽  
Partial Substitution ◽  
Copper Mine ◽  
Copper Mine Tailings ◽  
Granulated Blast Furnace Slag ◽  
Granulated Slag ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

Influence of copper mine tailings on properties of soda activated ground granulated blast furnace slag mortars and pastes was investigated. Calcination of copper mine tailings was found to be a method of increasing their pozzolanic activity. Material calcined at 750°C possessed highest pozzolanic activity. So obtained material can be used as a partial substitution of ground granulated slag in soda activated blends. Introduction of calcined copper mine tailings decrease strength up to 28 days, but after 56 days strength results are similar or even higher comparing to control samples. Phase composition of hydrated material is not affected significantly by the presence of calcined copper mine tailings.

scholarly journals Gypsum-Dependent Effect of NaCl on Strength Enhancement of CaO-Activated Slag Binders

2018 ◽  
Vol 8 (12) ◽  
pp. 2515 ◽  
Author(s):  
Sungwon Sim ◽  
Hwan Lee ◽  
Dongho Jeon ◽  
Haemin Song ◽  
Woo Yum ◽  
...  
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Binder System ◽  
Sulfate Ions ◽  
Dependent Effect ◽  
Strength Enhancement ◽  
Granulated Blast Furnace Slag ◽  
Significant Strength ◽  
Activated Slag ◽  
Furnace Slag

This study explores the combined effect of NaCl and gypsum on the strength of the CaO-activated ground-granulated blast furnace slag (GGBFS) binder system. In the CaO-activated GGBFS system, the incorporation of NaCl without gypsum did not improve the strength of the system. However, with the presence of gypsum, the use of NaCl yielded significantly greater strength than the use of either gypsum or NaCl alone. The presence of NaCl largely increases the solubility of gypsum in a solution, leading to a higher concentration of sulfate ions, which is essential for generating more and faster formations of ettringite in a fresh mixture of paste. The significant strength enhancement of gypsum was likely due to the accelerated and increased formation of ettringite, accompanied by more efficient filling of pores in the system.

scholarly journals The Effects of Aluminium Sulphate on Slag Paste Activated with Sodium Hydroxide and Sodium Silicate

Materials ◽  
2020 ◽  
Vol 13 (10) ◽  
pp. 2286
Author(s):  
Taewan Kim ◽  
Sungnam Hong ◽  
Choonghyun Kang
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Sodium Hydroxide ◽  
Blast Furnace Slag ◽  
Aluminium Sulphate ◽  
The Third ◽  
Granulated Blast Furnace Slag ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

This study investigates the characteristics of alkali-activated slag cement using aluminium sulphate (ALS) as an activator. The alkalis NaOH and Na2SiO3 were used as additional activators (denoted by alkali) at 5% and 10% of the weight of the ground granulated blast furnace slag (GGBFS). Three types of activators were considered. The first was when ALS was used alone. For the second, ALS and 5% alkali were used together. The third was when ALS and 10% alkali were used. ALS was used at concentrations of 2%, 4%, 6%, 8%, and 10% based on binder weight. Experimental results show that when ALS was used as a sole activator, the activity of GGBFS was low and its strength was below 1 MPa. However, compressive strength was improved when 5% or 10% alkali and ALS were used at the same time. This was effective at improving mechanical and microstructural performance when used with an additional activator capable of forming a more alkaline environment than using ALS as a sole activator.

Effect of Sodium Hydroxide (NaOH) Concentration on Compressive Strength of Alkali-Activated Slag (AAS) Mortars

2015 ◽  
Vol 754-755 ◽  
pp. 300-304 ◽  
Author(s):  
Aimi Noorliyana Hashim ◽  
Kamarudin Hussin ◽  
Noorzahan Begum ◽  
Mohd Mustafa Al Bakri Abdullah ◽  
Kamrosni Abdul Razak ◽  
...  
Keyword(s):  
Compressive Strength ◽  
Blast Furnace ◽  
Sodium Hydroxide ◽  
Blast Furnace Slag ◽  
Alkali Activated Slag ◽  
Granulated Blast Furnace Slag ◽  
Environmental Friendly ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

Energy saving in building technology is among the most critical problems in the world. Thus it is a need to develop sustainable alternatives to conventional concrete utilizing more environmental friendly materials. One of the possibilities to work out is the massive usage of industrial wastes like ground granulated blast furnace slag (GGBS) to turn them to useful environmental friendly and technologically advantageous cementitious materials. In this study, ground granulated blast furnace slag (GGBS) is used to produce of alkali activated slag (AAS) mortar with the effect of alkaline activator concentration. Alkali activated slag (AAS) mortar is accelerated using alkaline solution of sodium silicate mixed with sodium hydroxide. The fixed ratio of sodium silicate to sodium hydroxide is 1.7 and the concentration of sodium hydroxide is varied from 6M to 12M. Concentration of 10M NaOH promotes the best properties of mortar by achieving the greatest compressive strength. Substitution of mineral admixture also influences strength performance of AAS mortars. The mortar with 20% calcium carbonate demonstrates the maximum compressive strength. The used of alkaline activation system is the best method to prepare industrial byproduct concrete. Moreover, alkali activated product itself gains superior properties which lead to the system become the most interesting method to produce sustainable concrete.

Complex Shrinkage-Reducing Additives for Alkali Activated Slag Cement Fine Concrete

2021 ◽  
Vol 321 ◽  
pp. 165-170
Author(s):  
Pavlо Krivenko ◽  
Volodimir I. Gots ◽  
Oleh Petropavlovskyi ◽  
Igor Rudenko ◽  
Oleksandr Konstantynovskyi
Keyword(s):  
Cement Clinker ◽  
Reinforcement Corrosion ◽  
Sodium Gluconate ◽  
Slag Cement ◽  
Alkali Activated Slag ◽  
Granulated Blast Furnace Slag ◽  
Portland Cement Clinker ◽  
Activated Slag ◽  
Furnace Slag ◽  
Alkali Activated

Optimization of complex shrinkage-reducing additives (further, SRA’s), consisting of ordinary portland cement clinker (further, OPC clinker), salt-electrolyte and surfactants, is provided for prevention of steel reinforcement corrosion due to shrinkage mitigation in alkali-activated slag cement (further, AASC) fine concrete. Modification of AASC by SRA included 0.3 % sodium lignosulphonate, 0.15 % sodium gluconate, 1.4 – 2.0 % NaNO3 and 6.5 - 7.7 % OPC clinker (by mass of granulated blast furnace slag) provides shrinkage reduction from 0.984 up to 0.560 – 0.605 mm/m (t=202 °С, R.H.=65 %). Unlike, SRA presented by the mentioned system with 1.50 - 1.59 % Na2SO4 and 4.0 - 4.65 % OPC clinker causes shrinkage mitigation from down to 0.625 - 0.640 mm/m. In addition, SRA with 1.80 - 2.05 % Na3PO4 and 4.0 - 4.6 % OPC clinker minimizes shrinkage to 0.713 - 0.700 mm/m. Shrinkage mitigation in modified AASC fine concrete is explained by less water, higher crystallinity of hydrated phases as well as by formation of minamiit (Na,Ca0.5)Al3(SO4)2(OH)6, calcium hydronitroaluminate ЗСаО∙А12О3∙Са (NO3)2∙10Н2О and calcium hydroxylapatite Са10(РО4)6(ОН)2 crystals versus salt-electrolyte, i.e. Na2SO4, NaNO3 and Na3PO4 agreeably. The 28 day compressive strength of modified AASC fine concrete is not less than the reference one (48.0 - 56.0 МPа).

scholarly journals INTERACTION OF MOLTEN SLAG WITH SOLID PHASE OF RED SLUDGE

2019 ◽  
Vol 62 (4) ◽  
pp. 276-282
Author(s):  
A. B. Lebedev ◽  
V. A. Utkov ◽  
E. M. Gutema
Keyword(s):  
Solid Phase ◽  
Road Construction ◽  
Cooling Liquid ◽  
Granulated Blast Furnace Slag ◽  
Urgent Task ◽  
Engineering And Technology ◽  
Treatment Equipment ◽  
Granulated Slag ◽  
Furnace Slag ◽  
Active Interaction

Granulated blast furnace slag is steadily used in large quantities in production of cements, in road construction, agriculture and in other areas of engineering and technology. Peculiarity of its production process is active interaction of molten metallurgical slag with cooling liquid. Simultaneously and instantly, slag solidifies and the mass of the latter breaks up in the atmosphere of hot steam into small particles due to critical stresses occurring. The problem is that during granulation of slags, usually containing sulfur, large amount of harmful substances (sulfur oxide and hydrogen sulfde) is released into the atmosphere. Its concentration at work sites - sites of granulation many times exceeds the MPC. To combat this phenomenon, finely dispersed, expensive lime or limestone is introduced into the composition of cooling liquid. This is associated with high costs for the construction of crushing, grinding and dust treatment equipment. In addition, placement of such equipment is hampered by the lack of free space in the blast furnaces. In this work, it is shown that lime and limestone can be replaced by fine red mud (RM), a waste from the production of alumina from bauxite. This material also has properties of absorption of sulfur compounds from the gas phase. The problem of its processing is also an urgent task. At present, RM is located in sludge storage facilities that are harmful to environment, and destruction of the enclosing dam leads to an environmental catastrophe (Hungary, 2010). This article presents the results of study of RM use. Sorption properties of RM of 6 plants were studied under laboratory conditions. The samples of granulated slag obtained in the process of interaction with RM were investigated. Laboratory and industrial tests were conducted. It was found that with its help, concentration of sulfur gases at granulation work sites can be reduced by twice. It is important that the new granulated slag, called “sludge-slag” in this case, is not inferior to the usual one by its basic technological properties.

scholarly journals ABOUT THE POSSIBILITY OF APPLICATION OF GRIND BLAST FURNACE GRANULATED SLAG PJSC “SEVERSTAL” IN CEMENT SYSTEMS

2020 ◽  
Author(s):  
Н.Н. Калиновская ◽  
К.С. Аль-Мусави ◽  
Д.В. Кузнецов
Keyword(s):  
Blast Furnace ◽  
Blast Furnace Slag ◽  
Bending Strength ◽  
Point Of View ◽  
Iron And Steel ◽  
Granulated Blast Furnace Slag ◽  
Granulated Slag ◽  
Iron And Steel Works ◽  
Water Holding ◽  
Furnace Slag

В металлургическом производстве образуются технологические отходы (шлаки, шламы, пыль, окалина и другие), количество которых исчисляется в сотнях миллионов тонн. Одним из наиболее распространенных металлургических отходов является доменный гранулированный шлак, который при помоле приобретает гидравлические свойства и может использоваться как компонент вяжущего для цементных систем. Приведены результаты исследования свойств доменного шлака ПАО «Северсталь» (г. Череповец, РФ), а именно химический и фазовый состав предоставленных образцов шлака, а также индекс его активности по EN 15167 в зависимости от тонкости помола. На данном этапе исследований шлака не видится препятствий для использования шлака ПАО «Северсталь» в качестве компонента вяжущего в цементных системах. Показано, что с точки зрения прочности на сжатие и изгиб, а также расплыва стандартного конуса, который косвенно характеризует водоудерживающую способность вяжущего, предпочтительной является тонкость помола Sуд = 3 500…4 000 см2/г. Использование вяжущего, состоящего на 100 % из шлака, нецелесообразно без применения активатора. In the process of enrichment and smelting of metals, technological wastes (slags, sludge, dust, scale and others) are generated, the amount of which is calculated in hundreds of millions of tons. One of the local metallurgical waste is granulated blast-furnace slag, which, after grinding, acquires the hydraulic properties and can be used as a component of a binder. The results of studying the properties of blast-furnace slag of Severstal Iron and Steel Works (Cherepovets, Russia), namely the chemical and phase composition of the provided slag samples, as well as the index of its activity according to EN 15167, depending on the fineness of grinding are presented. At this stage of slag research, there are no obstacles to using slag from Severstal as a binder component in cement systems. It is shown that from the point of view of compressive and bending strength, as well as the spreading of a standard cone, which indirectly characterizes the water-holding capacity of the binder, the fineness of grinding 3500...4000 cm2/g is preferable. The use of a binder consisting of 100 % slag is not recommended without the use of an activator.

scholarly journals Surface Characteristics of Portland Cement/Blast Furnace Slag Mixtures

1996 ◽  
Vol 13 (6) ◽  
pp. 461-467 ◽  
Author(s):  
Kh.A. Khalil
Keyword(s):  
Blast Furnace ◽  
Portland Cement ◽  
Blast Furnace Slag ◽  
Surface Characteristics ◽  
Hydration Products ◽  
Cement Pastes ◽  
Degree Of Hydration ◽  
Granulated Blast Furnace Slag ◽  
Granulated Slag ◽  
Furnace Slag

The effect of the degree of hydration and amounts of granulated blast furnace slag on the surface properties of Portland cement pastes were studied. The results obtained showed that the specific surface area SBET (m2/g) and pore volume Vp (cm3/g) decreased on increasing the degree of hydration. The addition of different amounts of granulated slag effected a decrease in SBET and Vp to an extent proportional to the amount present. These results were attributed to a replacement of clinker by the amounts of slag added and the formation of hydration products.

ESTUDO DE VIABILIDADE TÉCNICA DA APLICAÇÃO DA ESCÓRIA GRANULADA DE ALTO-FORNO EM SUBSTITUIÇÃO AO AGREGADO MIÚDO NA COMPOSIÇÃO DO CONCRETO

2021 ◽  
Vol 17 (2) ◽  
pp. 47-69
Author(s):  
Anderson Buss Woeffel ◽  
Matheus Laureth Batista
Keyword(s):  
Blast Furnace ◽  
Raw Materials ◽  
Fine Aggregate ◽  
Unsatisfactory Result ◽  
Granulated Blast Furnace Slag ◽  
Fresh State ◽  
Hardened State ◽  
Granulated Slag ◽  
Social Environmental ◽  
Furnace Slag

The macro sector of the civil construction industry is a major consumer of natural resources and it generates impacts, identified as social, environmental or economic, and it is necessary to develop studies that aim to rationalize this raw materials consumption and reduce the impacts generated. Since some resources used in the sector are finite, this work’s main objective is to make the concrete more ecological by replacing part of the fine aggregate of its composition for granulated slag from the blast furnace, reducing the need for sand extraction. For this study, tests were carried out with the co-product and with the fine aggregate, evaluating the properties of the concrete in the fresh and hardened states in three mixture types, the first being a reference, the second with 30% replacement and the third with 60% replacement of fine aggregate with slag. Based on the results obtained, it is noted that the granulated blast furnace slag has more similar characteristics to the sand’s; in the fresh state, the concrete showed a similar result in the three mix types; in the hardened state, it was observed that the performance of the concrete in axial compression was satisfactory; while in flexion traction the two proposed mixtures with substitution presented an unsatisfactory result.

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