2 edition of Fly ash increases resistance of concrete to sulfate attack. found in the catalog.
Fly ash increases resistance of concrete to sulfate attack.
J. T. Dikeou
|Series||Water resources technical publications. Research report -- no.23|
|Contributions||United States. Bureau of Reclamation.|
Even though some contradictory results have been reported, most studies indicate that the use of suitable amount of Class C fly ash in concrete can improve its resistance to sulfate attack and alkali-silica reaction Several investigatorsl10l reported that concrete which used fly ash had satisfactory resistance to the freeze-thaw attack. Non-hazardous waste materials and by-products which are mostly landfilled, can be used in making concrete and similar construction materials. This book gives an summary of this usage: one chapter is devoted to each material, comprising an introduction, chemical and physical properties, usage potential, and the impact of the material on the various properties of concrete.
Durability of concrete containing fly ash (FA) and silica fume (SF) against combined freezing-thawing and sulfate attack was studied in this paper. Concretes with w/b of and containing FA (i.e. of 10%, 15% and 25% by weight) and SF (i.e. of 5%, 8% and 11% also by weight) as partial replacement of Portland cement (PC) were exposed to 5% and 10% sodium sulfate solution under freezing. The study shows that good sulfate-resistant RCCs can be attained with the use of Type V portland cement with or without low-calcium fly ash. The resistance to sulfate attack improves with increases in cement or coarse aggregate content, as concrete becomes more dense and impermeable.
materials (SCMs) such as fly ash and metakaolin (ASTM C), slag 2 Sulfate exposure Sulfate (SO 4) in soil, % by mass Sulfate (SO periods increase resistance to corrosive substances by increasing The rate of attack on concrete may be directly related to the activity. amount of fly ash and silica fume on the resistance of concrete to sulfate attack. The compositions of concrete mixture with various w/c are listed in Table 2. Based on A3 serial concrete mixture sample, samples of cement replacement with fly ash of 15%, 25% and.
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Class F Fly Ash INCREASES RESISTANCE TO SULFATE ATTACK Sulfate Attack Is A Two-Phased Process Sulfates combine with calcium hydroxide generated during cement hydration to form calcium sulfate (gypsum). Additional Physical Format: Online version: Dikeou, James T.
Fly ash increases resistance of concrete to sulfate attack. Washington, D.C.: United States Department of. FLY ASH INCREASES RESISTANCE TO SULPHATE ATTACK Soluble sulphates which exist in soils, ground waters and sewage waste corrode and eventually destroy Portland cement concrete unless it is designed with fly ash to maximise sulphate resistance.
SULPHATE ATTACK Sulphate attack is a two-phased process: 1. The replacements of Portland cement by the assigned percentages of fly ash have significantly increased the resistance of SCC to the external sulfate attack due Cited by: 1.
It was observed from the results that low volume carbonated fly ash concrete demonstrated a significant increase in resistance to loss in compressive strength and weight against salt, sulfate, and acid by: The effects of fly ash on the sulfate attack of mortars were analyzed.
Results indicated that the addition of fly ash improved the resistance of sulfate attack significantly, this probably. Fly ash also improves the resistance of concrete to Na 2 SO 4 attack. This effect is not simply the consequence of dilution of PC, since replacement with sand increases expansion.
Unlike PC, whose sulfate resistance is relatively insensitive to the duration of curing, the effectiveness of fly ash is highly dependent on curing time, with longer curing periods yielding higher resistance. Durability of concrete containing fly ash (FA) and silica fume (SF) against combined freezing-thawing and sulfate attack was studied in this paper.
Concretes with w/b of and containing FA (i.e. of 10%, 15% and 25% by weight) and SF (i.e. of 5%, 8% and 11% also by weight) as partial replacement of Portland cement (PC) were exposed to 5. The incorporation of pozzolans such as fly ash imparts benefits to concrete such as reduced permeability, increased resistance to alkali silica reaction (ASR), sulfate attack, chloride ingress and corrosion.
It has long been recognized that the activity of fly ash is much improved by increasing. Boral Resources offers a wide variety of pozzolans to improve concrete performance during placement and throughout the life of the project.
Boral is a major source of the most commonly used pozzolan, Fly Ash, produced from the combustion of coal in power generating plants. Fly ash increases resistance of concrete to sulfate attack (Book, )  Get this from a library. Fly ash increases resistance of concrete to sulfate attack.
the fly ash will be in terms of reducing the heat of hydration (Thomas ), controlling expansion due to alkali-silica reaction (Shehata ), and providing resistance to sulfate attack (Shashiprakash ).
These issues are addressed in sections Effect of Fly Ash on. A high percentage of CaO in fly ash may accelerate the sulfate problem substantially.
For instance, ASTM Class F fly ash with resistance of concrete to sulfate attack. Similarly, silica fume, metakaolin and natural pozzolans consume Ca to improve sulfate resistance.
The sulfate resistance of concrete containing fly ash was found to be related to the composition of the noncrystalline glassy phases of the fly ash. Concrete containing low calcium fly ash was found to have a. Some fly ashes increased the resistance of concrete to sulfate attack, whereas other sources of fly ash accelerated the rate of damage due to sulfate attack.
A 2-step evaluation procedure is proposed to assist in selecting of fly ash sources for concrete that may be exposed to a sulfate environment.
Some authors studied the effect of fly ash on the resistance of concrete/mortar to sulfate attack and pointed out that using sufficient amount of fly ash, especially low-calcium or F class fly ash.
Among these are high resistance to alkali-silica reaction; superior acid resistance; and high resistance to fire, low carbonation and limited sulfate attack, says Naghizadeh. Fly ash geopolymer cement is suitable mostly for precast concrete manufactured at a factory or workshop.
It is the physical resistance to penetrate into the concrete of all liquids, by reducing the water/binder ratio, and adequately consolidating and curing the concrete Control of sulphate attack • The quality of concrete, specifically a low permeability, is the best protection against sulphate attack.
Pre-stressed high-strength concrete piles (PHCP) are widely used in the building industry in China. The main aim of our research was to investigate the utilization of quartz powder, fly ash, and blast furnace slag as mineral additives to prepare PHCP mortar.
The samples were prepared using steam and autoclaving steaming. The influence of minerals on the sulfate resistance of mortar was. The American Concrete Institute. Founded in and headquartered in Farmington Hills, Michigan, USA, the American Concrete Institute is a leading authority and resource worldwide for the development, dissemination, and adoption of its consensus-based standards, technical resources, educational programs, and proven expertise for individuals and organizations involved in concrete design.
These sulfate resistance test results indicate that the R-value remains a good indicator of potential sulfate resistance of fly ash concretes.
When concrete contains 15 to 25 percent fly ash with an R-value less than the sulfate resistance will be equal or better than a. Metakaolin in concrete tends to reduce the size of pores, which, consequently, leads to higher density and more resistance to aggressive chemicals. Furthermore, metakaolin improves concrete resistance to ASR and sulfate attack.
Sustainability considerations of fly ash, slag cement and metakaolin.Fly ash generated by coal-fired power stations is a global environmental headache, creating groundwater and air pollution from vast landfills and ash dams.
The waste product can be repurposed into.