COLORADO REACTIVE AGGREGATE
addition, low alkali cement replaced the high alkali cement in one set of bars to determine the effect. The resul ts are shown in Table 3. The fly ashes reduced expansion by 57% to 84%. Two of the four fly ashes meet the test criteria of a 75% reduction of expansion. Use of low alkali cement yielded the most dramatic reduction
(PDF) Hybrid alkaline cements. Part I: Fundamentals
These cements form when blends containing low proportions of cement and high proportions (60-70 %) of mineral additions (slag, fly ash or metakaolin) are alkali activated. This article reviews the ...
Shelf life of alkali activated cement: Effects of …
An experimental investigation was conducted in order to evaluate the effects of storage in air and in sealed condition on the properties and performance of alkali …
Efflorescence Formation and Control in Alkali-Activated
Efflorescence formation is an important soundness issue to be considered with alkali-activated cements. In this study, the impact of activator type on the efflorescence formation severity and methods of efflorescence reduction in alkali-activated phosphorus slag cement are investigated. Different alkaline activators including NaOH, KOH and …
Explained: Cement vs. concrete — their differences, and …
Cement plants grind clinker down to an extremely fine powder and mix in a few additives. The final result is cement. "Cement is then brought to sites where it is mixed with water, where it becomes cement paste," explains Professor Franz-Josef Ulm, faculty director of the MIT Concrete Sustainability Hub (CSHub).
A review on alkali-aggregate reactions in alkali-activated …
Alkali-activated binders are attracting more and more attention as they could potentially be substitutes for traditional Portland cement. Alkali-aggregate reaction (AAR) has been intensively studied for Portland cement-based materials, but much less investigated for the alkali-activated binders. Thereby, precautions should still be made …
Fracture evolution of fiber-reinforced backfill based on …
To investigate the fracture evolution of fiber-reinforced backfill, uniaxial compression tests were conducted on different fiber types of reinforced backfills, and the fracture process of fiber-reinforced backfill was monitored using an acoustic emission (AE) system. The fracture evolution characteristics of the fiber-reinforced backfill were …
Application of electric arc furnace slag as an alternative …
This study dealt with the synthesis and characterization of alkali activated slag cement (AAS) based on EAFS with addition of 1-7% of Zn-rich EAFD dopant. Effects of slag replacement with dust on ...
Alkálifém
Egyes beton-adalékanyagok és az alkálifém-oxid dús cementek hidratációs termékében levő alkálifém-hidroxidok beépülési, vagy csere-bomlásának a megnevezése.A reakció a …
242-22: Alkali-Activited Cements—Report
CHAPTER 6—ALKALI-ACTIVATED CEMENT CHALLENGES AND OPPORTUNITIES, p. 8 6.1—Drying and autogenous shrinkage, p. 8 6.2—Durability, p. 9 6.3—Environmental impact, p. 9 CHAPTER 7—ALKALI-ACTIVATED CEMENT APPLICATIONS, p. 10 Authored documents, p. 11 CHAPTER 1—INTRODUCTION AND SCOPE 1.1—Introduction …
Effect of alkali content of cement on properties of high …
When alkali content of cement increases, or total alkali content of concrete increases, the potential for ASR in concrete increases [11], [12], [13]. A study on the ASR induced expansion of concrete with alkali content of cement varying from 0.9% to 1.25% Na 2 O eq was conducted by Rogers et al. [12].
Reactions of alkalis, chlorine and sulfur during clinker production
Abstract. It is well known that alkalis, chlorine and sulfur decrease kiln efficiency in the cement industry. At high temperatures thermally unstable compounds like alkali chlorides, alkali ...
Compressive strength, pore structure and chloride
For pore structure measurement, samples with various silicate moduli, alkali dosages or fly ash contents with combinations of two fixed factors of three (Ms = 1.0, FA% = 20%, Na 2 O = 4%) were prepared. The AASF mortars with slag (AAS), silicate modulus of 0 and different alkali dosages (2, 4, 6 and 8%) were prepared for studies on …
Determination of Potassium, Sodium, and Total Alkalies in …
A simple flow injection with flame photometric detection has been developed for determination of sodium, potassium, and total alkalies in portland cement, fly ash, admixtures, and water of concrete. A liquid sample or a digest of solid sample was injected into a water carrier stream which flowed to a flame photometer. A change in emission …
Characterization of Blast Furnace Slag for Preparing Activated Alkali …
Blast furnace slag (BFS) activated alkali cements are an alternative to the use of Portland cement. The objective of this work was to characterize a BFS for potential application as an activated alkali cement. Characterizations were performed using SEM, particle size, physical parameter analysis, chemical composition, XRD, FTIR, and ATD.
Alkali-Aggregate Reaction
This alkali-aggregate reaction has two forms: alkali-silica reaction (ASR) and alkali-carbonate reaction (ACR). Alkali-silica reaction (ASR) is of more concern because aggregates containing reactive silica materials are more common. In ASR, aggregates containing certain forms of silica will react with alkali hydroxide in concrete to form a gel ...
Frontiers | Efflorescence of Alkali-Activated …
Even with the rapid development of the alkali-activated cement (AAC) technology in the past few years, some phenomena still needs to be better understood, that may alter the durability of the material. In many …
Materials | Free Full-Text | A Review on Alkali-Silica Reaction …
Alkali-silica reaction (ASR) is one of the major degradation causes of concrete. This highly deleterious reaction has aroused the attention of researchers, in order to develop methodologies for its prevention and mitigation, but despite the efforts made, there is still no efficient cure to control its expansive consequences. The incorporation of …
The pore solution of blended cements: a review
This paper is the work of working group 3 of the RILEM Technical Committee on Hydration and Microstructure of Concrete with SCM (TC 238-SCM). The pore solution is an essential but often overlooked part of hydrated cements. The composition of the cement pore solution reflects the ongoing hydration processes and determines which solid …
Structure and Properties of Alkaline Cement and Concrete …
The chapter covers the results of influence of changes in proportions between Portland cement and slag content, along with different quantities of alkali components in the cement systems on their heat of hydration and the effect of this during their hardening on character of internal stresses development and crack opening in …
Na k o.
of alkalies in cement and concrete, to indicate the effects of.àlkalies in cement reactions and in various phenomena which occur in freshly-mixed and hardened cement paste …
Buildings | Free Full-Text | Alkali-Activated Binder Based on …
The development of low-carbon alkali-activated binders based on production waste is one of the most sought-after areas of development of building materials science. The article examines the results of studies of the structures of cupola dust and the assessment of its ability to hydrate when exposed to alkaline activation. Technological …
Volume 3, Issue 1
The alkali content of the concrete can be calculated by multiplying the portland cement content of the concrete by the alkali content of the cement. For example, a concrete produced with 650 lb/yd 3 of portland cement having an equivalent alkali content of 0.52% Na 2 O eq (by mass) has an alkali content of 650 x 0.52/100 = 3.38 …
Comparison of alkali–silica reactions in alkali-activated …
2.1 Raw materials. A low alkali Portland cement (PC) and a ground blast furnace slag (SL) powder were used. Their chemical composition is presented in Table 1.The activator used to produce alkali-activated slag (AAS) was water–glass with the silicate modulus (Ms = SiO 2 /Na 2 O by mass) of 1.5. It was prepared by adding certain amount …
Environmental Impact and Sustainability of …
This investigation presents a critical analysis of calcium aluminate cements (CAC), specifically associated with sustainability and environmental impact, and the potential of these cements to help solve …
Effect of alkali content of cement on properties of high …
A study on the ASR induced expansion of concrete with alkali content of cement varying from 0.9% to 1.25% Na 2 O eq was conducted by Rogers et al. [12]. The base Portland cement had alkali content of 0.9% Na 2 O eq, and higher alkali content was achieved by dissolving corresponding quantity of sodium hydroxide (NaOH) into mixing …
ASTM C33
Designation Design ation:: C33/C33 C33/C33M M – 08. Standard Specification for. Concrete Aggregates 1 This standard is issued under the fixed designation C33/C33M; the number immediately following the designation indicates the year of original origin al adoption or, in the case of revis revision, ion, the year of last revision. …
Combining ESP and baghouse technology (Conference)
Lawrence Cement Company, a plant in Beauport Canada, has been in operation since 1955. Their two wet process kilns have utilized electrostatic precipitator (ESP) filters since inception. Since 1965, this company has strived to reduce energy consumption by using alternative waste fuel. This, combined with the increased demand …
Long-term alkali–silica mitigation of high-alkali concrete …
For the 1.10% and 1.25% alkali cements, the CSA criteria would require at least 40% fly ash and 60% slag cement to mitigate deleterious expansion for the Spratt …
Topical chemical burns: Initial assessment and management
Cement burns — Wet cement is a poorly recognized and under-reported cause of alkali burns. A cement mixture has an initial pH of 10 to 12 that may rise as high as 14 as hydrolysis occurs and the cement sets. Cement burn injuries occur most often on the lower legs and knees . Presenting symptoms generally occur several hours after …