Alkali activated fly ash: effect of admixtures on paste rheology

Criado, Manuel; Palomo, A.; Fernández-Jiménez, Ana; Banfill, Phillip Frank Gower

doi:10.1007/s00397-008-0345-5

Cited by 147 publications

(80 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…FTIR results of various alkali activated mortars are shown in Table 3 The similar spectra in Criado works and stated that the formation of solidification product marked with wavelength number reduction in similar bonding in fly ash based alkaliactivated material [5]. Broad peak around 3400 cm -1 indicates the presence of O-H bending vibration.…”

Section: Ftir Resultsmentioning

confidence: 57%

The Effect of Pulp Industrial Waste as Chemical Admixture to Compressive Strength of Fly Ash Based Alkali Activated Materials

2017

View full text Add to dashboard Cite

Abstract. Black liquor is a toxic by-product from industrial pulp manufacture. It contains sodium hydroxide that can be used as precursor activator for alkali activated material, which is an aluminosilicate material that can be prepared from thermal activation of solid material containing alumina and silica as precursor and alkali activator solution. In this work, alkali activated mortar was prepared by mixing fly ash as main precursors, aggregate, followed by addition of activator solution containing sodium hydroxide solution and waterglass, and chemical admixture which is lignin or black liquor. The best compressive strength was 34.40 MPa achieved in addition of 10 wt% of black liquor to alkali activated mortar. X-ray diffraction demonstrated the formation of albite in mortars, indicating that geopolymerization have been successfully formed. FTIR spectra showed the presence of siloxo and sialate peaks which commonly found in geopolymerization.

show abstract

Section: Ftir Resultsmentioning

confidence: 57%

The Effect of Pulp Industrial Waste as Chemical Admixture to Compressive Strength of Fly Ash Based Alkali Activated Materials

2017

View full text Add to dashboard Cite

show abstract

“…This is of significant importance in the case of non-Portland cement pastes, such as alkali activated cement paste, as their workability can be very sensitive to factors such as mix formulation (e.g. type and concentration of activator), reaction kinetics, time-dependent behaviour of fresh paste [20] and mixing procedure [21], and the correlation between flow table and rheological test results for these materials has been shown in the past to be problematic [22]. So, a series of alkali-activated pastes are used here as a test case for the proposed protocols.…”

Section: Introductionmentioning

confidence: 99%

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

2017

View full text Add to dashboard Cite

The mini-slump test is a fast, inexpensive and widely adopted method for evaluating the workability of fresh cementitious pastes. However, this method lacks a standardised procedure for its experimental implementation, which is crucial to guarantee reproducibility and reliability of the test results. This study investigates and proposes a guideline procedure for mini-slump testing, focusing on the influence of key experimental (mixing and testing) parameters on the statistical performance of the results. The importance of preparation of always testing at the same time after mixing, testing each batch once rather than conducting multiple tests on a single batch of material, is highlighted. A set of alkali-activated fly ash-slag pastes, spanning from 1 to 75 Pa yield stresses, were used to validate the test method, by comparison of calculated yield stresses with the results obtained using a conventional vane viscometer. The proposed experimental procedure for mini-slump testing produces highly reproducible results, and the yield stress calculated from mini-slump values correlate very well with those measured by viscometer, in the case of fresh paste of pure shear flow. Mini-slump testing is a reliable method that can be utilised for the assessment of workability of cements.

show abstract

“…Such type of chemical admixtures does not work in Geopolymer system because of high alkaline conditions. [15][16][17][18][19][20] Flyash activated with 85% of 12.5 M NaOH solution and 15% of waterglass with commercial chemical admixtures such as lignosulphonates, melamines(first and second generation products) and polycarboxylates (latestgeneration) were reported. The flow table spread results showedthat the polycarboxylates admixture gave the highest spread, AAFA without admixture came in the second place, melamines admixturecame in the third place, whilst lignosulphates admixturecame in the last place.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the Role of Cetyltrimethylammoniumbromide (CTAB) and Acetylenicglycol (AG) Admixture on Fly Ash Based Geopolymer

Revathi¹,

Jeyalakshmi²,

Rajamane³

et al. 2017

Orient. J. Chem

View full text Add to dashboard Cite

Alkali activation of fly ash with proper mix design and correct formulations can exhibit very good strength and chemical resistance and other potentially valuable characteristics similar or even better than conventional Portland cement. Utilization of fly ash activated system as binder material in construction industry can limit the consumption of virgin materials required for the production of cement as well less energy intensive process in the manufacturing stage leads to lower greenhouse gas emission. Goeopolymeric products with characteristic properties can be achieved on a laboratory scale level by optimizing the process conditions using selected source material with the addition of admixture. On contrary, Usage of variable source material in a large scale preparation, issues like flow ability, control of setting time are always present that need to be studied. This study was conducted on leaching of fly ash by hybrid activator solution namely sodium silicate, sodium hydroxide, for preparing geopolymer matrix wherein geopolymer (GPC) mortar was made with the addition of organic admixture Cetyltrimethylammonium bromide (CTAB), Acetylenic glycol (AG) as flow ability enhancer with dosage ranging from 0-2% by keeping the Liquid/Solid as 0.45.The Compressive strength of the mortar in the order 30 Mpa was achieved with good flow property by the addition acetylenic glycol and the zeta potential value was found to be similar in the order of control specimen (-15.4mv). Analysis of SEM microstructure of the matrix revealed that binding gel of type Na-S-H are found to be more on AEG added matrix than that of CTAB.

show abstract

Alkali activated fly ash: effect of admixtures on paste rheology

Cited by 147 publications

References 31 publications

The Effect of Pulp Industrial Waste as Chemical Admixture to Compressive Strength of Fly Ash Based Alkali Activated Materials

The Effect of Pulp Industrial Waste as Chemical Admixture to Compressive Strength of Fly Ash Based Alkali Activated Materials

Reproducible mini-slump test procedure for measuring the yield stress of cementitious pastes

Evaluation of the Role of Cetyltrimethylammoniumbromide (CTAB) and Acetylenicglycol (AG) Admixture on Fly Ash Based Geopolymer

Contact Info

Product

Resources

About