Calcium Aluminate Cements

Mangabhai, Raman

doi:10.4324/9780203473245

Cited by 33 publications

(17 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The two former hydrates are termed as metastable, as in time they transform to C 3 AH 6 which coexists with AH 3 , and stratlingite phases at ''mature'' times [19]. Since this nature of phase transformations involves the expulsion of water from the solids, the resulting accumulation of water in the microstructure results in an increase in porosity, and a detrimental reduction in the mechanical properties [20][21][22]. This process is termed as ''conversion'' [16].…”

Section: Introductionmentioning

confidence: 99%

The influence of slightly and highly soluble carbonate salts on phase relations in hydrated calcium aluminate cements

et al. 2016

View full text Add to dashboard Cite

The addition of slightly (CaCO 3) and highly soluble (Na 2 CO 3) carbonate salts is expected to favor the formation of carboaluminate phases in hydrated calcium aluminate cements (CACs). A multi-method approach including X-ray diffraction, thermogravimetric analysis, and thermodynamic calculations is applied to highlight that the ''conversion phenomena'' in CACs cannot be mitigated by the formation of carboaluminate phases (monocarboaluminate: Mc and hemicarboaluminate: Hc) which are anticipated to form following the addition of carbonate salts. Here, carboaluminate phase formation is shown to depend on three factors: (1) water availability, (2) carbonate content of the salts, and their ability to mobilize CO 3 2species in solution, and (3) lime content associated with the carbonate salt. The latter two factors are linked to the composition and solubility of the carbonate agent. It is concluded that limestone (CaCO 3), despite being a source of calcium and carbonate species, contributes only slightly to carboaluminate phase formation due to its low solubility and slow dissolution rate. Soluble carbonate salts (Na 2 CO 3) fail to boost carboaluminate phase formation as the availability of Ca 2? ions and water are limiting. Detailed thermodynamic calculations are used to elucidate conditions that affect the formation of carboaluminate phases.

show abstract

Section: Introductionmentioning

confidence: 99%

The influence of slightly and highly soluble carbonate salts on phase relations in hydrated calcium aluminate cements

et al. 2016

View full text Add to dashboard Cite

show abstract

“…In early stages of CAC hydration, unequal solubility of Ca 2+ and aluminate ions leads to roughening of the surface and enrichment of Al 2 O 3 . This incongruent solubility of ions increases the surface area and charge density of the hydrating particles, whereby double hydroxides of cationic [Ca 2 Al(OH) 6 ] + are formed as the hydrating product 28 29 . In agreement with the results of Mangabhai 29 , we have also observed high rate of surface development in CAC suspensions ( Supplementary Table S2 ) that is accompanied by the introduction of high positive potentials to the surface of particles (+30 mV).…”

Section: Resultsmentioning

confidence: 99%

“…This incongruent solubility of ions increases the surface area and charge density of the hydrating particles, whereby double hydroxides of cationic [Ca 2 Al(OH) 6 ] + are formed as the hydrating product 28 29 . In agreement with the results of Mangabhai 29 , we have also observed high rate of surface development in CAC suspensions ( Supplementary Table S2 ) that is accompanied by the introduction of high positive potentials to the surface of particles (+30 mV). Therefore, high rate of surface development, surface charge density of hydrating particles, and affinity of adsorption result in depletion of anionic PCEs (AMPS-PCEs) from CAC suspensions.…”

Section: Resultsmentioning

confidence: 99%

Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

Akhlaghi

Menceloǵlu

Akbulut

2017

Sci Rep

View full text Add to dashboard Cite

Calcium aluminate cement (CAC) suffers from loss of workability in less than an hour (~15 minutes) after first touch of water. Current superplasticizers that are utilized to modify the viscosity of cement admixtures are designed to target ordinary Portland cement (OPC). The high affinity between these superplasticizers and cement particles were found to be detrimental in CAC systems. Utilization of a monomer that, instead, facilitates gradual adsorption of a superplasticizer provides workability retention. For the first time in literature, we report a superplasticizer that caters to the properties of CAC such as high rate of surface development and surface charge. While neat CAC was almost unworkable after 1 hour, with the addition of only 0.4% of the optimized superplasticizer, 90% fluidity retention was achieved.

show abstract

“…Moreover, CA-hydrations in the CAC matrix may accelerate adorption of Ca(OH) 2 , of which precipitation is removed, as being more resistive to aggressive chemical environments. For example, the absence of Ca(OH) 2 hydrations may minimize the risk of sulfate attack, which must accompany Ca(OH) 2 in the cement matrix to react with sulfate ions to produce expansive ettringite [ 17 , 18 ]. The benefit of CAC mixture may be associated with a rapid setting time of fresh concrete, of which value can be reduced to 3.0 h or below then to develop a very early strength of concrete.…”

Section: Discussionmentioning

confidence: 99%

Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment

Ann

Cho

2014

Materials

View full text Add to dashboard Cite

The present study concerns a development of calcium aluminate cement (CAC) concrete to enhance the durability against an externally chemically aggressive environment, in particular, chloride-induced corrosion. To evaluate the inhibition effect and concrete properties, CAC was partially mixed with ordinary Portland cement (OPC), ranging from 5% to 15%, as a binder. As a result, it was found that an increase in the CAC in binder resulted in a dramatic decrease in the setting time of fresh concrete. However, the compressive strength was lower, ranging about 20 MPa, while OPC indicated about 30–35 MPa at an equivalent age. When it comes to chloride transport, there was only marginal variation in the diffusivity of chloride ions. The corrosion resistance of CAC mixture was significantly enhanced: its chloride threshold level for corrosion initiation exceeded 3.0% by weight of binder, whilst OPC and CAC concrete indicated about 0.5%–1.0%.

show abstract

Calcium Aluminate Cements

Cited by 33 publications

References 0 publications

The influence of slightly and highly soluble carbonate salts on phase relations in hydrated calcium aluminate cements

The influence of slightly and highly soluble carbonate salts on phase relations in hydrated calcium aluminate cements

Poly(carboxylate ether)-based superplasticizer achieves workability retention in calcium aluminate cement

Corrosion Resistance of Calcium Aluminate Cement Concrete Exposed to a Chloride Environment

Contact Info

Product

Resources

About