Effect of limestone on engineering properties of alkali-activated concrete: A review

Chan, Choi Lin; Zhang, Mingzhong

doi:10.1016/j.conbuildmat.2022.129709

Cited by 23 publications

(12 citation statements)

References 126 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The μ-limestone addition in the slag acts as a nucleating agent and a C-S-H gel precursor [ 75 ], besides a filler effect [ 48 ].…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Microstructural and Mechanical Characteristics of Alkali-Activated Binders Composed of Milled Fly Ash and Granulated Blast Furnace Slag with µ-Limestone Addition

Vázquez-Rodríguez,

Elizondo,

Montes-González

et al. 2023

Materials

View full text Add to dashboard Cite

Concrete is the most used construction material, needing large quantities of Portland cement. Unfortunately, Ordinary Portland Cement production is one of the main generators of CO2, which pollutes the atmosphere. Today, geopolymers are an emerging building material generated by the chemical activity of inorganic molecules without the Portland Cement addition. The most common alternative cementitious agents used in the cement industry are blast-furnace slag and fly ash. In the present work, the effect of 5 wt.% µ-limestone in mixtures of granulated blast-furnace slag and fly ash activated with sodium hydroxide (NaOH) at different concentrations was studied to evaluate the physical properties in the fresh and hardened states. The effect of µ-limestone was explored through XRD, SEM-EDS, atomic absorption, etc. The addition of µ-limestone increased the compressive strength reported values from 20 to 45 MPa at 28 days. It was found by atomic absorption that the CaCO3 of the μ-limestone dissolved in NaOH, precipitating Ca(OH)2 as the reaction product. SEM-EDS analysis showed a chemical interaction between C-A-S-H- and N-A-S-H-type gels with Ca(OH)2, forming (N, C)A-S-H- and C-(N)-A-S-H-type gels, improving mechanical performance and microstructural properties. The addition of μ-limestone appeared like a promising and cheap alternative for enhancing the properties of low-molarity alkaline cement since it helped exceed the 20 MPa strength recommended by current regulations for conventional cement.

show abstract

“…The μ-limestone addition in the slag acts as a nucleating agent and a C-S-H gel precursor [ 75 ], besides a filler effect [ 48 ].…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, many studies have demonstrated improvements of the properties of Portland cement by limestone (CaCO 3 ) addition. It has been reported that limestone powders homogenize and broadly distribute clinker particle size when limestone particle sizes below 8 μm are used in a range of 10% to 40% [ 48 ].…”

Section: Introductionmentioning

confidence: 99%

Microstructural and Mechanical Characteristics of Alkali-Activated Binders Composed of Milled Fly Ash and Granulated Blast Furnace Slag with µ-Limestone Addition

Vázquez-Rodríguez,

Elizondo,

Montes-González

et al. 2023

Materials

View full text Add to dashboard Cite

show abstract

“…Moreover, at the same temperature, the CaSO 4 C CO 2 system exhibits a greater rate of CaSO 4 decomposition than the CaSO 4 -C system. This might be as a result of the fact that 1 mol coal combines with CO 2 to produce 2 mol carbon monoxide, which then takes part in the reaction with CaSO 4 to make CaO, as stated in Eqn (4) and (5).…”

Section: Influence Of Temperaturementioning

confidence: 99%

“…According to statistics, the amount of CO 2 emitted annually from the calcination of limestone in China is approximately 10% of the global total CO 2 emissions, making it the third‐largest source of CO 2 emissions in China. Among them, CO 2 emissions from the calcination of industrial limestone account for about 70% of the total emissions 5 . As a result, creating low‐CO 2 ‐emission manufacturing techniques for lime has emerged as a significant problem in the realm of environmental protection in order to meet carbon neutrality objectives.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Wang

2023

J of Chemical Tech & Biotech

View full text Add to dashboard Cite

BACKGROUND: Recent studies show that CaO is being produced from CaSO 4 by CO reduction using fixed-bed reactors. However, the product yield is low and the reaction time is long. Furthermore, the high cost of CO hinders its application in industrial processes. Therefore, a new process is proposed for preparing CaO by CaSO 4 decomposition using lignite under CO 2 . The influence of various process conditions on the production of CaO by CaSO 4 decomposition is investigated by combining kinetic and FactSage simulations. Finally, a typical industrial gypsumphosphogypsum (PG)is used for experimental verification.RESULTS: The study found that adding CO 2 during the coal reduction of CaSO 4 increases the CaO yield. The ideal conditions are 1.75 C/Ca molar ratio, 7.5% CO 2 concentration at 1100 °C with the maximum CaSO 4 decomposition rate and CaO yield of 99.63% and 99.28%, respectively. CaO generation is carried out using a two-step process. Initially, CaSO 4 is reduced to become CaS and CaO, and CaS interacts with CaSO 4 to produce CaO. Secondly, the reaction between CaS and CO 2 produces CaO. The nucleation and growth model with g(⊍) = −ln(1 − ⊍) is applicable to both processes. The experimental use of PG confirms the above conclusions, but SiO 2 in PG reacts with CaO to produce Ca 2 SiO 4 and affect the CaO yield.CONCLUSION: The addition of CO 2 promotes the conversion process of CaSO 4 to CaO. Increasing the temperature, C/Ca molar ratio and CO 2 concentration favor the decomposition of CaSO 4 into CaO. This study offers advice for using CaSO 4 products like PG as resources.

show abstract

Development of sustainable slag-based alkali-activated concrete incorporating fly ash at ambient curing conditions

Pradhan,

Mishra,

Biswal

et al. 2024

Energ. Ecol. Environ.

View full text Add to dashboard Cite

Effect of limestone on engineering properties of alkali-activated concrete: A review

Cited by 23 publications

References 126 publications

Microstructural and Mechanical Characteristics of Alkali-Activated Binders Composed of Milled Fly Ash and Granulated Blast Furnace Slag with µ-Limestone Addition

Microstructural and Mechanical Characteristics of Alkali-Activated Binders Composed of Milled Fly Ash and Granulated Blast Furnace Slag with µ-Limestone Addition

Experimental study on preparation of calcium oxide by coal reduction of calcium sulfate in carbon dioxide atmosphere

Development of sustainable slag-based alkali-activated concrete incorporating fly ash at ambient curing conditions

Contact Info

Product

Resources

About