Investigation of effects of reactive MgO on autogenous and drying shrinkage of near-neutral salt activated slag cement

Nowadays, alkali-activated cements (AACs) are the most promising alternatives to ordinary portland cement (OPC). Such cements characterized by better strength and corrosion resistance that determine improved durability of materials based on them. However, the shrinkage of AAC systems is noticeably higher compared with OPC. The purpose of this work was to study the shrinkage behavior of alkali-activated slag cement (AASC) pastes. To improve early age performance of AASCs – OPC and Ca(OH)2, as mineral additives, were added to the designed cement mixtures. The properties, like, flexural and compressive strength of cement mortars, chemical shrinkage, autogenous shrinkage and drying shrinkage of cement pastes were studied. The results showed that the chemical shrinkage, autogenous shrinkage and drying shrinkage at 28 days were between 0.064 – 0.074 ml/g, 4.5 – 7.9 mm/m and 3.3 – 4.9 mm/m, respectively. The relationship between the nature of alkaline components, the type of mineral additives and the shrinkage behavior of cements were discussed.

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Influence of hydrated lime on mechanical and shrinkage properties of alkali-activated slag cement

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123201 ◽

2021 ◽

Vol 289 ◽

pp. 123201

Author(s):

Juan He ◽

Wenbin Bai ◽

Weihao Zheng ◽

Junhong He ◽

Guochen Sang

Keyword(s):

Hydrated Lime ◽

Slag Cement ◽

Alkali Activated Slag ◽

Activated Slag ◽

Alkali Activated

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Chemical and physical effects of high-volume limestone powder on sodium silicate-activated slag cement (AASC)

Construction and Building Materials ◽

10.1016/j.conbuildmat.2021.123257 ◽

2021 ◽

Vol 292 ◽

pp. 123257

Author(s):

Xiaohong Zhu ◽

Xiaojuan Kang ◽

Jiaxin Deng ◽

Kai Yang ◽

Shouheng Jiang ◽

...

Keyword(s):

Sodium Silicate ◽

High Volume ◽

Limestone Powder ◽

Slag Cement ◽

Physical Effects ◽

Activated Slag

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Effect of CaSO4 Incorporation on Pore Structure and Drying Shrinkage of Alkali-Activated Binders

Materials ◽

10.3390/ma12101673 ◽

2019 ◽

Vol 12 (10) ◽

pp. 1673 ◽

Cited By ~ 3

Author(s):

Hyeongmin Son ◽

Sol Moi Park ◽

Joon Ho Seo ◽

Haeng Ki Lee

Keyword(s):

Fly Ash ◽

Pore Structure ◽

Drying Shrinkage ◽

Phase Changes ◽

X Ray Diffraction ◽

Activated Slag ◽

Capillary Tension ◽

Alkali Activated Binders ◽

Internal Pore Structure ◽

Alkali Activated

This present study investigates the effects of CaSO4 incorporation on the pore structure and drying shrinkage of alkali-activated slag and fly ash. The slag and fly ash were activated at a 5:5 ratio by weighing with a sodium silicate. Thereafter, 0%, 5%, 10%, and 15% of CaSO4 were incorporated to investigate the changes in phase formation and internal pore structure. X-Ray Diffraction (XRD), thermogravimetry (TG)/derivative thermogravimetry (DTG), mercury intrusion porosimetry (MIP), nuclear magnetic resonance (NMR), and drying shrinkage tests were carried out to find the correlation between the pore structure and drying shrinkage of the specimens. The results showed that CaSO4 incorporation increased the formation of thenardite, and these phase changes affected the pore structure of the activated fly ash and slag. The increase in the CaSO4 content increased the pore distribution in the mesopore. As a result, the capillary tension and drying shrinkage decreased.

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