The Strength and Drying Shrinkage Properties of Alkali-Activated Slag Mortars as the Particle Size of Blended Fine Aggregate

2015 ◽  
Vol 27 (3) ◽  
pp. 273-281
Author(s):  
Tae Wan Kim
Keyword(s):  
Particle Size ◽  
Drying Shrinkage ◽  
Fine Aggregate ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

scholarly journals Pottery Sand as Fine Aggregate for Preparing Alkali-Activated Slag Mortar

2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Zhenzhen Jiao ◽  
Ying Wang ◽  
Wenzhong Zheng ◽  
Wenxuan Huang
Keyword(s):  
Compressive Strength ◽  
Mechanical Performance ◽  
Setting Time ◽  
Drying Shrinkage ◽  
Sodium Oxide ◽  
Oxide Content ◽  
Fine Aggregate ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

Alkali-activated slag (AAS) mortars were prepared using pottery sand as a fine aggregate in a ratio of 1 : 1.75 using a blend of sodium silicate and NaOH as an alkaline activator at room temperature. The effects of sodium oxide content and silicate moduli on the setting time, fluidity, consistency, compressive strength, and drying shrinkage of different AAS mortars were determined. These results revealed that sodium oxide content and silicate modulus had little effect on the setting time and workability of the mortar; however, they did have a significant effect on their mechanical performance and drying shrinkage levels. All the AAS mortars exhibited faster setting times, better workability, and higher early and late compressive strength compared to traditional mortars. Optimum compressive strength was achieved at 93 and 123 MPa after 1 d and 28 d, respectively, using a silicate modulus of 1.2 and Na2O content of 8%. The microstructures of mortars were characterized using scanning electron microscopy with energy dispersive spectrometric (SEM/EDS) and mercury intrusion porosimetry (MIP). These results reveal that AAS mortars containing pottery sand as a fine aggregate may represent a promising building material with improved properties for use in the construction industry.

scholarly journals Mitigating the Drying Shrinkage and Autogenous Shrinkage of Alkali-Activated Slag by NaAlO2

Materials ◽  
2020 ◽  
Vol 13 (16) ◽  
pp. 3499
Author(s):  
Bin Chen ◽  
Jun Wang ◽  
Jinyou Zhao
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Nitrogen Adsorption ◽  
Partial Substitution ◽  
Hydration Reaction ◽  
X Ray Diffraction ◽  
Na2o Content ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

The shrinkage of alkali-activated slag (AAS) is obviously higher than ordinary Portland cement, which limited its application in engineering. In this study, the effects of NaAlO2 in mitigating drying shrinkage and autogenous shrinkage of AAS were studied. To further understand the shrinkage mechanism, the hydration products and microstructures were studied by X-ray diffraction, scanning electron microscopy and nitrogen adsorption approaches. As the partial substitution rate of NaAlO2 for Na2SiO3 increased, the drying shrinkage and autogenous shrinkage reduced significantly. The addition of NaAlO2 could slow down the rate of hydration reaction and reduce the porosity, change the pore diameter and the composition of generated paste and cause more hydrotalcite and tetranatrolite generated—which contributed to reduced shrinkage. Additionally, raising the Na2O content rate caused obvious differences in drying shrinkage and autogenous shrinkage. As the Na2O content elevated, the drying shrinkage decreased and autogenous shrinkage increased. A high Na2O content would cause complete hydration reactions and provoke high autogenous shrinkage. However, incomplete hydration reactions left more water in the paste, and the evaporated water dramatically influenced drying shrinkage. The results indicate that addition of NaAlO2 could greatly mitigate the drying shrinkage and autogenous shrinkage of AAS.

scholarly journals Understanding the drying shrinkage performance of alkali-activated slag mortars

2017 ◽  
Vol 76 ◽  
pp. 13-24 ◽  
Author(s):  
Hailong Ye ◽  
Christopher Cartwright ◽  
Farshad Rajabipour ◽  
Aleksandra Radlińska
Keyword(s):  
Drying Shrinkage ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Alkali Activated

Shrinkage Behavior of Alkali-Activated Slag Cement Pastes

2018 ◽  
Vol 761 ◽  
pp. 45-48 ◽  
Author(s):  
Vladyslav Omelchuk ◽  
Guang Ye ◽  
Rayisa Runova ◽  
Igor I. Rudenko
Keyword(s):  
Autogenous Shrinkage ◽  
Drying Shrinkage ◽  
Chemical Shrinkage ◽  
Slag Cement ◽  
Cement Pastes ◽  
Alkali Activated Slag ◽  
Activated Slag ◽  
Mineral Additives ◽  
Alkali Activated ◽  
Shrinkage Behavior

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.

Basaltic Crushed Rock Stabilized with Cementitious Additives: Compressive Strength and Stiffness, Drying Shrinkage, and Capillary Flow Characteristics

2003 ◽  
Vol 1819 (1) ◽  
pp. 18-26 ◽  
Author(s):  
Srijib Chakrabarti ◽  
Jayantha Kodikara
Keyword(s):  
Capillary Rise ◽  
Blended Cement ◽  
Drying Shrinkage ◽  
Basaltic Rock ◽  
General Purpose ◽  
Binder Content ◽  
Alkali Activated Slag ◽  
Basaltic Rocks ◽  
Activated Slag ◽  
Alkali Activated

Research was undertaken to increase knowledge of the properties of local stabilized pavement materials to facilitate their wider use in road construction and rehabilitation. Laboratory tests involved testing for the unconfined compressive strength (UCS), shrinkage, and capillary behavior of crushed basaltic rocks stabilized with two conventional cementitious binders—general purpose cement and lime—and two cementitious binders comprising industrial waste products—blended cement and alkali-activated slag. The alkali-activated slag and blended cement significantly increased UCS of untreated material and performed as well as or better than such traditional binders as general purpose cement. Overall, lime performed poorly as a stabilizer of crushed basaltic rocks, primarily because the fine content containing clay minerals was not significant in the crushed basaltic rock composition. UCS of stabilized materials increased significantly as binder content increased; UCS could be described as a function of binder quantity. Ultimate shrinkage increased with binder content for general purpose cement and alkali-activated slag, but for blended cement, behavior was different. The rate of drying shrinkage was relatively high at the early stage of shrinkage. Generally, alkali-activated slag produced less shrinkage compared with general purpose and blended cements. Capillary rise and water absorption were also measured. Test results indicated that the rate of capillary rise and amount of water absorbed by the material matrix decreased with the increase of binder content. The research indicated that the use of binders with industrial by-products could be a viable option in stabilization of crushed basaltic rock materials.

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