Effect of microfibers or SRA on the shrinkage and mechanical properties of alkali activated slag/fly ash-based mortars incorporating recycled fine aggregate

Abolfathi, Mehrnosh; Ömür, Tarık; Kabay, Nihat

doi:10.1016/j.conbuildmat.2023.130883

Cited by 13 publications

(4 citation statements)

References 57 publications

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“…Many scholars have done a lot of research on the effect of admixtures on the shrinkage performance of concrete, but different researchers have different conclusions. Abolfathi Mehrnosh [8]added 1.5 % and 3 % shrinkage reducing agent ( SRA ) to cement-based materials. The results showed that compared with the standard group, the volume deformation of cement-based materials decreased by 28 % and 53 %, respectively.…”

Section: Research Status At Home and Abroad On The Effect Of Admixtur...mentioning

confidence: 99%

Review of Research on Volume Shrinkage Regulation Mechanism of Ultra-high Performance Concrete

Yan

2024

AJST

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Ultra-high performance concrete (UHPC) is a cement-based composite building material with excellent durability and mechanical properties, but its autogenous shrinkage and drying shrinkage phenomenon have become a common problem in practical engineering. In order to solve this practical problem, new mineral admixtures and admixtures are usually added to UHPC, and the shrinkage of UHPC is effectively improved.

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Section: Research Status At Home and Abroad On The Effect Of Admixtur...mentioning

confidence: 99%

Review of Research on Volume Shrinkage Regulation Mechanism of Ultra-high Performance Concrete

Yan

2024

AJST

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“…Among these, shrinkage reducing agents (SRAs) and expansive additives (EAs) are commonly used as a material approach. In the study of Abolfathi et al [19], the polypropylene (PP), steel fiber (SF), and hexylene glycol-based SRA were used for mitigating the shrinkage of alkali activated slag and fly ash (AASF) mortars incorporating recycled fine aggregate (RFA), and its characteristics were analyzed. As a result, although the initial compressive strength of AASF mortar incorporating SRA was reduced, a similar level of strength to the reference specimen was obtained at 28 days; in addition, the free and restrained shrinkage were mitigated compared to the specimens incorporating PP and SF.…”

Section: Introductionmentioning

confidence: 99%

Early-Age Shrinkage Stress of Alkali-Activated Cement-Free Mortar Using Shrinkage Reducing Agent and Expansive Additive

Yoon,

Oh,

Kim

et al. 2024

Preprint

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Cement-free concrete has superior physical performance, such as strength and durability, compared to OPC concrete, however, it has the disadvantage of large shrinkage. Large shrinkage can cause cracks due to shrinkage stress in the long term. In this study, a shrinkage reducing agent (SRA) was used to reduce the shrinkage of cement-free mortar; its content was increased from 0.0 to 1.5 %. For an SRA content of 1.0 %, a calcium sulfoaluminate (CSA) expansive additive (EA) (2.5, 5.0, and 7.5%) was added. To calculate the shrinkage stress of cement-free mortar using the SRA and EA, the compressive strength, elastic modulus, and total and autogenous shrinkage were measured. The unit shrinkage stress of cement-free mortar was obtained by multiplying the elastic modulus by the length change and accumulated to obtain the shrinkage stress acting on the mortar according to the age. The shrinkage stress of cement-free mortar showed different tendencies as the age increased. At early ages, the shrinkage rate of the mortar occupied a large proportion of the shrinkage stress. In the long term, the shrinkage stress was significantly affected by the elastic modulus. As a result, SRA was found to be effective in reducing the shrinkage stress by decreasing both the elastic modulus and shrinkage. However, EA increased the shrinkage stress over the long term due to an increase in elastic modulus even though it compensated for early-ages shrinkage.

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“…The widely recognized mechanism of DS is that when the water gradually evaporates, surface tension is generated when the menisci are formed in the gel pores and capillary pores, thereby causing an equal compressive stress in the skeleton and causing volume shrinkage 14,15 . Current research primarily focuses on reducing the DS of AAMs by incorporating bers [16][17][18] , chemical admixtures 4,19 , and mineral admixtures 20,21 , as well as changing the curing system [22][23][24] . Changing the curing system, while effectively reducing shrinkage, may also lead to a decrease in mechanical properties and issues of unstable internal curing humidity 24 .…”

Section: Introductionmentioning

confidence: 99%

Effect of borax-modified activator on mechanical properties and drying shrinkage of alkali-activated slag/metakaolin mortar

Chen,

Qin,

Chen

et al. 2024

Preprint

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Alkali-activated materials (AAMs) possess several advantages, such as high strengths and low carbon emissions. However, their application is hindered due to their significant shrinkage. This study explored the effect of borax-modified sodium silicate activator and metakaolin (MK) on the mechanical properties and drying shrinkage (DS) of alkali-activated slag (AAS) and AAS/MK (AASM) mortars. X-ray diffraction, scanning electron microscopy, and Fourier-transform infrared spectroscopy were used to characterize the hydration products. The results show that the DS reduction of the AAS mortar is related to decreased Na2O content, a reduction in the proportion of mesopores, and the formation of moisture-retaining borate compounds. The DS reduction of the AASM mortar is attributed to the ultra-fine differential effect induced by MK, reducing the connected pores. The modified activator combined with MK increased the chemically bound water content in the matrix. Additionally, the B-O bond and highly active MK improved compactness of the AASM mortar.

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Effect of microfibers or SRA on the shrinkage and mechanical properties of alkali activated slag/fly ash-based mortars incorporating recycled fine aggregate

Cited by 13 publications

References 57 publications

Review of Research on Volume Shrinkage Regulation Mechanism of Ultra-high Performance Concrete

Review of Research on Volume Shrinkage Regulation Mechanism of Ultra-high Performance Concrete

Early-Age Shrinkage Stress of Alkali-Activated Cement-Free Mortar Using Shrinkage Reducing Agent and Expansive Additive

Effect of borax-modified activator on mechanical properties and drying shrinkage of alkali-activated slag/metakaolin mortar

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