Location
ICDCS 2018 Leeds
Event Website
https://engineering.leeds.ac.uk/info/201479/conferences/270/sixth_international_conference_on_durability_of_concrete_structures_icdcs2018/4
Keywords
Hardened cement paste, Mesoscopic model, Drying shrinkage, Slit-like pore, C-S-H, Shrinkage reducing admixture
Abstract
Concrete shrinks when it is subjected to drying, whenever its surfaces are exposed to air of a low relative humidity. In such a situation, cracking is to be expected, since there are various kinds of restraint that prevent concrete from contracting freely. Unless the ambient relative humidity is kept at close to 100%, such shrinkage cracking presents a critical problem in concrete construction, in particular for thin, flat structures such as walls and slabs in buildings, highway pavements, and bridge decks. This paper review the state of art of theory drying shrinkage from focus on the fact that microstructure in cement paste matrix consists of slit like pores as well as cylindrical shape pores. According to this fact, a new mesoscopic model of drying shrinkage is proposed. Our model can reproduce the experimental hysteresis loop of drying shrinkage for hardened cement paste, and reveals that drying shrinkage is closely related to the interaction potential between C-S-H nano-scale particles in cement systems. Meanwhile controlling cracking is essentially accomplished by reducing drying shrinkage. This paper also describes the efficiency of shrinkage reducing admixtures (SRAs) in controlling the restrained shrinkage cracking of concrete based on the mechanism of drying shrinkage.
Included in
Mescopic model of drying shrinkage and its application into control of shrinkage cracking
ICDCS 2018 Leeds
Concrete shrinks when it is subjected to drying, whenever its surfaces are exposed to air of a low relative humidity. In such a situation, cracking is to be expected, since there are various kinds of restraint that prevent concrete from contracting freely. Unless the ambient relative humidity is kept at close to 100%, such shrinkage cracking presents a critical problem in concrete construction, in particular for thin, flat structures such as walls and slabs in buildings, highway pavements, and bridge decks. This paper review the state of art of theory drying shrinkage from focus on the fact that microstructure in cement paste matrix consists of slit like pores as well as cylindrical shape pores. According to this fact, a new mesoscopic model of drying shrinkage is proposed. Our model can reproduce the experimental hysteresis loop of drying shrinkage for hardened cement paste, and reveals that drying shrinkage is closely related to the interaction potential between C-S-H nano-scale particles in cement systems. Meanwhile controlling cracking is essentially accomplished by reducing drying shrinkage. This paper also describes the efficiency of shrinkage reducing admixtures (SRAs) in controlling the restrained shrinkage cracking of concrete based on the mechanism of drying shrinkage.
https://docs.lib.purdue.edu/icdcs/2018/keynote/7
