Damage of magnesium potassium phosphate cement under dry and wet cycles and sulfate attack

•Effects of dry-wet cycles and sulfate attack on MKPC were researched.•Effects of fly ash and quartz sand on the damage of MKPC were tested.•Performance degradation mechanism of MKPC was discussed. Magnesium potassium phosphate cement (MKPC) produced by dead burnt magnesia (MgO) and potassium dihydr...

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Bibliographic Details
Published in:Construction & building materials 2019-06, Vol.210, p.111-117
Main Authors: Li, Yue, Shi, Tongfei, Li, Yaqiang, Bai, Weiliang, Lin, Hui
Format: Article
Language:English
Subjects:
Building materials
Climate change
Concretes
Dry-wet cycle
Durability
Environmental aspects
Magnesium potassium phosphate cement
Mechanical properties
Phosphates
Pore structure
Sulfates
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Summary:•Effects of dry-wet cycles and sulfate attack on MKPC were researched.•Effects of fly ash and quartz sand on the damage of MKPC were tested.•Performance degradation mechanism of MKPC was discussed. Magnesium potassium phosphate cement (MKPC) produced by dead burnt magnesia (MgO) and potassium dihydrogen phosphate (KH2PO4) is a rapid repairing material. In order to repair concrete structures under dry-wet cycles and sulfate attack condition, the degradation of MKPC under the dry-wet cycles in 5 wt% Na2SO4 solution was analyzed by investigating the mass loss and compressive strength in this paper. In addition, the influences of fly ash and quartz sand on the MKPC were also discussed. The degradation mechanism of the MKPC samples and influence mechanism of fly ash and quartz sand were analyzed based on the pore structure, XRD and SEM. The mass and compressive strength of MKPC progressively decrease after dry-wet cycles. The pore structure of MKPC was optimized by fly ash; the sample with fly ash showed improved durability under dry-wet cycles. The sample with quartz sand showed poor durability under dry-wet cycles since the quartz sand led to the initial defect and interfacial transition zone in the MKPC matrix.
ISSN:0950-0618
1879-0526
DOI:10.1016/j.conbuildmat.2019.03.213