Tests on Magnesium Phosphate Composite Mortar Mixtures with Different Molar Ratios of MgO-to-KH2PO4

MgO-KH2PO4 몰비 변화에 따른 마그네시아-인산염 모르타르의 배합실험

  • Yoon, Hyun-Sub (Department of Architectural Engineering, Kyonggi University Graduate School) ;
  • Lee, Kyung-Ho (Department of Architectural Engineering, Kyonggi University Graduate School) ;
  • Yang, Keun-Hyeok (Department of Plant.Architectural Engineering, Kyonggi University)
  • Received : 2016.12.12
  • Accepted : 2017.02.28
  • Published : 2017.06.20


The objective of this study is to seek a reliable mixture proportion for magnesium potassium phosphate composite(MKPC) mortars with a near-neutral pH value (below 9.5) and a relatively good compressive strength exceeding 30MPa. The main parameter selected was the molar ratios($M_{mp}$) of $MgO-to-KH_2PO_4$ which varied from 30.4 to 3.4. The setting time of the MKPC mortars tended to shorten with a decrease in $M_{mp}$ value. With regard to the strength development ratio normalized by the 28-day strength, the ranges measured in the mortars with an $M_{mp}$ below 7.9 were 50~61% at 1 day and 60~73% at 3 days, indicating a highly rapid early-strength development. With a decrease in $M_{mp}$, the formation of struvite-K crystal identified as a primary hydration product increased, which led to the decrease of the macro-capillary pores in micro-structures. For achieving the targeted requirements for pH value and compressive strength, the $M_{mp}$ needs to be selected as below 5.1.


Supported by : Ministry of Land, Infrastructure and Transport


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