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As well known, sulfate and phosphate are widely used additives for MOC products. In this work, the influence of FeSO4 and KH2PO4 on the properties of magnesium oxychloride cement (MOC) such as compressive strength, water resistance, thermal stability, composition and micro structure were studied in detail by using material testing system (MTS), X-Ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), respectively. The results show that both FeSO4 and KH2PO4 incorporation can benefit the formation of gel-like 5Mg(OH)2·MgCl2·8H2O (P5) and the water resistance of MOC. However, the FeSO4 and KH2PO4 incorporation can downgrade the thermal stability and the mechanical strength. The influence of KH2PO4 is more obvious than that of FeSO4. In addition, the hindering hydration of MgO caused by sulfate and phosphate ions result in reduction of the hydration product, while the double hydrolysis reaction between Fe2+ and MgCO3 leads to slight increase of the resultant in the slurry of MOC. © 2015 Elsevier Ltd. All rights reserved.

As well known, sulfate and phosphate are widely used additives for MOC products. In this work, the influence of FeSO4 and KH2PO4 on the properties of magnesium oxychloride cement (MOC) such as compressive strength, water resistance, thermal stability, composition and micro structure were studied in detail by using material testing system (MTS), X-Ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), respectively. The results show that both FeSO4 and KH2PO4 incorporation can benefit the formation of gel-like 5Mg(OH)2·MgCl2·8H2O (P5) and the water resistance of MOC. However, the FeSO4 and KH2PO4 incorporation can downgrade the thermal stability and the mechanical strength. The influence of KH2PO4 is more obvious than that of FeSO4. In addition, the hindering hydration of MgO caused by sulfate and phosphate ions result in reduction of the hydration product, while the double hydrolysis reaction between Fe2+ and MgCO3 leads to slight increase of the resultant in the slurry of MOC. © 2015 Elsevier Ltd. All rights reserved.

As well known, sulfate and phosphate are widely used additives for MOC products. In this work, the influence of FeSO4 and KH2PO4 on the properties of magnesium oxychloride cement (MOC) such as compressive strength, water resistance, thermal stability, composition and micro structure were studied in detail by using material testing system (MTS), X-Ray diffraction (XRD), thermogravimetry and differential scanning calorimetry (TG-DSC), scanning electron microscopy (SEM) and mercury intrusion porosimetry (MIP), respectively. The results show that both FeSO4 and KH2PO4 incorporation can benefit the formation of gel-like 5Mg(OH)2·MgCl2·8H2O (P5) and the water resistance of MOC. However, the FeSO4 and KH2PO4 incorporation can downgrade the thermal stability and the mechanical strength. The influence of KH2PO4 is more obvious than that of FeSO4. In addition, the hindering hydration of MgO caused by sulfate and phosphate ions result in reduction of the hydration product, while the double hydrolysis reaction between Fe2+ and MgCO3 leads to slight increase of the resultant in the slurry of MOC.

For elaborating the research significance, goal, content and representative results of the concrete marine field exposure experiments all over the world, we have collected a large number of research literature since 1905. The longest exposure test for concrete has reached 62 years and, most importantly, concrete exposure experiments have made great contributions to the establishment of three classical chloride diffusion models such as DuraCrete model, Life- 365 model and ClinConc model. And the comparison with foreign countries shows that concrete marine field exposure sites in China should adhere to long-term research with continuous tracking tests, for purpose of improving the durability evaluation method and life design theory of concrete structures in the harsh marine environment. Moreover, by analyzing the chloride content in the RC components after 42 months of exposure in the submerged zone in South China Sea, the diffusion depth of the chloride exceeds 40 mm, and the distribution of chloride content with diffusion depth is quite consistent with the chloride diffusion model established by Yu.

For elaborating the research significance, goal, content and representative results of the concrete marine field exposure experiments all over the world, we have collected a large number of research literature since 1905. The longest exposure test for concrete has reached 62 years and, most importantly, concrete exposure experiments have made great contributions to the establishment of three classical chloride diffusion models such as DuraCrete model, Life- 365 model and ClinConc model. And the comparison with foreign countries shows that concrete marine field exposure sites in China should adhere to long-term research with continuous tracking tests, for purpose of improving the durability evaluation method and life design theory of concrete structures in the harsh marine environment. Moreover, by analyzing the chloride content in the RC components after 42 months of exposure in the submerged zone in South China Sea, the diffusion depth of the chloride exceeds 40 mm, and the distribution of chloride content with diffusion depth is quite consistent with the chloride diffusion model established by Yu.