Characteristics of Hydration and Correlation on Cement-Based Thermal Insulation Material

Abstract

Cement-based thermal insulation material was manufactured using OPC, lime, anhydrite, and CSA cement in this study. The morphology and physical properties of the material were analyzed using XRD. All samples had ettringite, Ca(OH) 2 , and CaCO 3 crystals. The XRD peak intensity of the ettringite and Ca(OH) 2 slightly increased with an increase in curing time from 3 to 7 days. The compressive strength values at 28 days of specimens 1-8 were in the range of 0.25-0.32 MPa, and the compressive strength values of specimens 3-8 were > 0.3 MPa. The coefficients of correlation between compressive strength and apparent gravity at 7 days and those between compressive strength and ettringite/Ca(OH) 2 XRD peak intensity at 28 days were above 0.8. That is, the compressive strength exhibited an influence on apparent gravity at 7 days and on hydrate at 28 days. The thermal conductivity of all specimens was 0.041-0.045 W/mK, and the highest value of thermal conductivity was shown by specimen 5. The coefficient of correlation between apparent gravity and thermal conductivity was 0.84. It was concluded that control of raw materials and hydrates must be considered for manufacturing of insulation materials. The cement-based thermal insulation material in this study could be used in construction fields.

Using Fumed Silica to Develop Thermal Insulation Cement for Medium–Low Temperature Geothermal Wells

“…(1) High CSs are not required for TIC used in building external walls. The CS of the most developed TIC for buildings is less than 2.0 MPa, or even less than 0.3 MPa [ 19 , 20 ]. However, the CS of geothermal cement is generally required to be greater than 6.9 MPa for 24 h [ 21 , 22 ].…”