1975 年 24 巻 263 号 p. 761-768
The main purpose of the present study is to obtain an epoxy resin mortar which can be used safely in environments below freezing point. The mechanism of curing of the binders used in the experiment consists of the ring opening of the epoxy radical by amine as the electron donor and the subsequent addition polymerization.
The tensile test specimens were briquets of ASTM C 190, while the bending test specimens were prisms of JIS R 5201 or prisms of 2×2×10cm. The compressive test specimens were fragments of prisms of JIS R 5201 or of cylinders of 2.5cm (diameter)×5cm (height). The aggregate used was absolutely-dried sea sand. The binder content was 15per cent.
The experiments to find (1) properties of binders, and (2) short period strength development were conducted using 20 kinds of test manufactured products at -6°C. As for (1), the viscosity ranged from 400∼557000cps, the gel time from 35∼161min, and the maximum exotherm temperature from -1∼+195°C. The consistency, stench, and exotherm profile at +4°C or -1°C were also examined. As for (2), the curing time was 1, 2, 4, 8, or 16 days. The strengths in 8 day's curing were 22∼130kg/cm2 (tensile), 63∼360kg/cm2 (bending), and 128∼645kg/cm2 (compressive), and it was possible to regard these value approximately as equilibrium values. The cured materials which showed good flexibility generally exhibited high strengths.
An epoxy resin mortar which showed the most prominent performance in these experiments was used for the experiments to find (3) long period strength development at -6°C, and (4) strength development at fluctuating temperatures. As for (3), the curing time was 0.5, 1, 2, 3, 4, or 6 months. The maximum strengths were 151kg/cm2 (tensile, 0.5 month), 417kg/cm2 (bending, 1 month), and 808kg/cm2 (compressive, 4 months). As for (4), the curing conditions were chosen from the combinations of -15°, -6°, and +10°C. Sufficient strengths for practical applications were obtained under all the curing conditions.