Vitrobond Ingot Capping Compound

Vitrobond Ingot Capping Compound

Vitrobond is a mineral-filled, sulfur-based compound formulated for capping concrete test cylinders. It is easily melted, pours smoothly, possesses high compressive strength and gives consistent test results. Vitrobond has been used for many years by independent testing laboratories, pre-stressed concrete structures manufacturers and federal, state and local testing agencies. This compound is suitable for running compressive strength tests upon high strength concrete. 

Compressive strength exceeds 5,000psi (34.4kPa) at two hours and increases to 7,000psi (48.3kPa) at seven days. Ingots come in 50lb (23kg) cartons, each with ten 5lb ingots. Pieces break easily for melting to a pouring temperature of 280°–300°F (138°–140°C).

Physical strength ratings are 600psi tensile strength and 1,300psi modulus of rupture by ASTM C307 methods. The compound must not be heated above 320°F (160°C). Using excessive-release oil may affect cap strength.

Vitrobond offers the following advantages: 

• Ready-to-use—just melt and pour
• No mixing or possibility of low strength or erratic results from improper proportions
• Does not require controlled room temperature or humidity conditions during pouring of caps
• Does not require moist curing or other tedious handling procedures
• Not affected by dry cylinders
• Can be tested two hours after cooling
• Virtually no settling in the melting pot; thus, results are uniform from cylinder to cylinder

For the most consistent test results, it is suggested that the caps be applied using a vertical capper. Pour the molten VITROBOND on the base plate of the rig and promptly place the cylinder into the molten compound to a depth so that a cap of approximately 1/8" thick will be obtained. 

AASHTO T 231, ASTM C307, ASTM C287, ASTM C617