混凝土圆柱盖

限制

In order to ensure accurate results when performing compressive strength testing of concrete test cylinders, 试验钢瓶的两端必须光滑, parallel 和 uniform bearing surface perpendicular to the applied axial load for accurate results. If the cylinder ends are not perfectly uniform 和 parallel to one another, the measured strength of the concrete becomes weaker due to built-up stress within the cylinder. Compliance specifications for the planeness 和 perpendicularity of test specimens is outlined in ASTM C39.

通常, when making test cylinders for compression testing, the ends of the cylinders do not meet the compliance specifications for the planeness 和 perpendicularity as outlined in ASTM C39. One of the most popular methods of correcting this is the use of capping materials, such as sulfur-based or gypsum cement capping compounds, which are melted in a melting pot 和 applied to the ends of the test cylinders to form a plane surface perpendicular to the specimen axis to evenly distribute 加载 forces. Specifications for the planeness 和 perpendicularity of specimens This procedure is outlined in ASTM C617 和 AASHTO T 231 specifications.

这些封顶化合物往往是经济的, 特别是在测试大量气缸时, 和, is often the preferred end treatment for cylinder ends because of their reliability 和 long-time use. Reliable strength results 和 consistent display of fracture patterns are predictable 和 well understood. In some cases, capping compounds are acceptable for testing high-strength concrete mixes.

Sulfur capping compounds tend to be the most widely used material for this application. It is typically comprised of a sulfur/mortar composition using additives like fly ash or plasticizers to modify strength, 材料的可用性和固化速度. Sultur-based capping compounds are produced in flakes for fast, 甚至融化, or solid ingots for convenient storage 和 h和ling.

硫基化合物所需的实验室设备
Equipment needed for the preparation 和 application of Sulfur-based capping compounds tend to be cost-effective 和 uncomplicated to use. Most equipment required tends to be a one-time cost as it can be used for years.

熔炉,
一个高品质的大熔炉， 比如洪堡提供的那些，使盖料均匀融化. 可更换的加热元件, 固定在锅的底部和侧面, provide even heat distribution for fast 和 甚至融化 of the capping compound. Their even distribution of heat prevents dangerous pressurization of the partially melted compound. They feature an adjustable thermostat to deliver close temperature control automatically from 100° to 320°F (37.8 ~ 160°C). Maintaining the correct temperature avoids overheating, 过度的烟雾, 和 damage to the properties of the capping material. Melting pots are available in multiple sizes to accomodate any size operation. The ideal melting pot capacity should produce enough capping compound to cap all the cylinders to be tested for a given day.

汽缸封口机,
一个汽缸盖， H-2952 or H-2925A, produces a cap of the correct thickness correctly aligned with the concrete cylinder. The heavy steel fixtures are precision machined for planeness 和 perpendicularity 和 typically bolted to a benchtop. Heavy-duty vertical cylinder cappers are used for applying capping compound to concrete test cylinders in preparation for compression tests. The cylinder capper simplifies the capping process by ensuring that the test cylinder end surfaces are plane 和 at right angles to the axis of the cylinder. The upright is used as a guide for positioning the cylinder. Molten capping compound is poured into the mold (plate); then the cylinder is placed on the capping material. After the compound is set, the capped cylinder is removed for testing.

温度计,
A rugged thermometer with a range of 400°F (204°C) or more, 和 with heat-resistant construction to withst和 harsh conditions.

金属桶,
一个金属勺子， H-2958, is used to pour the molten capping compound into the capper. The h和le should be long enough to reach the bottom of the melting pot easily.

安全设备,
如这些材料的SDS中所述, 眼睛, 皮肤, 并应采取呼吸防护措施, ASTM C617 calls for a fume hood vented to the outdoors.