Pure clinker Portland cement
Gypsum is added to Portland cement clinker in appropriate amounts and then ground into four different grades: 425, 525, 625, and 725. This type of cement exhibits a 5-10% higher early strength compared to other types of Portland cement. It also demonstrates excellent resistance to frost and wear, making it ideal for high-grade concrete applications, particularly in critical civil engineering projects. 2. Ordinary Portland Cement 1) Concept Ordinary Portland cement, abbreviated as P·O, is a hydraulic cementitious material composed of Portland cement clinker, 6% to 15% of mixed materials, and an appropriate amount of gypsum. The quantity of mixed materials used depends on their level of activity. According to Chinese standards, when active materials such as granulated blast furnace slag, volcanic ash, or fly ash are added, the total weight should not exceed 15%, with no more than 5% being kiln dust (a fine powder collected from the exhaust of a rotary kiln). Alternatively, if inactive materials are used, the maximum allowed addition is 10%. Ordinary Portland cement is available in six strength grades: 275, 325, 425, 525, 625, and 725, and is widely used in the production of various mortars and concretes. 2) Technical Requirements The fineness of the cement must not exceed 10% when tested through an 80μm square sieve, otherwise it is considered non-conforming. The initial setting time should be no less than 45 minutes, and the final setting time should not exceed 10 hours. If the initial setting time is too short, the product is deemed defective. If the final setting time is too long, it is considered non-compliant. Volume stability must pass inspection; otherwise, the cement is classified as waste. Ordinary Portland cement is categorized into three main strength classes—32.5, 42.5, and 52.5—based on its compressive and flexural strength at 3 days and 28 days. Each class is further divided into normal and early-strength types. 3) Basic Performance and Application Ordinary Portland cement shares similar applications with standard Portland cement but has some limitations in specific uses. Despite this, it remains the most widely used cement type in the construction industry due to its versatility, cost-effectiveness, and reliable performance across a wide range of building applications. 3. Slag Portland Cement, Pozzolanic Portland Cement, Fly Ash Portland Cement Wall Fountain,Waterfall Fountain,Waterfall Feature Fountain,Curtain Water Fountain Guangzhou Dewy water fountain Technology Co., LTD , https://www.dewyfountain.com