Pure clinker Portland cement
Gypsum is added to Portland cement clinker in appropriate amounts, and the mixture is 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 Portland cements, along with excellent resistance to frost and wear. It is ideal for producing high-grade concrete and is commonly used in significant civil engineering projects that require superior performance. 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 added 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 used, the total addition should not exceed 15% by weight. No more than 5% of kiln dust (a dry powder collected from the kiln exhaust during production) can be included, or up to 10% of inactive materials may be added. Ordinary cement is available in six strength grades: 275, 325, 425, 525, 625, and 725, making it widely used in various mortars and concretes. 2) Technical Requirements The fineness of ordinary Portland cement must not exceed 10% passing through an 80 μm square hole sieve; otherwise, it is considered non-conforming. The initial setting time should not be earlier than 45 minutes, and the final setting time must not exceed 10 hours. If the initial setting time is not met, the product is considered waste. If the final setting time is not satisfied, it is classified as non-conforming. The volume stability must pass inspection, otherwise it is rejected. Ordinary Portland cement is categorized into three main strength grades—32.5, 42.5, and 52.5—based on compressive and flexural strengths at 3 and 28 days. Each grade is further divided into normal and early-strength types. 3) Basic Performance and Application Ordinary Portland cement shares similar applications with Portland cement but has some limitations in specific uses where other types might be more suitable. As a result, it remains the most commonly used cement in the construction industry due to its versatility, cost-effectiveness, and reliable performance across a wide range of building and infrastructure projects. 3. Slag Portland Cement, Pozzolanic Portland Cement, Fly Ash Portland Cement Dry Floor Fountain,Musical Fountain,Outdoor Water Features,Music Dancing Fountain Guangzhou Dewy water fountain Technology Co., LTD , https://www.dewyfountain.com