What is the common silica fume quality detection method?
Jul 30, 2024
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1. Rebound method
The rebound method is simple to operate, and can better reflect the uniformity of commercial silica fume, and the technical regulations of China's rebound method have been repeatedly revised for more than half a century, until the number was changed to JGJ/T23-2011 in 2011. The resilience method should be used to test the strength of commercial silica fume in batches. The commodity micro-silicon powder of the same acceptance batch shall be composed of the same components with the same strength grade, raw materials, age, maintenance conditions and the same production process and mix ratio, and there are strict regulations on the quantity of sampling.
2. Ultrasonic rebound synthesis method
Ultrasonic rebound synthesis method is a nondestructive testing method developed in the 1960s. In this method, resilience meter and concrete ultrasonic detector are used to measure the resilience value R reflecting the surface hardness of concrete in the same testing area of structural concrete, and measure the sound velocity v penetrating through the specimen by ultrasonic wave. Then, the compressive strength of concrete in the testing area is comprehensively estimated by using the established strength measurement formula, which can effectively reduce the influence of age and moisture content. The actual quality of structural concrete can be fully reflected by combining the advantages of rebound and ultrasound.
Practice has proved that compared with a single method, ultrasonic rebound synthesis method has the characteristics of high test accuracy and wide application range, and has been widely recognized by the engineering field, and has been widely used in China's construction, municipal, railway and highway systems.
3. Pull out method
Pulling out method is a method to detect the strength of concrete and it is a semi-damaged method. There are two methods: embedment pulling out method and post-loading pulling out method.
3.1 Embedment and withdrawal method:
When the concrete is poured, the anchor is buried, and when the concrete reaches a certain strength or age, the puller is installed to detect the strength of the concrete.
Suitable for the on-site control of concrete quality, such as deciding the appropriate time to remove the mold plate or add loads, deciding the appropriate time to apply or relax the pre-stress, deciding the appropriate time to lift and transport components, deciding the appropriate time to stop the wet heat maintenance or the appropriate time to stop the heat preservation during winter construction.
3.2 Post-installation and pull out method:
The post-loading pulling out method refers to drilling, grinding grooves, embedding anchors and installing pulling out instruments on the hardened concrete surface for pulling out tests, measuring the ultimate pulling out force, and testing the concrete strength according to the pre-established correlation between pulling out force and concrete strength.
4. Core drilling method
This method uses a special drilling machine to drill a core sample from the structural concrete to detect the strength of the concrete or observe the internal quality of the concrete. Because it causes local damage to structural concrete, it is a kind of semi-damaged field detection method.
