Analysis of raw material testing for construction projects:
Construction project raw material testing is the core link to ensure the quality of building construction and guarantee the average quality of raw materials. At present, the construction project raw materials mainly include cement, crushed stone, sand, fly ash, etc. Each raw material has a corresponding national industry use standard, and the main points of its testing are mainly its own service life and load-bearing quality, which can meet the requirements of long-term construction use. For the use of raw materials process, also to carry out targeted testing, in different links to develop the corresponding use of testing standards to ensure that they meet the national building construction requirements, for some of the controversial raw materials can be a new round of assessment, so as to protect the construction quality of building projects.
Elements of raw material testing work for ready-mixed concrete production:
In general, different building construction projects, its corresponding ready-mixed concrete production raw material testing indicators are not exactly the same, there will be certain differences in testing requirements. We should strictly follow the industry standards for raw material production, test different types of raw materials one by one, and ensure that the whole process of testing is accompanied by professional personnel, according to the test results for the procurement of raw materials to put forward the corresponding guidance. The testing process should pay attention to the details of the processing, the use of raw materials for ready-mixed concrete production standards are more demanding, the testing process is more complex, the need for cooperation between various audit departments, to eliminate blind trust caused by the construction of raw materials that do not meet the standards into the construction site.
Rapid testing techniques for ready-mixed concrete production raw materials are explored:
1. Sand testing technology
The rapid detection of sand can be done by first visually inspecting the fineness of the sand, initially determining the water content in the sand by touching it with the hand, rubbing the sand with the hand, and judging the quality of the overall material according to the traces of mud content of the sand grains in the hand. Or put the sand to be tested into clear water and analyze the sand quality test according to the turbidity of the water. Separate and store different kinds of sand and gravel, as well as the same kind of sand with different fineness. Different kinds of sand and gravel, there are certain differences in their rapid detection means, for the rapid detection of chloride ion content in sea sand work, usually using micro reagent paper or chloride ion content rapid determination instrument to carry out; while the mechanism of sand with the help of magnifying glass, through the naked eye on the sand and gravel particle identification and the shape of the particle ball.
2. Cement testing technology
Cement is the main component in ready-mixed concrete, which can mix the stones, sand and other components in the material and play the role of mixing agent. The color of high quality cement is often dark gray or light green, the more the color leans towards green, the higher the quality of the cement is proved; the more the color leans towards gray, the more the cement is proved to have too much slag micronized powder mixed in it. The rapid detection of cement work, you can use the hand to perceive that it does not have larger particles, or through the chemical reaction experiment, that is, the use of phenolphthalein indicator on the quality of cement paste detection, if it does not show a more obvious red, the cement is of poor quality. For the concrete cement just out of the field, its temperature is higher, and through the fusion with the admixture experimental determination, can be derived from the cement quality test results.
In the cement selection link, there are many other considerations. One, the construction unit should be discriminated according to the content on the cement certificate when selecting ready-mixed concrete cement, and ensure that the cement qualification certificate is provided by professional cement testing units with certain persuasive power. Second, in the same quality of the choice of issues, as far as possible to choose a more inexpensive cement, to protect the economic benefits of the construction unit. Third, when the conditions allow, the composition of the cement can be analyzed through experiments, as well as the cement bonding time, the degree of delicacy, specific strength and other information, according to the actual requirements of the project works, choose the most suitable concrete materials.
3. Crushed stone testing technology
The method of rapid testing of crushed stone is mainly to visually determine the size and shape of the crushed stone, and to store different kinds of crushed stone separately, and for different states of the same kind of crushed stone, such as some of the crushed stone has pores visible to the naked eye, it needs to be stored separately. When selecting stones in the stone quarry, the particle gradation of the stones is tested. For the shale and yellow skin particles in the stone should also be carefully tested, where there are usually two kinds of yellow skin particles, if there is water rust on its surface but no attached mud, then this yellow skin particles will not affect the adhesion of crushed stone and can be used; but if there is yellow mud on its surface, then the quality of this yellow skin particles is poor, which greatly affects the adhesion of crushed stone and reduces the quality of ready-mixed concrete. Before the crushed stone material is transported from the quarry to the construction site, the grade, needle shape and crushing value of the crushed stone stone should be analyzed to clarify the actual weight of the stone material. Considering that there will be some variability even in the crushed stone produced in the same area, a certain amount of crushed stone should be selected for testing to reduce the influence of chance on the test results. In the crushed stone stone structure calculation link, should calculate the corresponding figures, the real number can reflect the actual situation of ready-mixed concrete production of raw materials crushed stone rapid detection.
4. Fly ash detection technology
One, for the fine degree of fly ash detection, the principle of this method of detection is that when the fly ash moisture is more, its degree of activity will increase, so as to analyze the situation of the moisture it contains, to determine whether it meets the construction standards, the advantage of this detection method is that its operation is less difficult, and intuitive, can directly reflect the quality of fly ash. Second, the use of instruments capable of determining the water content of fly ash testing under the auxiliary function of instruments and equipment, the advantage of which is the higher accuracy, but the experiment requires a certain cost. Third, through chemical reaction experiments to determine the water content of fly ash, the operation of this method is more difficult, requiring staff with a certain degree of operating experience, and to have the corresponding technology and conditions to support. Therefore, this testing method is not common in practice, only when the construction project has clear requirements for the quality of construction, will use this method for rapid testing of fly ash.