First of all, fly ash, the active effect of fly ash refers to the chemical effect produced by its active ingredients. The activity of fly ash depends on the reaction capacity of the pozzolana www.biquge.info that is, the chemically active SiO2 and Al2O3 in the fly ash react with Ca(OH)2 to produce reaction products such as calcium silicate hydrate and calcium aluminate hydrate produced by cement hydration, which can be used as part of the cementitious material to play a reinforcing role. The volcanic ash reaction begins when the calcium hydroxide precipitated from the hydration of the cement adsorbs to the surface of the fly ash particles and can continue for a considerable period of time after 28 days. ”

Li Ruoyu spoke with relish, but a beautiful woman in the audience was dozing off constantly, and that beauty was naturally Zhou Yuwei, although Li Ruoyu was the man she loved, and she should love the house and Wu, but she really couldn't listen to these theories, after all, she was different from these students, she was a police officer and not a student of building materials.

Li Ruoyu couldn't help but laugh when she saw Cao Xiaoxiao's eyelids fighting, but the students' reactions were good, and they listened attentively one by one, and some were still taking notes with pens.

So Li Ruoyu continued: "The second is the morphological effect, the morphological effect of fly ash refers to the effect of fly ash powder by the physical properties such as the appearance and morphology, internal structure, surface properties and particle gradation of its particles. The fly ash particles formed during high-temperature combustion, most of which are glass beads, are spherical particles with a relatively smooth appearance, and are composed of silicon-aluminum glass. Because the spherical particles have a smooth surface, they can play the role of ball lubrication after being mixed into concrete, and can not increase or reduce the mixing water consumption of concrete, and play a role in reducing water, but another characteristic of fly ash in morphology is its inhomogeneity, if the particles containing coarse, porous, irregular shape are dominant, then not only lose the superiority of all physical effects, but also damage the original structure and performance of concrete, what is obtained is a negative effect, and this form of fly ash should often affect the play of other effects. ”

"Of course, in addition to the first two effects, there is also the microaggregate effect. The micro-aggregate effect of fly ash refers to the characteristics of the fine particles in fly ash that are evenly distributed in the cement slurry, filling pores and capillaries, improving the pore structure of concrete and increasing the compactness. The superior performance of fly ash micro-aggregate is reflected in the following points. First, the glass beads themselves are very strong. Second, the micro-aggregate effect significantly enhances the structural strength of the hardened slurry. The microhardness of the fly ash hydration gel formed at the interface between fly ash and cement slurry is greater than that of cement gel. This shows that fly ash has a reinforcing effect on the interface between the slurry and the aggregate in the concrete, which is the weakest joint. Third, fly ash particles are well dispersed in the cement slurry, which helps to fill and refine the pores and capillaries in concrete."

"These three effects of fly ash are coexisting in one and are mutually influential, should not emphasize a certain effect and ignore other effects, a certain performance of concrete, under certain conditions, may play a leading role, in other conditions, another performance of concrete, may be another effect to play a leading role, should be analyzed on a case-by-case basis. ”

"The application of fly ash is also very particular, and if it is used well, it will produce some good results. Construction engineering and technical personnel know that many special properties of concrete can be obtained by adding concrete admixtures, such as the correct use of admixture technology can sometimes achieve the corresponding effect, not only to reduce the cost of concrete production but also to avoid the admixture on the performance of the adverse effects. ”

"For example, compared with concrete admixtures, concrete admixtures can play a lot of roles, one is the water reduction function, high-quality fly ash because of the spherical appearance, with a certain water reduction effect is easy to understand, the concrete with a high-efficiency water reducer and then mixed with mineral admixture will have a better water reduction effect, especially in the ultra-low water-glue ratio where the chemical superplasticizer is powerless, the mineral admixture can also have a certain water reduction function. ”

"The second is the early strength function, because the ultra-fine admixture is very small in particles, it is filled between the larger particles to make them overlap with each other as soon as possible, and the hydration speed is fast and the early strength effect is good. The third is the retarding function, when the concrete is mixed with more admixtures such as fly ash, mineral powder, coal gangue fine powder, etc., the cement clinker in the concrete mixture unit space is reduced accordingly, and the early hydration products are less, and the number of hydration products is not enough to effectively link the particles with each other to make the concrete mixture retarding, so a certain retarding effect can be obtained by reasonably selecting the variety and quantity of mineral admixture. ”

"Fourth, the micro-expansion function, bauxite + gypsum + aluminum sulfate is a concrete expansion agent, in order to reduce the cost of expansive mineral admixture, make full use of industrial waste residue, you can use natural coal gangue or fly ash containing more aluminum components instead of bauxite to prepare concrete admixture with micro-expansion function, or add light burnt magnesium with certain activity or waste residue during the production of magnesium when grinding mineral admixture, such as magnesium slag and other materials. Fifth, waterproof function, the cementitious material mixed with high-efficiency superplasticizer and micro-expansion admixture can form cement stone with good compactness, and it can be completely prepared without adding any organic waterproof agent, etc.

When Li Ruoyu finished speaking, he found that Zhou Yuwei had slept very sweetly!

Liu Lei on the side smiled and said: "Li Ruoyu, this Miss Zhou, must be your girlfriend, right? I really envy you, I didn't expect that you were still very hidden in the past, and you were silent in school, but now you are making a lot of money, and you have found such a beautiful girlfriend!"

Li Ruoyu smiled bitterly: "Xiaolei, that's not the case! Let me tell you, Zhou Yuwei's father is the boss of our public security system in Huhai City! Who dares to soak her? Besides, her father doesn't have much affection for me, so it's impossible for us now." Moreover, I already have a fiancée, in my hometown, her name is Shen Lu!"

Liu Lei sighed and said: "Ah, that's a pity! Miss Zhou's background is so strong, it's a pity! Otherwise, it will definitely help your career! But you are also really, you don't care about your old classmates when you get rich, right, if I didn't happen to meet you this time, I don't know! By the way, when will you invite me to drink happy wine?"

Li Ruoyu smiled bitterly: "It's still early! It's you, you should be able to think about lifelong events, hehe1"

Liu Lei stretched out her jade hand and slapped Li Ruoyu, and scolded with a smile: "Begging for a beating! I'm not in a hurry, besides, it all depends on fate! Forget it, don't talk about this, our class should have a class reunion, it's been three years since graduation, you should contact and communicate! By the way, when the time comes, you, the big boss, will have a treat!" (To be continued.) )