Addittivi tal-Konkrit Ħfief | Aġenti tar-ragħwa ta 'prestazzjoni għolja għall-konkrit ċellulari
Any cementing material, including cement and magnesite, has an initial setting time, especially for the most widely used ordinary portland cement. The initial setting is mostly later than 45 minuti. If the foaming agent has poor stability, cement and other cementitious materials have not yet set, and the foam has collapsed, the foam will not be able to form pores in the concrete. B'mod ġenerali, the minimum requirement for foam stability is to make the foam stabilization time longer than the initial setting time of the gelling material by 10-20 minuti. Because the initial setting time of various gelling materials is not consistent, ir-rekwiżiti għall-ħin ta 'stabbilizzazzjoni tal-fowm huma wkoll differenti. B'mod ġenerali, the foam stabilization time for fast gelling materials can be shorter, and the foam stabilization time for slow gelling materials should be as long as possible. Even if the same kind of gelling material has a different temperature, il-ħin tal-issettjar inizjali tiegħu huwa differenti, u l-bidla hija pjuttost sinifikanti. Per eżempju, ordinary silicon cement may set in less than 40 minuti fis-sajf.
But it will not set in 80 minuti fix-xitwa kiesħa hawn taħt 5 ° C. Għalhekk, it is impossible to have a uniform specific standard for the stabilization time of the foam, and it should be determined according to the situation. Biex tadatta r-ragħwa għall-ħtiġijiet ta 'diversi kundizzjonijiet ta' użu, it should be allowed to stabilize as long as possible. B'mod ġenerali, the stabilization time of the foam should meet the following requirements;
1. When used in Portland cement without setting accelerator, the stabilization time should be more than 60min; the ideal maximum is more than 3h;
2. When used in fast-setting cement such as sulphoaluminate cement, siment tal-alumina għoli, siment tal-aluminat tal-ħadid, fast setting Portland cement, the stabilization time should be more than 30min, preferably more than 60min;
3. Meta jintuża fis-siment tal-manjeżju, the foam stabilization time should be higher than 40min, preferably higher than 80min;
4. When used for gelling materials doped with a large amount of filler or active waste residue such as fly ash, il-ħin ta 'stabbilizzazzjoni tal-fowm għandu wkoll jiġi estiż. The more significant the amount of padding or active waste residue, l-itwal il-ħin ta 'stabbilizzazzjoni tal-fowm.
The specific foam stabilization time should be determined through a small test. The principle is that the mould does not collapse after pouring, the pores are not connected after formation, and the law of excessive deformation is not determined. The vital principle is that the longer the stabilization time, l-aħjar.
Iktar ma jkun kbir id-dijametru tal-bużżieqa, l-aħjar. It should be above 1mm.
The pores have the same requirements for the pore size, as well as the requirements for the bubble diameter. Many producers and some experts have misled the pursuit of a fine foam with a pore size of 0.1mm. It is because physical foaming cannot make a foamed concrete if the foam diameter is large, and the stability of the foam is poor. L-istess materja prima u formula, l-istess tagħmir u teknoloġija, ibdel biss id-dijametru tal-fowm, the compressive strength of foam concrete with 1mm foam diameter is at least 20% higher than that of foam concrete with 0.1mm foam diameter. Għalhekk, it is wrong to pursue a small bubble diameter of more than 0.1mm, which is a misunderstanding in the production of foam concrete and should be corrected.
Aktar ma tkun baxxa r-rata ta' fsada tal-fowm, l-aħjar, evita li tuża fowm tal-ħalib.
Kif issemma qabel, foams are divided into milky foams with more water and less foam and creamy foams with more water and less foam. The milky foam is unqualified and inferior and cannot be used.
After the foam is confident, it gradually exudes water. Il-fsada tiegħu tinkludi żewġ partijiet:
1. Bleeding of foam liquid membrane. This part of the water is secreted from the liquid film. It is the water that the liquid film emits under the combined action of gravity drainage, drenaġġ tat-tensjoni tal-wiċċ, u drenaġġ tal-qerda tal-membrana tal-fluwidu. Eħxen il-film likwidu tar-ragħwa, iktar ma jkun għoli l-fsada; the faster and more the foam collapses, iktar ma jkun għoli l-fsada.
2. Inter-bubble water between foams. This part is water that does not form a bubble liquid film. L-agħar il-prestazzjoni tar-ragħwa tal-aġent tar-ragħwa u l-magna tar-ragħwa, the more inter-bubble water cannot create a foam liquid film. They are water that does not become air bubbles.
When the bleeding rate of the foam is very high, se jkun irqiq daqs meraq f'wiċċ l-ilma, flowing randomly and cannot be piled up, and the amount of water in the foam is large. When this foam is added to the cement slurry, id-demel likwidu tas-siment isir irqiq ħafna. Xorta, the foam is minimal, the volume of the mud is small, and the density of the foamed concrete is very high, which is not technically desirable.
Għalhekk, fowm tal-ħalib ma jistax jintuża. The appearance of the foam that meets the technical requirements should be sponge-like fine vesicles, piled up like white clouds and like bouncing cotton, u mhux se tgħaddi bl-addoċċ. The water content of this foam is minimal. This shows that its foam liquid membrane bleeds little, the foam is not comfortable to rupture, hemm ftit ilma bejn il-bżieżaq, and the amount of bubbles is significant, and most of the volume is bubbles. What needs to be emphasized here is that the sponge-like foam must be small bubbles with a bubble diameter of less than 1mm, not large bubbles of several millimetres or even tens of millimetres. Giant bubbles are easy to pile up, and they are like white clouds, iżda minħabba li d-dijametru tal-bużżieqa huwa kbir wisq, huwa wkoll mhux kwalifikat.
The requirement for low water bleeding of the foam is mainly to ensure the number of bubbles in the foam and the porosity of the foamed concrete, jiġifieri, to ensure the density of the foamed concrete.
Cie-China.org huwa l-fornitur ewlieni ta 'addittivi tal-konkrit tal-fowm li jipprovdi aġent tar-ragħwa tal-konkrit, superplastiċizzant,li jsaħħaħ is-saħħa tal-konkrit tal-fowm għall-konkrit ħafif, Blokki CLC. Jekk qed tfittex aġent tar-ragħwa, jekk jogħġbok tħossok liberu li ikkuntattjana.