An overview about concrete foam agent

2019-06-10 11:01:03

Information about foaming agent and its variants.

A foaming agent is a material that promotes foam formation, which is mainly divided into two kinds:  the surfactant and the foaming agent. When the Surfactant presents in small amounts, it can reduce the surface tension of liquids (reducing the work required to produce foams) or increase their colloidal stability by inhibiting the coalescence of bubbles.  While the foaming agent is a gas that forms the gaseous part of a foam.

Foamed concrete is a kind of special light porous concrete. In order to have air holes, you need a way to trap air in concrete before it starts to sink. Not the greatest traps are bubbles, or we can say foaming here. To create bubbles quickly and steadily, we need a foaming agent or chemical that creates these bubbles before you pour it into the plain concrete.

Foamed concrete foaming agent is a kind of substance that can make its aqueous solution produce a large number of foams when mechanical force is introduced into the air. This kind of substance is

surface active agent(surfactant) or surface active substance. The former includes anionic surfactant, cationic surfactant, non-ionic surfactant; the latter includes animal protein, plant protein, pulp iste liquid. Foamed concrete foaming agent is also known as cement foaming agent. Concrete foam agent refers to a kind of material that can reduce liquid surface tension and produce a large number of uniform and stable foam, which is used to produce foamed concrete additive. 

 

A new research about concrete foam agent.

By comparing the foam properties of different anionic surfactants with convenient materials and low price, sodium alpha-olefin sulfonate (AOS) with good foam stability is preferred as foaming component. A new foaming agent for foamed concrete is prepared by adding an appropriate amount of silicone foam stabilizer (zt-1) and thickening material carboxymethyl cellulose (CMC).

 

(1) By comparing four different anionic surfactants with the same solution concentration, scientists find that the foaming capacity of AOS is the strongest, followed by K12, AES and LAS. In terms of foam stability, AOS is also superior to the other three anionic surface activities and the optimal concentration of AOS solution is 0.80%.

 

(2) When 0.80%AOS foaming agent mother liquor is mixed with 0.20% organic silicon foam-stabilizing agent zt-1, the foam reached the optimal stability and the 1-h settlement distance is 4.8mm and the 1-h yield is 38.4 ml.

 

(3)On the basis of modifying AOS with organic silicon foam-stabilizing agent zt-1, the foam is further modified with thickened material carboxymethyl cellulose CMC. It is found that when the dosage is 0.020%, the foam performance reaches the optimal level, the foam multiple being 37.5 times, the 1-h settlement distance being 1.8 mm, and the 1-h secretion water being 26.1 ml. 

 

(4) The new foaming agent is applied to the preparation of 300~500 grade low-density foamed concrete, and the products showed good mechanical and thermal properties. The 28d compressive strength of class 300 foamed concrete reaches 0.82mpa, then the thermal conductivity is 0.062w/(m·K). The 28d compressive strength of class 400 foamed concrete reaches 1.3mpa, and then the thermal conductivity is 0.075w/(m·K). The 28d compressive strength of class 500 foamed concrete reaches 1.9mpa, and then the thermal conductivity is 0.087w/(m·K).

 

All of this being said, the results showed that the foam surface prepared by the new foamed concrete foaming agent is fine, shiny and stable. With a foaming multiple of 37.5 times, a settlement distance of 1.8 mm at 1 h, a displacement of 26.1 ml at 1 h, the foam’s height still remains more than 50% at 48 h. The foaming agent is applied to prepare low density foamed concrete.

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