We use the basic formula if indirect inorganic polymerization, as follows
P = f (M + m)abc
(in which P = polymerization; M = mixture of clay and lime; m = rapid petrifying gel; abc = mixture, pressure and heat).

For each region of Viet Nam, we will examine the materials and the chemicals, utilized in the formula. We divide the South Viet Nam into 4 regions : Oriental Nam Bo, Western Nam Bo, Western Highlands and Southern Cost of Viet Nam.

The area includes 5 provinces : Dong Nai, Binh Duong, Tay Ninh, Binh Phuoc, Baria -Vung Tau and Ho Chi Minh city. These clay is made mainly of Kaolinite, coming from the weathering of shale and magmatic rocks. The clay of schists and shales has 30% of kaolin and others 50%. The half part of this clay shows 30% of illite, 10% of smectite and 10% of silt. Sometime it is rich in montmorillonite, like the core Upper Binh Duong, Binh Long and a part of Dong Nai. The red basaltic soil is made of silt and montmorillonite. The pale grey sandy soil of Oriental Nam Bo is made of Kaolin and illite, appearing as a good clay for polymerisation. In some contact with the black soil, it contains organic matter and smectite, where the polymerisation calls for much attention.
According to the basic formula, physical factors a,b,c must be highly considered. The various presence of clays in the soil must be treated saparately.
For the montmorillonite, smectite and vermiculit we must wipe out cracking of the materials by adding sand (more than 30%, up to 50%) and by adding an high ratio of lime.
With silty basaltic red silty soil, we prefer to add kaolin rich soil to create a good linkage.
With sandy soil in sand dune, we add 30% of kaolin (any colours)
As for m, we use a good gel, adding also a small amount of Portland cements and/or stabilizing acids.


The area accupies 4,000,000 hecta with an evenly flat topography made of silt and clay, with some high sand dunes. The soil is rich of acid and salty components, showing a rich part of organic matter which colours the soil in black.
Analysis os soil reveals the presence of smectite, vermiculite and montmorillonite. Kaolinite hardly reachs 30%; the neutral silt shows 50% and the remaining part occupies 20%, which is already dangerous.
For M, we must add an high ratio of lime, 50% are more of sand (from dune and from rivers) to strenghten the silt. Silica or organic gels are useful, as stabilizing acids, from which we would prefer H2SO4.
The polymerization does not reject acid, salty and organic soils. Therefore, we can use organic soils for building roads and houses for the countryside.

All sort of soils are present there. We may separate them into groups for building and road materials, as well as an agricultural construction soils.
As for red basaltic soil, we treated as in Nam Bo Oriental, with addition of coloured Kaolin and lime. As for sandy, silty and clayish soil on hilly parts, soil is ready for polymerization without adding any clay, because the clay appears to be Kaolinitic.
As for the presence of bentonite or swelling clay, we must add up to 50% of sand. Bentonite could be montmorillonite, smectite or vermiculite.
Weathering from shale give rise to kaolin and illite (neutral); from granite and granitic group, kaolin or bentonita; from andesite and dacite, kaolin with various colours. We must test rhe petrification of small samples before use.

The Western part is made of soils like the Western Highlands and we can apply formulas from them. The Western part is made of beach with white and coloured sand dunes.
With sand dune, we may add 30% of clay (kaolin) and 70% od sand for hardening. The ratio of lime in this mixture should be higher than usual.
Rapid hardening chemicals should be a sulfonate gel, but Portland cement is very good with small ratio
With materials for building in the salted water, the best polymerization shoul be with organic polymers, such as formadehyde malamine or acrylate, which are more expensive than lime

We have analyzed almost every group of soils in South Viet Nam. There are 90% of soils apte to be polymerization. Only 10% soils are not capable of polymerization, like red basaltic soil, sand dune, river sand. For these, we must add some more materials (clay, lime) or chemacals (gel, acids) to get formulas ready for polymerizations
It is appreciate to repeat here physical factors like mixture, pressure and heat appear to be very important to bring back good results.

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