AU666706B2

AU666706B2 - Flexibility enhancement agent and method of use

Info

Publication number: AU666706B2
Application number: AU35121/93A
Authority: AU
Inventors: Gerhard Schilling
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-03-11
Filing date: 1993-03-11
Publication date: 1996-02-22
Anticipated expiration: 2013-03-11
Also published as: AU3512193A

Description

7667 0 P/00/011 Regulation 3.2

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AUSTRALIA

Patents Act 1990 COMPLETE SPECIFICATION FOR A STANDARD PATENT 0,0*00 o 0 'C O' Name of Applicant: Actual Inventor: Address for Service: GERHARD SCHILLING Gerhard Schilling TREVOR DREDGE ASSOCIATES Patent Trade Mark Attorneys 13th Floor, 379 Queen Street BRISBANE, QLD, 4000 (GPO Box 1339, BRISBANE, 4001) "Flexibili't Enhancement Agent and Method of Use" Australian Patent Application No.

1279 filed 11 March, 1992.

ft r l a 0000 Invention Title: Details of Associated Provisional Application No: c The following statement is a full description of this invention, including the best method of performing it known to me: 2 THIS INVENTION relates to a flexibility enhancement agent which can be added to finely divided granular material along with cement powder to improve the cured product and in particular, but not limited to a flexibility enhancement agent suitable for stabilising soils.

In conventional road or pavement formation, it is important that the foundation of the road or pavement be sufficiently stable to resist erosion or other damage due to wear. Considerable time is wasted and expense incurred in construction of road or pavement foundations using conventional techniques. Often unstable materials are removed and replaced with expensive quarry materials in an effort to combat soil erosion and create a stable base.

Similarly, construction of embankments, revetment walls or railway track beds involve soil replacement. In summary therefore, it is customary for unstable materials to be i removed and stable materials imported to enable an erosion resistant construction to be achieved.

Similar problems arise in other situations, for 20 example, in the general building industry, various products are available which permit the erection of buildings or other shelters in a rapid and efficient manner. Concrete products in particular are suitable for this purpose, such products enabling the fabrication of prefabricated building panels, blocks, or other parts which may be subsequently erected to form buildings, the whole arrangement is relatively expensive and in the case of concrete walls, the walls are heavy requiring special equipment for erection.

3 Moreover, procedures involved and materials required are not readily available in isolated areas and as a consequence, the costs in these areas can become prohibitive.

It is an object of the present invention to alleviate at least to some degree the aforementioned problems associated with the prior art.

In one aspect therefore, the present invention resides in a flexibility enhancement agent to improve the flexibility and reduce the tendency of cracking or S* shrinking in aggregates of finely divided granular material 0 mixed with cement powder and prepared while wet and allowed 0 0 to cure, the enhancement agent in use, being mixed with oi 0 0 9cement powder and the granular material prior to curing and reacting therewith so that after curing, the aggregate 0. includes an interstitial relatively flexible matrix bonding the granular material. The agent comprises first and second parts, the first part comprising a liquid formed e •e from compounds including sodium, calcium, magnesium, o 20 potassium, ammonium ion compounds, chlorides, carbonates and water, and the second part comprising a liquid made from compounds including silicates, sodium and water. The magnesium compound is present in the first part in the range of 3% to 6% by weight, the ammonium compounds in the range of 5% to 9% by weight, the calcium compounds in the range of to 1.5% by weight, the potassium compounds in the range of to 1.2% by weight, the chloride compounds 4N in the range of 12% to 21% by weight, the carbonate i Ii 4 compounds in the range of 4% to 7% by weight, water in the range of 52% to 65% by weight and sodium making up the remainder.

In another aspect, the invention resides in a method of stabilising finely divided granular material including mixing the granular material with cement powder, water and the said flexibility enhancement agent to form a mixture which, when allowed to cure, results in the finely divided granular material being adhered together to form a stabilised aggregate having greater flexibility than if the agent was omitted.

In a further aspect, the invention resides in a 4 •~4 stabilised aggregate of finely divided granular material, 4ei 4 cement powder and the said flexibility enhancement agent formed as a reactive mixture and allowed to cure, the stabilised aggregate having a greater flexibility and reduced tendency to cracking and shrinkage than if the agent was omitted.

06 The present invention thus provides an agent for 20 addition to cement and soils or other like materials for the preparation of a stabilised product.

In a particularly preferred form, it is preferable that for the first part the magnesium compound comprise 4% by weight, the ammonium compound 7.4% by weight, the chloride compound 16.3% by weight, the carbonate 5.6% by weight, the calcium compound 1.2% by weight, the potassium compound by weight, the water 60% by weight and the sodium compound making up the remainder. Suitably the )U ammonia is available and present in ammonium salts and chlorides present as both volatile and non-volatile chlorine with the ammonium salts and chlorides being present at 4.6% and 11.7% by weight respectively.

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The second part which typically functions as an activator solution has a content of silicate of about by weight as silicon dioxide or other functionally equivalent compounds with balance of water. The resultant liquid preferably has specific gravity of 1.12 and a PH of approximately 9.

Typical compounds which can be employed in the first part can comprise magnesium, calcium and ammonium chlorides or carbonates and typically, ammonium chloride, sodium chloride, magnesium chloride, calcium chloride and sodium carbonate as well as perhaps potassium hydrogen carbonate aI can be employed.

Preferably, the ammonium chloride comprises sal Sammoniac, technical grade powder present in the first part !in the range of 5% to 12% by weight and suitably 7.4% by Srt., r weight.

The sodium chloride preferably comprises common salt present in the range of 14% to 20% by weight and suitably 15.3% by weight. The calcium chloride suitably comprises flake technical grade present in the range of to by weight and preferably 1.2% by weight. The magnesium chloride suitably comprises hydrated 6H 2 0 technical grade present in the range of 3% to 6% by weight and suitably 4% pY' by weight. Potassium hydrogen carbonate suitably comprises i i hydrated 1.5 H 2 0 technical grade present in the range of to 1.2% by weight and preferably by weight. The sodium carbonate suitably comprises anhydrous soda ash or hydrated 10H20 washing soda present in the range of 4% to 7% by weight and suitably 5.6% by weight. Typically, the agent of the first part is formed by mixing the above components with the washing soda added last and tumble mixed throughout.

In order that the present invention can be more readily understood and be put into practical effect, reference will now be made to the following examples of preferred embodiments of the invention and the drawings and wherein:- Figures 1 to 4 are graphs illustrating comparative 15 tests dealing with application of the present invention to i stabilisation of sands; and SFigures 5 to 7 are graphs illustrating comparative tests dealing with application of the present invention to Ssilty, sandy clay.

The present invention primarily relates to a flexibility enhancement agent, use of the agent and aggregate formed from use of the agent, the aggregates formed are typically in the form of building products, foundations and so forth. The agent is a mixture of selected chemicals which the applicant has found improve the flexural strength of stabilised soil or concrete while at the same time reducing or inhibiting shrinkage. The following table illustrates typical constituents of one

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7 preferred form of agent suitable for applying the present invention to stabilisation of soils.

Chemical Spec. Smelting Point Norm. State Gravity Ammonium Chloride 1.53 37.2/100g Solid (NH4C1) at 20 dec. C Carbon Soda Diox. 2.533 7.18/100g Solid (Na2C03) at 0 dec. C Calcium Chloride 2.15 59.5/100g Solid (CaC12) at 0 dec. C Magnesium Chlor. 1.56 28.1/100g Solid (MgCl2 6H20) at 0 dec. C Silicic Acid Soda 2.61 -Liquid As can be seen, the agent typically includes sodium silicate and a source of ammonia and due to the highly reactive nature, the components are typically stored as a 4Ij:". two pack in liquid form with the first part typically comprising the following constituents.

Constituents by Weight Sodium Chloride 49.0% Ammonium Chloride 22.0% Magnesium Chloride 12.3% i Sodium Carbonate 16.6% While the second part comprises:- Sodium Silicate 22% of total It will be appreciated that the above are only exemplary and the functional equivalents of any constituent can be employed. For example, potassium carbonate can be used instead of sodium carbonate. The reaction which occurs when the parts of the agent are mixed with soil and cement powder in the order of 4% cement powder and .2%

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p.- 114.1* IIa aI I a. Ia a agent is very complex and not completely understood but suffiue to say ammonia is released and most probably a complex magnesium sodium silicate combined with cement powder as an interstitial crystalline structure cures to form a lightweight flexible matrix rather than the dense relatively inflexible matrix formed using cement powder alone. The effect of using the agent is illustrated below in relation to tie drawings.

Referring to the drawings and initially to Figures 1 to 4, Figure 1 is a graph illustrating penetration tests with compacted sand, Figure 2 illustrates the same tests with the same sand with 4% cement powder added, Figure 3 illustrates the same tests with the same sand with 4% cement powder and agent added and Figure 4 is as for Figure 3 but with the exterior surface the test block sealed. In each case, the aggregate formed using the cement powder or cement powder and agent is allowed to cure and then soaked to obtain reasonably constant moisture content between test blocks. The blocks are then tested and as can be seen, the stability of the resulting aggregate is increased by at least a factor of 2 when the agent is employed. Figures 5, 6 and 7 illustrate similar tests as those employed on the course grain sand depicted by the graphs of Figures 1 to 4 but in Figures 5 to 7, sandy, silty clay has been used. In this case approximately a 50% improvement results from use of the agent.

Visual comparison between the blocks containing the a aO U...0 sass a L -i 'I 9 cement powder and those containing the agent illustrated reduced shrinkage in those blocks including the agent when compared with the blocks containing in the cement only.

Likewise, there was less evidence of cracking in those test blocks which included the agent.

It will be appreciated from the foregoing that including an agent which promotes increased flexural strength is beneficial particularly in relation to stabilisation of soils although the agent can also be used in relation to conventional concrete constituents. It will be further appreciated that although particular compounds discussed above have been used in the preferred form of the invention, other agents of a similar nature devised by those skilled in the art could be employed to bring about S 15 the same beneficial result. The agents selected and o disclosed above are considered particularly useful because of availability and their inexpensive nature. It should be appreciated however that the present invention is disclosed and defined herein by result rather than the actual particular parts which make up the composition involved.

It is conceivable that agents involving different constituents could be used to bring about the same effect tr but it should be realised that these agents also fall within the scope of the present invention in terms of the 25 result brought about.

Accordingly, whilst the above has been given by way of illustrative example of the present invention, many variations and modifications thereto will be apparent to those skilled in the art without departing from the b~road ambit and scope as set forth in the appended claims.

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Claims

1. A flexibility enhancement agent to improve the flexibility and reduce the tendency of cracking or shrinking in aggregates of f inely divided granular material mixed with cement powder and prepared while wet and allowed to cure, the enhancement agent in use, being mixed with cement powder and the granular material prior to curing and reacting therewith so that af ter curing, the aggregate includes an interstitial relatively flexible matrix bonding the granular material wherein the agent comprises f irst and second parts, said first part comprising a liquid formed from compounds including sodium, calcium, magnesium, potassium, ammonium ion compounds, chlorides, carbonates and water, and said second part comprising a liquid made I '.from compounds including silicates, sodium and water, and wherein the magnesium compound is present in the f irst part in the range of to 6% by weight or about by weight, the ammonium compound in the range of to by weight or about by weight, the calcium compound in the range of a. to 1.5% by weight or about 1.2% by weight, the potassium compound in the range of to by weight or 4 about by weight, the chloride compound in the range of 12% to 21%- by weight or about 16.3%- by weight, the carbonate compound in the range of 4%i to 7% by weight or about 5.6% by weight, water in the range of 52%- to 65%1 by we ight or about 60%6 by weight and the sodium compound making up the remainder.

2. The agent according to claim 1 wherein the agent S S K 'S I includes ammonia available and present in ammonium salts and chlorides present as both volatile and non-volatile chlorine with the ammonium salts and chlorides being present at about 4.6% and about 11.7% by weight respectively.

3. The agent according to any one of claims 1 and 2 wherein the second part functions as an activator solution and has a content of silicate of about 40% by weight as silicon dioxide or other functionally equivalent compounds with balance of water.

4. The agent according to any one of claims 1 to 3 wherein the second part has specific gravity of about 1.12 and a PH of about 9. The agent according to any one of claims 1 to 4 wherein the first part includes compounds selected from the following:- magnesium, calcium and ammonium chlorides or carbonates or ammonium chloride, sodium chloride, magnesium chloride, calcium chloride and sodium carbonate and potassium hydrogen carbonate.

6. The agent according to claim 5 wherein the ammonium chloride comprises sal ammoniac, technical grade powder present in the first part in the range of 5% to 12% by weight or about 7.4% b- weight.

7. The agent accozi.ng to any one of claims 5 and 6 wherein the sodium chloride comprises common salt present in the range of 14% to 20% by weight or about 15.3% by weight. 1 I lillilillmh- 4 4 4 0, (L(T 0

8. The agent according to any one of claims 5 to 7 wherein the calcium chloride suitably comprises flake technical grade present in the range of to 1.5% by weight or about 1.2% by weight

9. The agent according to any one of claims 5 to 8 wherein the magnesium chloride comprises hydrated 6H20 technical grade present in the range of 3% to 6% by weight or about 4% by weight. The agent according to any one of claims 5 to 9 wherein potassium hydrogen carbonate comprises hydrated technical grade present in the range of to 1.2% by weight or about by weight.

11. The agent according to any one of claims 5 to wherein the sodium carbonate suitably comprises anhydrous soda ash or hydrated 10H 2 0 washing soda present in the range of 4% to 7% by weight or about 5.6% by weight.

12. The agent according to any one of claims 5 to 11 wherein preparation of the first part involves mixing the compounds with the sodium carbonate or its equivalent added last.

13. A method of stabilising finely divided granular material including mixing the granular material with cement powder, water and a flexibility enhancement agent according to any one of claims 1 to 12 to form a mixture which, when allowed to cure, results in the finely divided granular material being adhered together to form a stabilised aggregate having greater flexibility than if the agent was omitted. 14

14. A stabilised aggregate of finely divided granular material, cement powder and flexibility enhancement agent according to any on of claims 1 to 12 formed as a reactive mixture and allowed to cure, the stabilised aggregate having a greater flexibility and reduced tendency to cracking and shrinkage than if the agent was omitted. DATED this 29th day of November, 1995. GERHARD SCHILLING By his Patent Attorneys INTELLPRO i1 N 07 \JCA 1 i ABSTRACT There is provided a flexibility enhancement agent, use of the agent and aggregate formed from use of the agent. The aggregates formed are typically in the form of building products, foundations and so forth. The agent is a mixture of selected chemicals which improve the flexural strength of stabilised soil or concrete while at the same time reducing or inhibiting shrinkage. The following table illustrates typical constituents of one preferred form of agent suitable for applying the present invention to stabilisation of soils. Due to the highly reactive nature, the components are typically stored as a two pack in liquid form with the first part typically comprising the following constituents. Constituents by Weight 1 t i i Sodium Chloride

49.0% Ammonium Chloride 22.0% Magnesium Chloride 12.3% Sodium Carbonate 16.6% While the second part comprises:- Sodium Silicate 22% of total L 1 61311*