WO2013123181A1

WO2013123181A1 - Concrete compositions and methods of making

Info

Publication number: WO2013123181A1
Application number: PCT/US2013/026130
Authority: WO
Inventors: Dwayne DILLINGHAM; Dave BRASSARD
Original assignee: Gobasalt Llc
Priority date: 2012-02-14
Filing date: 2013-02-14
Publication date: 2013-08-22

Abstract

A method for preparing a concrete composition having improved properties is provided, the method including the steps of combining portland cement and one or more aggregates to form a cement pre-mix; combining a boron-containing compound, a silicon-containing compound other than sand, a surfactant, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition. In alternative embodiments, an organic acid and/or an encapsulated acid may be employed.

Description

CONCRETE COMPOSITIONS AND METHODS OF MAKING

TECHNICAL FIELD

[01] Embodiments of the present invention relate to construction materials. More specifically, embodiments of the invention relate to concrete compositions with improved properties.

BACKGROUND OF THE INVENTION

[02] Conventional concrete is universally utilized for road surfaces, in building flooring in skyscrapers and in piping and drainage assemblies among others. Typical concrete displays porosity to water, salts and vapors. These shorten the useful life of the product via limited stability in freeze thaw situations causing spallation, chloride ion permeation causing rebar failure and violent spallation from high temperature exposure in fires. Thermal spallation will occur with direct contact of flame. Concrete that is exposed to high temperatures is typically replaced as it loses strength and reliability. Irreparable damage is typically imparted in concrete exposed to temperatures in excess of 400 oF. Violent spallation can also occur when concrete is exposed to high heat or fire as low as 1700 oF for 5 minutes. These problems create difficulties in the field, achieving long term performance in assemblies as well as safety issues.

[03] In addition, typical concrete displays a significant exotherm during the cure cycle. These increases in temperature can result in expansion of the concrete, thermal cracking and slab curl. External cooling and a delayed step- wise application are typical approaches to offsetting the exotherm problem. This often creates waste of loads and labor. In warm, tropical climates the exotherm creates even greater problems requiring pouring at night. Fast drying creates handling issues, which include: finishing uniformity, uniformity of packing, honeycombing and shrinkage with cracking.

[04] Typical concrete also requires a lengthy cure cycle. Many concrete mixtures require up to 28 days to display full strength. These long cure cycles delay projects and create higher project costs. These problems create significant difficulties in the field during lengthy application times, structural quality issues and inefficiency creating budget over-runs. [05] Typical concrete has a short working time. After the typical 1.5 to 2 hrs. are exceeded, the concrete has to be dumped as it will start curing. These short cycles create many handling issues.

[06] Those skilled in the art routinely utilize many admixtures into concrete. Most are for very specific functions as follows: Silicas are utilized to increase strength. Both micron and nanosized silicas in powder and liquid forms are used to increase strength. Certain soaps are utilized to incorporate air into the uncured mixture. This air incorporation creates a higher volume and lower viscosity mandated by ACL It is mandated by law in cold climates and in pumping and transporting the uncured mixtures. Calcium carbonates, glycols and other additives as added to raise the freezing point this is essential in pouring concrete in very cold or below freezing conditions. Plasticization through lignosulphates will increase workability and reduce water consumption. Superplasticization is accomplished with sulphonated naphthalene and melamine formaldehydes. Both plasticization and superplasticization increase workability by reducing water up to 40%. Retardation and acceleration of cure speeds is also accomplished with various other admixtures. Viscosity reducing and corrosion inhibiting admixtures are known. All of the above admixtures offer some benefit. Secondary waterproofing/sealing operations have been performed on cured concrete mixtures with short term, limited success. However, improved compositions and method with improved capability to seal out liquids and/or water vapor, a reduced-exotherm capability, and/or enabling a more rapid cure, are needed.

SUMMARY OF THE INVENTION

[07] One or more embodiments of the present invention provides a method for preparing a concrete composition, the method comprising the steps of combining portland cement and one or more aggregates to form a cement pre-mix; combining a boron-containing compound, a silicon-containing compound other than sand, a surfactant, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition. [08] One or more embodiments of the present invention provides a method for preparing a concrete composition, the method comprising the steps of combining portland cement and one or more aggregates to form a cement pre-mix; combining at least one acid, a silicon-containing compound other than sand, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition.

[09] One or more embodiments of the present invention further provides a method for preparing a concrete composition, the method comprising the steps of combining portland cement and one or more aggregates to form a cement pre-mix; combining at least one organic acid, a silicon-containing compound other than sand, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, an encapsulated acid, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition.

[10] One or more embodiments of the present invention provides a concrete composition prepared by combining portland cement and one or more aggregates to form a cement pre-mix; combining a boron-containing compound, a silicon-containing compound other than sand, a surfactant, and water to form an additive pre-mix; mixing the cement pre- mix, the additive pre-mix, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition.

[11] One or more embodiments of the present invention provides a concrete composition comprising portland cement; one or more aggregates selected from the group consisting of sand, crushed stone, and gravel; one or more surfactants selected from the group consisting of amphoteric, anionic, cationic, and nonionic surfactants, with the proviso that the compostion comprises less than 0.1 wt. % of any air entrainment surfactant; a boron- containing compound selected from the group consisting of boron nitride, borax, boric acid, and sodium salts of boric acid; and a silicon-containing compound other than sand selected from the group consisting of silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica, fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica, organosilane-treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane- treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

[12] One or more embodiments of the invention further provide a concrete composition comprising portland cement; one or more aggregates selected from the group consisting of sand, crushed stone, and gravel; one or more acids selected from the group consisting of organic acids; a silicon-containing compound other than sand, selected from the group consisting of silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica, fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica, organosilane-treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers); and optionally one or more encapsulated acids that are encapsulated in a water-soluble shell..

BRIEF DESCRIPTION OF THE DRAWINGS

[13] Fig. 1 is a graphical representation of temperature (°F) versus time for Example E.

[14] Fig. 2 is a graphical representation of temperature versus time for Example F.

[15] Fig. 3 is a graphical representation of temperature versus time for Example B.

[16] Fig. 4 is a graphical representation of temperature versus time for Example D.

[17] Figs. 5-18 are sequential pictorial representations of testing according to ASTM E-119.

DETAILED DESCRIPTION OF THE INVENTION

[18] Embodiments of the compositions of the present invention utilize a unique combination of key additives to create portland concrete mixes having very unique properties. In one or more embodiments, these unique properties are accomplished via a more thorough hydration of the concrete. [19] In one or more embodiments, the concrete compositions include portland cement, one or more aggregates, one or more surfactants, a boron-containing compound, and a silicon- containing compound other than sand.

[20] In one or more embodiments, the portland cement is defined by ASTM C 150. In one or more embodiments, the portland cement includes calcium oxide, silicon dioxide, aluminum oxide, ferric oxide, and sulfate. In one or more embodiments, the portland cement includes calcium oxide, CaO, 61-67%, silicon dioxide, Si0₂, 19-23%, aluminum oxide, A1₂0₃, 2.5-6%, ferric oxide, Fe₂0₃, 0-6%, sulfate 1.5-4.5%, wherein all percentages are expressed in mass percent.

[21] The amount of portland cement in the concrete composition is not particularly limited. In one or more embodiments, the amount of portland cement is from about 5 to about 25 wt. %, based upon the total weight of the concrete composition. In other embodiments, the amount of portland cement is from about 7 to about 20 wt. %, in other embodiments, from about 9 to about 18 wt. %, based upon the total weight of the concrete composition.

[22] Examples of aggregates include, without limitation, sand, gravel, and crushed stone. In one or more embodiments, the aggregates include sand and crushed stone. Mixtures of stone dust and larger crushed stone may be employed. Examples of crushed stone include class 57 stone. In one or more embodiments, the average diameter of the class 57 stone is from about 0.75 inches to about 1 inch.

[23] The amount of aggregates in the concrete composition is not particularly limited. In one or more embodiments, the amount of crushed stone is from about 30 to about 70 wt. %, in other embodiments from about 35 to about 68 wt. %, in other embodiments, from about 38 to about 65 wt. %, based upon the total weight of the concrete composition. In one or more embodiments, the amount of sand is from about 30 to about 70 wt. %, in other embodiments from about 35 to about 68 wt. %, in other embodiments, from about 38 to about 65 wt. %, based upon the total weight of the concrete composition.

[24] Examples of surfactants include, without limitation amphoteric, anionic, cationic and nonionic surfactants. In one or more embodiments, the surfactant is selected from anionic surfactants, with the proviso that the anionic surfactant is not an air entrainment surfactant. While some anionic surfactants have previously been employed at high pH (8-14) for air entrainment, air entrainment surfactants are not preferred in the present invention, because direct fire contact will cause spallation when the concrete contains micro bubbles. Therefore, in one or more embodiments, the concrete compositions of the present invention contain less than about 0.1 wt. % of air entrainment surfactants, in other embodiments, less than about 0.05 wt. %, and in other embodiments, less than about 0.01 wt. % of air entrainment surfactants, based upon the total weight of the concrete composition. In one or more embodiments, the concrete composition is devoid of air entrainment surfactants.

[25] In one or more embodiments, the amount of surfactant (non-air entrainment surfactant) in the concrete composition is from about 0.01 to about 0.10 wt. %, in other embodiments, from about 0.02 to about 0.08 wt. %, based upon the total weight of the concrete composition.

[26] Examples of boron-containing compounds include salts, acids and esters. More specific examples of boron-containing compounds include boron nitride, borax, boric acid, sodium salts of boric acid, and the like.

[27] In one or more embodiments, the amount of boron-containing compound in the concrete composition is from about 0.01 to about 0.20 wt. %, in other embodiments, from about 0.02 to about 0.18 wt. %, in other embodiments, from about 0.05 to about 0.15 wt. %, based upon the total weight of the concrete composition.

[28] Examples of silicon-containing compounds other than sand include, without limitation, silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane-treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

[29] In one or more embodiments, siloxanes are employed. In one or more embodiments, the siloxanes may lower surface tension of the composition. Examples of siloxanes include silsequioxanes, POSS, trimethyl and silanol terminated polydimethylsiloxanes, and hydride-terminated siloxane copolymers.

[30] In one or more embodiments, the amount of silicon-containing compound other than sand in the concrete composition is from about 0.01 to about 0.50 wt. %, in other embodiments, from about 0.02 to about 0.45 wt. %, in other embodiments, from about 0.05 to about 0.41 wt. %, in other embodiments, from about 0.08 to about 0.39 wt. %, based upon the total weight of the concrete composition.

[31] In one or more embodiments, the concrete compositions include portland cement, one or more aggregates, one or more acids, and a silicon-containing compound other than sand. The portland cement, one or more aggregates, and silicon-containing compound other than sand may be as described above. Optionally, a surfactant may also be present, as described above.

[32] In one or more embodiments, the acid is an organic acid. In one or more embodiments, the organic acid is a carboxylic acid. In one or more embodiments, the carboxylic acid may be selected from the group consisting of acetic acid, formic acid, citric acid, oxalic acid, benzoic acid, propionic acid, stearic acid, malic acid, malonic acid, butyric acid, and the like.

[33] In one or more embodiments, the amount of organic acid in the concrete composition is from about 0.001 to about 0.25 wt. %, in other embodiments, from about 0.01 to about 0.20 wt. %, in other embodiments, from about 0.1 to about 0.18 wt. %, based upon the total weight of the concrete composition.

[34] In one or more embodiments, the concrete composition includes two or more acids. In one or more embodiments, the two or more acids include a mineral acid and an organic acid. In one or more embodiments, at least one of the acids is encapsulated. Examples of encapsulated acids include acetic acid, phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, formic acid, acetic acid, sulfamic acids, citric acid, glycolic acid, maleic acid, and fumeric acid.

[35] Examples of encapsulation shell material include semi-permeable membrane material such as, but not limited to, partially to fully hydrogenated vegetable oil, such as tristearin, latex, gelatins, carageenans, polyethylene, polypropylene, polyisobutylene, a copolymer of vinyl chloride and vinylidene chloride, a copolymer of vinylidene chloride and an ester of an unsaturated carboxylic acid or a copolymer of ethylene and an unsaturated carboxylic acid.

[36] In one or more embodiments, the thickness of the shell is from about 0.1 millimeter (mm) to about 2.0 mm. Advantageously, the thickness of the shell and the type of shell material may be selected such that the shell dissolves or ruptures within a certain time period, thus allowing the acid to mix with the other ingredients and initiate cure of the cement.

[37] In one or more embodiments, the amount of encapsulated acid in the concrete composition is from about 0.1 to about 0.5 wt. %, in other embodiments, from about 0.11 to about 0.45 wt. %, based upon the total weight of the concrete composition.

[38] Optional ingredients may also be present, such as additives known in the art of concrete, with the proviso that they do not deleteriously affect the properties of the concrete. Advantageously, additives that have typically been used in conventional concrete compositions are not necessary for the compositions of the present invention, and can be limited or absent. For example, in one or more embodiments, the compositions of the present invention contain less than about 0.5 wt. % of any super plasticizers, in other embodiments less than about 0.2 wt. %, in other embodiments less than about 0.1 wt. % super plasticizers, based upon the total weight of the concrete composition. In one or more embodiments, the compositions are devoid of super plasticizers.

[39] In one or more embodiments, the compositions of the present invention contain less than about 0.5 wt. % of any accelerators, in other embodiments less than about 0.2 wt. %, in other embodiments less than about 0.1 wt. % accelerators, based upon the total weight of the concrete composition. In one or more embodiments, the compositions are devoid of accelerators.

[40] In one or more embodiments, the compositions of the present invention contain less than about 0.5 wt. % of any high pH soaps, in other embodiments less than about 0.2 wt. %, in other embodiments less than about 0.1 wt. % high pH soaps, based upon the total weight of the concrete composition. In one or more embodiments, the compositions are devoid of high pH soaps.

[41] As is known in the art, water is added during the process of mixing the concrete ingredients, in order to hydrate the cement. The amount of water may vary, so long as enough water is added to saturate and hydrate the portland cement. In one or more embodiments, the amount of water is from about 0.2 to about 0.8, in other embodiments, from about 0.25 to about 0.6 parts by weight, per hundred parts by weight of the composition. [42] An exemplary mixture of a standard Class C concrete, without the additives of the present invention, would include about 564 pound of standard type 1 portland cement, about 1800 pounds of class 57 stone, about 1200 pounds of sand, and about 25 gallons of water. Into this standard Class C mix the key additives are utilized at levels less than about 2 percent and greater than about 0.1 % by weight.

[43] The present invention further provides a method of preparing a concrete composition, the method comprising the steps of combining ingredients that include portland cement, one or more aggregates, one or more surfactants, a boron-containing compound, a silicon-containing compound other than sand, and water, to form a mixture. In one or more embodiments, the mixture is substantially homogeneous. That is, the aggregate is substantially well-distributed throughout the mixture. In one or more embodiments, the mixture may be characterized as having a liquid paste consistency.

[44] The present invention further provides a method of preparing a concrete composition, the method comprising the steps of combining ingredients that include portland cement, one or more aggregates, a silicon-containing compound other than sand, one or more acids, and water, to form a mixture. In one or more embodiments, the mixture is substantially homogeneous. That is, the aggregate is substantially well-distributed throughout the mixture. In one or more embodiments, the mixture may be characterized as having a liquid paste consistency.

[45] In one or more embodiments, the aggregates may be pre-blended prior to adding them to the cement. In one or more embodiments, the portland cement and aggregates are mixed with stirring or rotation, prior to adding the surfactants, boron-containing compound, and silicon-containing compound other than sand. One or more of the ingredients may be pre- mixed with water, and added to the mixture as a slurry or solution.

[46] In one or more embodiments, the method further comprises the steps of placing the mixture, compacting the mixture, and curing the mixture.

[47] Advantageously, the composition of the shell of the microencapsulated acid, as well as the shell thickness, can be selected to activate the cure of the mixutre at any desired cure time. As the shell dissolves, at the desired cure time, the mixture rapidly turns solid. Thus, the methods of the present invention enable a cure-on-demand capability, while maintaining a relatively low hydration exotherm. [48] In one or more embodiments of the present invention, the concrete compositions contain less free water within the cured concrete composition, when compared to standard concrete compositions, where standard concrete compositions are concrete compositions that contain the same amount of portland cement, aggregates, and water, but do not contain the additives taught herein. In one or more embodiments, the cured concrete compositions of the present invention are substantially non-porous. Advantageously, the non-porosity results in reduced spallation from both freezing and exposure to high temperatures. In addition, the sealed concrete composite material will not allow surface water, salts, chloride containing liquids or other liquids to permeate into the cured concrete composite. This sealed structure will enable a long service-life product by reducing premature wear from spallation and in addition minimize metallic rebar corrosion.

[49] In one or more embodiments, concrete compositions of the present invention results in a concrete composite product that is more durable, and offers a non-exotherm capability unique in concrete type products. That is, embodiments of the present invention exhibit a lower hydration exotherm than standard concrete compositions. Embodiments of the methods of the present invention provide a cure-on-demand curing technology, wherein the user may select a desired open time prior to a rapid on-set of cure.

[50] In order to demonstrate the practice of the present invention, the following examples have been prepared and tested. The examples should not, however, be viewed as limiting the scope of the invention. The claims will serve to define the invention.

EXAMPLES

[51] Example A was prepared by combining the following ingredients, in a concrete mixer, at approximately room temperature (65 oF), in the order shown, to form a mixture having the following proportions:

14.95 % standard Portland Cement

31.80 % sand

47.71 % Class 57 stone

5.51 % water

0.01 to 0.1 % boron-containing compound

0.01 to 0.1 % wet or dry silica [52] Example B was prepared by combining the following ingredients, in a concrete mixer, at approximately room temperature (65 oF), in the order shown, to form a mixture having the following proportions:

14.95 % standard Portland Cement

31.80 % sand

47.71 % Class 57 stone

5.51 % water

0.01 to 0.1 % organic acid

0.01 to 0.1 % wet or dry silica

[53] Example C was prepared by combining the following ingredients, in a concrete mixer, at approximately room temperature (65 oF), in the order shown, to form a mixture having the following proportions:

14.95 % standard Portland Cement

31.80 % sand

47.71 % Class 57 stone

5.51 % water

0.01 to 0.1 % wet or dry silica

0.001 to 0.1 % mineral acid, encapsulated

0.001 to 0.1 % organic acid

[54] Comparative Control Example D was prepared by combining the following ingredients, in a concrete mixer, at approximately room temperature (65 oF), in the order shown, to form a mixture having the following proportions:

14.95 % standard Portland Cement

31.81 % sand

47.73 % Class 57 stone

5.51 % water [55] Water absorption for Example A compared to Example D was measured as follows. The samples were weighed, and then totally immersed in room temperature water. At intervals of 1 hour, 6 hours, and 12 hours, the samples were removed from the water and towel dried, and then weighed. The measured weight gain for Example A, and the percent weight gain based upon the total original weight, is summarized in Table 1 below. It can be seen that the compositions of the present invention absorb water at a significantly slower rate.

Table 1

Example

A Weight % gain at start 242.2 g.

1 hr. 242.3 g. 0.04%

6 hrs. 242.6 g. 0.16%

12 hrs. 242.6 g. 0.16%

24 hrs. 242.7 g. 0.20%

Water absorption of control vs. time Example

D Weight % gain at start 243.7 g.

1 hr. 255.9 g. 5.00%

6 hrs. 272.5 g. 11.80%

12 hrs. 288.6 g. 18.40%

24 hrs. 292.4 g. 20.00% [56] Thermal spallation for Example A compared to Example D was measured using a direct flame, according to ASTM method El 19. Results are shown below. Table 2

[57] Freeze thaw testing was performed, according to ASTM method C666 and results after 300 cycles is shown below.

Table 3

Spallation/percent

Example A damaged

A-l 3%

A-2 3%

A-3 1%

Average 2.30%

Example D

Control D- 1 15%

Control D- 2 17%

Control D-

[58] Cure speed for Example B and Example D was measured by break force vs. time, according to ASTM method C39. Results are summarized below. Table 4

Break force vs. time

Example B Example D

7 days 1350 PSI 2800 PSI

14 days 2000 PSI 3200 PSI

21 days 3100 PSI 3700 PSI

28 days 4500 PSI 4000 PSI

[59] The exotherm during curing was measured for Examples B and D according to ASTM method CI 074-11. Results of one test run are summarized below.

Table 5

Exotherm during

curing in degrees F

Example

B Example D

0 hrs. 65F 65 F

12 hrs. 68F 11 IF

24 hrs. 68F 130F

48 hrs. 65F 130F

72hrs. 83F 130F

[60] Example E was prepared according to the procedure described above for Example B, except that the amount of acid was slightly lower, although still within the stated range. The exotherm during curing for Example E is shown graphically in Fig. 1.

[61] Example F was prepared according to the procedure described above for Example B, except that the amount of acid was slightly lower, although still within the stated range, and slightly higher than the amount of acid in Example E. The exotherm during curing for Example F is shown graphically in Fig. 2.

[62] Example B was re-run, and the exotherm during curing is shown graphically in Fig. 3. Example D (control) was re-run, and the exotherm during curing is shown graphically in Fig. 4. [63] Cure speed was measured according to ASTM C 1074- 11. Results are summarized below for Example C-l, C-2, C-3 and Control Example D, wherein C-l, C-2, and C-3 were each prepared according to the procedure described above for Example C, and differ only in the thickness of the shell that was used to encapsulate the mineral acid. The thickness of the shell employed in C-3 was greater than the thickness of the shell employed in C-2, which was greater than the thickness of the shell employed in C-l, all of which were within the range disclosed as suitable herein above.

Table 6 Working time of concrete

Example D 1.5 hrs. only

Example C-l 3 hrs.

Example C-2 4 hrs.

Example C-3 5 hrs.

[64] Example G was prepared as follows. Portland cement (300 grams) and concrete sand (900 grams) was combined. From about 0.01 to about 0.1 wt. % wet or dry silica was mixed with 36 grams of water. From about 0.001 to about 0.1 wt. % of a mineral acid was added to the water mixture, and then the water mixture was added to the cement/sand mixture. The sample was cubed and tested according to ASTM method CI 09, and the results are shown below.

[65] Example H was prepared according to the procedure described above for Example G, except that a slightly lower amount of acid was employed, albeit still within the stated range. Example I was prepared according to the procedure described above for Example G, except that the amount of acid was slightly lower than the amount of acid in Example H, albeit still within the stated range.

[66] Example J differs from Example G in that the acid was not pre-mixed with water and silica, but was added straight to the mixture of the cement and aggregate, and also in that the amount of acid was greater than the stated range of 0.001 to 0.1 wt. %.

[67] The control sample was prepared as follows. Portland cement (300 grams) and concrete sand (900 grams) was combined, and mixed with 36 grams of water. The sample was cubed and tested according to ASTM method CI 09. [68] Examples G, H, I, J and the control were tested according to ASTM method CI 09, and the results are summarized below.

TABLE 7

Failure

ID Length Width Depth Load Strength Mode

Example

G 2 2 2 7650 1915 2

Example

G 2 2 2 8490 2120 2

Example

H 2 2 2 6480 1620 2

Example

H 2 2 2 7780 1945 2

Example

I 2 2 2 9460 2365 2

Control 2 2 2 6390 1600 2

Control 2 2 2 7420 1855 2

Example

J 2 2 2 6770 1690 2

[69] As shown in Fig. 5-18, concrete compositions prepared according to the present invention, in this case a composition according to Example A, do not exhibit any spoliation when tested according to ASTM E-119. Fig. 5 shows the pre-test condition, with beams in place. Fig. 6 shows the columns and small cylinder in place. Fig. 7 shows the slab being put into place. Fig. 8 shows insulation around the beams and bricks closing the opening between the beams. Fig. 9 shows the gas on. Fig. 10 shows a time of 1 :04. Fig. 11 shows the T/C wire going into the end of the beam. Fig. 12 shows a time of 2:00 and no change. Fig. 13 shows a time of 3:00 and no change. Fig. 14 shows a time of 4:00 and no change. Fig. 15 shows the removal of the slabe after the test, and the exposed side. Figs. 16 and 17 show the columns and beams intact after the test. Fig. 18 shows the columsn and cylinder after the test.

[70] The following two tables show the temperature data for the ASTM E-119 test.

Table 8

Furnace Temperature Degrees in °F

20 79 862 852 851 853 856 1462

30 81 1044 936 1028 1012 1005 1550

40 83 1096 983 1059 1092 1060 1613

50 84 1080 1026 1056 1115 1069 1661

60 83 1094 1043 1068 1138 1086 1700

1 :10 86 1135 1040 1104 1131 1103 1735

1:20 87 1142 1097 1128 1159 1132 1765

1:30 85 1160 1142 1136 1243 1170 1792

1:40 86 1174 1160 1156 1264 1188 1815

1:50 85 1194 1191 1184 1276 1211 1835

2:00 88 1215 1215 1194 1304 1232 1850

2:10 87 1232 1236 1209 1314 1248 1862

2:20 87 1250 1248 1222 1326 1262 1875

2:30 87 1252 1265 1234 1371 1281 1888

2:40 92 1250 1266 1236 1340 1273 1900

2:50 91 1320 1305 1293 1414 1333 1912

3:00 90 1294 1344 1303 1448 1347 1925

3:10 91 1314 1381 1324 1450 1367 1338

3:20 91 1359 1400 1351 1490 1400 1950

3:30 89 1408 1438 1390 1530 1441 1962

3:40 92 1386 1476 1394 1547 1451 1975

3:50 91 1414 1482 1418 1578 1473 1988

4:00 93 1435 1491 1433 1581 1485 2000

Table 9

Degrees in °F

130 81 563 678 555 388 535 223 259

140 82 617 711 586 400 373 242 269

150 82 666 746 614 413 396 274 279

160 83 708 778 640 433 418 255 289

170 86 750 813 665 451 439 266 299

180 83 793 847 691 469 461 272 306

190 85 824 881 721 488 484 280 311

200 84 861 911 750 507 507 288 318

210 85 897 946 799 527 531 303 333

220 86 931 981 808 547 555 302 345

230 87 963 1008 835 * 579 313 362

240 85 990 1034 859 599 315 371

* T/C misread at 230 minutes

[71] Thus it can be seen that, in one or more embodiments, the following is provided. 1 - A concrete mixture that allows longer travel times due to a larger percentage of hydration of Portland. This results in a concrete product with less shrinkage and cracking. 2 - A concrete mixture that is easier to finish due to its slower curing, due to hydration. 3 - A concrete mixture that upon curing displays a fireproof, non-spalling surface when held at direct flame and temperatures as high as 5000 oF. Typically trapped water becomes steam and explodes violently releasing projectiles of concrete. 4 - A concrete product that displays a very low surface porosity and low absorption of exposed liquids. Additionally claimed is a reduced rate of chloride ion penetration due to internal pore sealing from the technology. 5 - A concrete product that cures faster and stronger than typical concrete, ie. 7 days @ 4660 PSI vs. 7 days to 3660 PSI for 564 pounds portland. 6 - Stronger bond to and suspension of stone in mix vs. typical settling out. Enhanced thixotropy through hydrogen bonding enables a uniform suspension of reinforcing solids. 7 - Increased flexural strength of 700 vs. 600 PSI and reduced slab curl from a fuller reacted concrete mix and less shrinkage. 8 - A concrete product with enhanced freeze thaw potential via internal pore sealing of the concrete. These sealed pores disallow water egress and the resultant expansion and spallation from freezing. 9 - A concrete mixture that reduces the production of hydroxides, which are corrosive to steel, metal rebar and application equipment. 10 - A safer to use concrete mixture that through a reduced pH results in less skin irritation and chemical burns. 11 - A safer to use concrete that minimizes skin burns through a greatly reduced or eliminated exotherm. 12 — A green concrete product that through less hydroxides has less impact to the environment via less basic water run-off.

[72] In one or more embodiments, the following is provided. 1 - A concrete mixture containing key additives that displays, upon curing, a sealed, non-porous composite that has reduced surface porosity and low absorption of exposed liquids. This is unlike standard, unsealed concrete, which absorbs water. 2 - A concrete mixture containing key additives that upon curing displays a fireproof, non-spalling surface when held at direct flame at temperatures as low as 1,800 oF. This in unlike standard concrete, which rapidly releases trapped water becoming steam, and explodes violently releasing projectiles of concrete. 3 - A concrete mixture containing key additives that offers, through reduced surface permeability to liquids, a reduced rate of liquid absorption and chloride ion penetration due to internal pore sealing from the technology. This reduced chloride content should directly translate to enhanced rebar service life. 4 -A concrete mixture containing key additives to result in a more thorough hydration of the cement mixture. 5 - A concrete mixture containing key additives to result in a concrete product with reduced free water content. This reduced free water content will result in reduced spallation from freeze thaw conditions. 6 - A concrete mixture containing key additives that results in a product with enhanced freeze thaw potential via internal pore sealing of the concrete. These sealed pores disallow surface water egress and the resultant expansion and spallation from freezing as typically found in cold climates. 7 - A concrete mixture containing key additives that upon curing results in a sealed concrete composite material. Concrete compositions of the present invention require 14 days to fully stop liquid transmission, and don't require a secondary coating operation to be fully sealed. This is unlike standard concrete, which takes 28 days to fully cure and then it requires a secondary operation to be coated to seal-out liquids. 8 - A concrete mixture containing key additives that creates, upon curing, a concrete product that cures stronger than standard concrete. Standard concrete requires 28 days to attain the same 4000 PSI break strength. 9 - A concrete mixture containing key additives that, during curing, displays a minimal exotherm (from less than 8 to about 36 °F). Concrete compositions of the present invention are unlike standard concrete, which displays a significant exotherm of greater than 75 oF from time of placement. 10 -Due to the low exotherm or even no exotherm, concrete compositions of the present invention offer a reduced slab curl and little or no thermal cracking in the cured concrete. Standard concrete experiences thermal expansion and contraction resulting in dimensional changes. 11 - The methods of the present invention enable a cure on demand capability, by utilizing microencapsulated acidic activators with a water soluble shell. 12 - Varying rates of cure are included in the methods of the present invention, and can be accomplished via varying microencapsulation material shell composition and thickness. 13 - Acidic activators within the microencapsulated beads can contain organic acids, which upon reacting with the concrete produce seed crystal formation, resulting in rapid cure with a low heat of hydration.

[73] In one or more embodiments, the following is provided. 1 - A concrete mixture containing key additives that during curing displays a less than about 8 oF exotherm at 24 hours, as compared to standard concrete, which display a significant exotherm of more than about 75 to 100 oF from placement temperature. 2 - A concrete mixture containing key additives that creates upon curing a concrete product that is denser and stronger than standard concrete, and that during curing displays a minimal exotherm of less than about 8 oF. 3 - A method of preparing a cured concrete composition wherein no exotherm is produced during curing, or wherein a minimal exotherm is produced during curing. 4 - A cured concrete composition having reduced slab curl, as compared to standard concrete wherein thermal expansion and contraction results in dimensional changes. 5 - A cured concrete composition having less shrinkage during cure, due to the absence of a substantial exotherm during curing, as compared to standard concrete wherein thermal expansion and contraction result in greater shrinkage.

[74] Various modifications and alterations that do not depart from the scope and spirit of this invention will become apparent to those skilled in the art. This invention is not to be duly limited to the illustrative embodiments set forth herein.

Claims

CLAIMS What is claimed:

1. A method for preparing a concrete composition, the method comprising the steps of:

combining portland cement and one or more aggregates to form a cement pre- mix;

combining a boron-containing compound, a silicon-containing compound other than sand, a surfactant, and water to form an additive pre-mix;

mixing the cement pre-mix, the additive pre-mix, and water to form a saturated cement mixture;

placing the saturated cement mixture in a form;

compacting the saturated cement mixture; and

curing the saturated cement mixture to form a concrete composition.

2. The method of claim 1, wherein the one or more aggregates include sand and crushed stone.

3. The method of claim 1, wherein the boron-containing compound is selected from the group consisting of boron nitride, borax, boric acid, sodium salts of boric acid, and mixtures thereof.

4. The method of claim 1, wherein the silicon-containing compound other than sand is selected from silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane- treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

5. The method of claim 1, wherein the amount of silicon-containing compound other than sand is from about 0.01 to about 0.5 wt.%, based upon the total weight of the concrete composition.

6. The method of claim 1, wherein the amount of boron-containing compound is from about 0.01 to about 0.20 wt. %, based upon the total weight of the concrete composition.

7. The method of claim 1, wherein the surfactant is an anionic surfactant, and is not an air entrainment surfactant.

8. The method of claim 1, wherein the concrete composition exhibits no spallation when tested according to ASTM El 19, when compared to the same concrete composition but not containing any of the additive pre-mix.

9. The method of claim 1, wherein the concrete composition exhibits less spallation when tested according to ASTM C666, when compared to the same concrete composition but not containing any of the additive pre-mix.

10. The method of claim 1, wherein the concrete composition exhibits less water absorption when tested according to ASTM C666, when compared to the same concrete composition but not containing any of the additive pre-mix.

11. A method for preparing a concrete composition, the method comprising the steps of:

combining portland cement and one or more aggregates to form a cement pre- mix;

combining at least one acid, a silicon-containing compound other than sand, and water to form an additive pre-mix;

placing the saturated cement mixture in a form;

compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition.

12. The method of claim 11 wherein the one or more aggregates include sand and crushed stone.

13. The method of claim 11 wherein the acid is selected from the group consisting of acetic acid, formic acid, citric acid, oxalic acid, benzoic acid, propionic acid, stearic acid, malic acid, malonic acid, butyric acid, and mixtures thereof.

14. The method of claim 11 wherein the silicon-containing compound other than sand is selected from silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane- treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

15. The method of claim 11, wherein the amount of silicon-containing compound other than sand is from about 0.01 to about 0.5 wt. %, based upon the total weight of the concrete composition.

16. The method of claim 11 wherein the amount of acid is from about 0.001 to about 0.25 wt. %, based upon the total weight of the concrete composition.

17. A method for preparing a concrete composition, the method comprising the steps of:

combining portland cement and one or more aggregates to form a cement pre- mix;

combining at least one organic acid, a silicon-containing compound other than sand, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, an encapsulated acid, and water to form a saturated cement mixture;

placing the saturated cement mixture in a form;

compacting the saturated cement mixture; and

curing the saturated cement mixture to form a concrete composition.

18. The method of claim 17, wherein the one or more aggregates include sand and crushed stone.

19. The method of claim 17, wherein the organic acid is selected from the group consisting of acetic acid, formic acid, citric acid, oxalic acid, benzoic acid, propionic acid, stearic acid, malic acid, malonic acid, butyric acid, and mixtures thereof.

20. The method of claim 17, wherein the silicon-containing compound other than sand is selected from silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane- treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

21. The method of claim 17, wherein the amount of silicon-containing compound other than sand is from about 0.01 to about 0.50 wt. %, based upon the total weight of the concrete composition.

22. The method of claim 17, wherein the amount of organic acid is from about 0.001 to about 0.25 wt. %, based upon the total weight of the concrete composition.

23. The method of claim 17, wherein the amount of encapsulated acid is from about 0.1 to about 0.5 wt. %, based upon the total weight of the concrete composition.

24. A concrete composition prepared by combining portland cement and one or more aggregates to form a cement pre-mix; combining a boron-containing compound, a silicon- containing compound other than sand, a surfactant, and water to form an additive pre-mix; mixing the cement pre-mix, the additive pre-mix, and water to form a saturated cement mixture; placing the saturated cement mixture in a form; compacting the saturated cement mixture; and curing the saturated cement mixture to form a concrete composition.

25. A concrete composition comprising:

portland cement;

one or more aggregates selected from the group consisting of sand, crushed stone, and gravel;

one or more surfactants selected from the group consisting of amphoteric, anionic, cationic, and nonionic surfactants, with the proviso that the compostion comprises less than 0.1 wt. % of any air entrainment surfactant;

a boron-containing compound selected from the group consisting of boron nitride, borax, boric acid, and sodium salts of boric acid; and

a silicon-containing compound other than sand, selected from the group consisting of silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane- treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers).

26. A concrete composition comprising:

portland cement;

one or more acids selected from the group consisting of organic acids; a silicon-containing compound other than sand, selected from the group consisting of silicates, siloxanes, polyhedral oligomeric silsesquioxane (POSS), silsequioxanes, silicone MQ resins, silanes, silicone polymers, silicone copolymers, and wet or dry silica. Examples of silicas include fused or ground quartz (from about 5 microns to about 100 microns in particle size), colloidal silica, precipitated silica and organosilane-treated precipitated silica (primary particle size from about 13 to about 100 nanometers), fumed silica and organosilane-treated fumed silica (particle size from about 9 nanometers to about 300 nanometers); and

optionally one or more encapsulated acids that are encapsulated in a water-soluble shell.