Concrete admixture

Abstract

The invention provides application of modified sugar as a concrete water reducing agent, wherein the modified sugar is selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and a combination thereof. The modified sugars are used with one or more supplemental active agents comprising pyrosulfite, optionally in combination with gluconates. The modified sugar accounts for 50 wt% or more of the active agent as the water reducing agent.

Description

Technical Field

[0001] The present invention relates to an admixture for concrete. Background Art

[0002] Concrete is a building material formed from a mixture of cement, aggregates (sand and stone), and water. The water used in concrete activates the cement, which acts as a binder (a bonding agent). The aggregates (coarse and fine) in the mixture are bound together by the cement as it sets and cures, forming hardened concrete. Mixtures that use larger aggregates tend to be stronger than those that use finer aggregates. Importantly, the less water you add to a concrete mix, the stronger the mix.

[0003] The cement may typically be a hydraulic cement, such as Portland cement. Portland cement (also known as Ordinary Portland Cement or OPC) may be defined as a cementitious material that meets the requirements of ASTM Cl50 or the requirements of European Standard EN 197-1.

[0004] Portland cement is produced by heating a mixture of raw ingredients, including calcium carbonate, aluminum silicate, silicon dioxide and various iron oxides, to a sintering temperature (usually about 1450 °C) to form clinker. Portland cement clinker is formed by the reaction of calcium oxide with acidic ingredients, primarily producing tricalcium silicate, dicalcium silicate, tricalcium aluminate and the ferrite phase "C4AF" (tetracalcium aluminoferrite).

[0005] The clinker is ground with calcium sulfate (usually in the form of gypsum) in a grinder to provide cement in the form of a fine and uniform powder. Other additives or cement substitutes may be added before or after the grinding process. These include fillers and OPC substitutes, such as calcium carbonate and other minerals, ground granulated blastfurnace slag, natural pozzolans and pulverised fuel ash (PFA). The ingredients that form cement powder (clinker, calcium sulfate and optional additives such as fillers and cement substitutes) can be called a cement composition.

[0006] The strength of concrete is important because it is used to make items that need to have this property. For example, roads, sidewalks, bridges, walls, buildings, and foundations are often made of concrete.

[0007] Concrete admixtures are typically added during the mixing process of cement, aggregate and water to enhance specific properties of fresh or hardened concrete, such as workability, durability or early and / or ultimate strength.

[0008] Concrete admixtures may include one or more water-reducing agents. A water-reducing agent is an additive that reduces the amount of water required for mixing, which can increase the strength of concrete without adversely affecting the workability of the concrete. Concrete admixtures containing one or more water-reducing agents may be called water-reducing concrete admixtures.

[0009] Conventionally, sulfonated melamine resin salts, polycarboxylates, highly condensed naphthalenesulfonic acid formaldehyde salts, lignin sulfonates (lignosulfonates), and the like have been used as water reducing agents.

[0010] It is an object of the present invention to provide an alternative to lignin sulfonate based admixtures whereby the alternative is more cost effective but has a water reducing capacity equal to or greater than that of lignin sulfonate admixtures. Summary of the invention

[0011] The present invention provides, in a first aspect, the use of a modified sugar as a water reducer for concrete, wherein the modified sugar is selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrins, sugar alcohols and combinations thereof, and wherein the modified sugar is used with one or more supplementary active agents comprising a metabisulphite salt, optionally in combination with a gluconate, and wherein the modified sugar comprises 50 wt % or more of the active agent used as the water reducer.

[0012] Importantly, the inventors have discovered that each of the modified sugars described above can be used effectively and successfully in combination with a pyrosulfite, and optionally with a gluconate, to replace the lignin sulfonate material in a water reducing concrete admixture. This is surprising and beneficial.

[0013] Being able to use less lignin sulfonate material has the technical advantage of providing a cheaper water reducing concrete admixture while still achieving good results.

[0014] In general, the modified sugar can be used to partially or completely replace the lignin sulfonate material in the concrete admixture. Therefore, the modified sugar can be referred to as a lignin sulfonate replacer. As mentioned above, lignin sulfonate materials, such as calcium lignin sulfonate or sodium lignin sulfonate, are generally used as water reducers for concrete. When partial replacement is performed, the amount of lignin sulfonate replacer is at least the same as the amount of lignin sulfonate material, preferably more.

[0015] Furthermore, according to the present invention, improved slump retention can be achieved using modified sugars as concrete water reducers.

[0016] Therefore, in one embodiment, the present invention provides the use of a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and combinations thereof as a concrete water reducer, thereby providing concrete with improved slump retention performance. The slump retention performance of the concrete can be improved compared to concrete obtained using a lignin sulfonate material (e.g., calcium lignin sulfonate) as a water reducer.

[0017] In general, the present invention provides new options for reducing the amount of water used for mixing. These new options can increase the strength of concrete without adversely affecting the workability of the concrete. These new options can also improve slump retention performance.

[0018] These new options involve the use of modified sugar materials selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrins, sugar alcohols, and combinations thereof.

[0019] These modified sugar materials are known in the art and are commercially available.

[0020] Glucose syrup is widely available in the market and is made by hydrolysis of starch (e.g. corn, potato, wheat, barley, rice or cassava) to obtain a concentrated solution of glucose, maltose and higher sugars. Acid hydrolysis and / or enzymatic hydrolysis can be used to prepare glucose syrup.

[0021] Standard corn syrup is a syrup that contains glucose, maltose, and higher oligosaccharides. It is made from corn starch and is available in a variety of grades that contain varying amounts of these sugars. Standard corn syrup can then be treated with enzymes to create high maltose corn syrup or high fructose corn syrup.

[0022] In the context of the present invention, high maltose corn syrup has a maltose content of 40 wt% or more, such as 45 wt% to 55 wt% maltose. It is known in the art that maltose levels of 40-55 wt% or more, such as 50-55 wt% or more, or even up to 70-80 wt% or more, can be produced by enzymatic treatment of corn syrup, such as with β-amylase or with a combination of pullulanase and β-amylase.

[0023] In the context of the present invention, high fructose corn syrup has a fructose content of 40 wt% or more, such as 42 wt% to 55 wt% fructose. It is known in the art that fructose levels of 40-55 wt% or more, such as 42-55 wt% or more, can be produced by enzymatic treatment of corn syrup, such as using glucose isomerase or D-xylose isomerase, to convert some of the glucose into fructose.

[0024] In one embodiment, the high fructose corn syrup used in the present invention comprises 40 wt % to 65 wt % fructose, such as 40 wt % to 60 wt % fructose and in particular 40 wt % to 55 wt % fructose. In one embodiment, the high fructose corn syrup used in the present invention comprises 42 wt % or more fructose, such as 42 wt % to 65 wt % fructose, or 42 wt % to 60 wt % fructose, or 42 wt % to 55 wt % fructose.

[0025] The remainder of the high fructose corn syrup, ie, the components other than fructose, may consist essentially of water, glucose, and glucose oligomers.

[0026] In one embodiment, the high maltose corn syrup used in the present invention comprises 40wt% to 80wt% maltose, such as 40wt% to 65wt% maltose and particularly 40wt% to 55wt% maltose. In one embodiment, the high maltose corn syrup used in the present invention comprises 45wt% or more maltose, such as 45wt% to 65wt% maltose, or 45wt% to 55wt% maltose, or 45wt% to 50wt% maltose.

[0027] The high maltose corn syrup used in the present invention can include maltotriose, such as 20wt% or more, or 22wt% or more, or 24wt% or more of maltotriose. In a preferred embodiment, the high maltose corn syrup used in the present invention includes 40wt% or more maltose and 20wt% or more maltotriose, such as 45wt% or more maltose and 24wt% or more maltotriose. It can be that corn syrup includes 40-65wt% maltose and 20-35wt% maltotriose, such as 40-55wt% maltose and 20-30wt% maltotriose, or 45-50wt% maltose and 24-30wt% maltotriose.

[0028] The remainder of the high maltose corn syrup, ie, the components other than maltose and maltotriose, may be composed primarily of water, glucose, and higher sugars.

[0029] Dextrins are low molecular weight polymer carbohydrates formed by the hydrolysis of starch (e.g. potato, corn, rice or wheat). Dextrins are a mixture of polymers in which d-glucose units are linked by α-(1→4) or α-(1→6) glycosidic bonds. Types of dextrins include white dextrin, yellow dextrin, British gum and maltodextrin. White dextrin is made by heating starch at a relatively low temperature in the presence of acid. Yellow dextrin is made by heating starch to a relatively high temperature in the presence of acid. British gum is made by heating starch at a relatively high temperature in the presence of alkali. Maltodextrin is made by partial hydrolysis of starch (e.g. corn or wheat); partial hydrolysis can be done using controlled enzymes or acids. Dextrins are also widely available commercially.

[0030] In one embodiment, the dextrin is white dextrin or yellow dextrin. The dextrin may, for example, be derived from potato starch or corn starch. In one embodiment, dextrin derived from corn starch is preferred.

[0031] Sugar alcohols have the general formula HOCH2(CHOH) n CH2OH, wherein n is 0 or an integer from 1 to 22, preferably from 1 to 10, for example from 2 to 5. In one embodiment, n can be 1, 2, 3 or 4. As can be seen from the formula, 1 -OH group is connected to each carbon in the chain of the sugar alcohol. Many sugar alcohols have n = 3 or 4, i.e., they have chains of five or six carbon atoms because they are derived from pentoses or hexoses. Sugar alcohols are also widely available on the market. Examples of sugar alcohols include ethylene glycol, glycerol, sorbitol, mannitol, xylitol and maltitol. Combinations of two or more sugar alcohols can also be considered. In a preferred embodiment, the sugar alcohol is selected from sorbitol, mannitol, xylitol and combinations thereof. In particular, the sugar alcohol can be sorbitol and / or mannitol.

[0032] Those skilled in the art will appreciate that more than one of these modified sugar materials can be used in combination as long as there are no compatibility issues, but it is not necessary to use more than one. In one embodiment, only one of these modified sugar materials is used. In another embodiment, a combination of two or more of these modified sugar materials is used.

[0033] In one embodiment, glucose syrup and / or high fructose corn syrup and / or high maltose corn syrup are used. In one embodiment, glucose syrup and / or high fructose corn syrup are used.

[0034] In one embodiment, glucose syrup and / or high fructose corn syrup and / or high maltose corn syrup are used as the main modified sugar material, and yellow dextrin is additionally used as a minority modified sugar material. In one embodiment, glucose syrup and / or high fructose corn syrup are used as the main modified sugar material, and yellow dextrin is additionally used as a minority modified sugar material.

[0035] In a second aspect, the present invention further provides a water-reducing concrete admixture, comprising:

[0036] a) a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof; and

[0037] b) one or more supplemental active agents including a pyrosulfite, optionally in combination with a gluconate;

[0038] Wherein, there is no active agent in the admixture whose content (by weight) is greater than that of the modified sugar.

[0039] The advantage of this admixture is that the presence of lignin sulfonate material is not required to achieve good results and the admixture is more cost effective than lignin sulfonate based admixtures.

[0040] Another advantage of using the water-reducing concrete admixture of the second aspect is that the slump retention performance of the concrete can be improved compared to concrete obtained using a lignin sulfonate material (such as calcium lignin sulfonate) as a water-reducing agent.

[0041] The pyrosulfite is suitably an inorganic salt, and is preferably an alkali metal salt or an alkaline earth metal salt, such as a potassium salt, a calcium salt or a sodium salt. In a preferred embodiment, the pyrosulfite is sodium pyrosulfite or calcium pyrosulfite, in particular, sodium metabisulfite (SMBS).

[0042] When gluconate is present, the gluconate is preferably an alkali metal gluconate or an alkaline earth metal gluconate, such as potassium gluconate, calcium gluconate or sodium gluconate. In a preferred embodiment, the gluconate is sodium gluconate.

[0043] In one embodiment, the water reducing concrete admixture comprises both a pyrosulfite and a gluconate, such as sodium pyrosulfite and sodium gluconate. It will be appreciated by those skilled in the art that each of these materials can be provided in the form of a solution or a powder.

[0044] One advantage of the present invention is that modified sugars selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrins, sugar alcohols, and combinations thereof can be effectively and successfully used to partially or completely replace lignin sulfonate materials in water reducing concrete admixtures.

[0045] The admixture may be intended to completely replace lignin sulfonate. In such an embodiment, the water-reducing concrete admixture of the second aspect may, for example, contain no more than 2 wt% of lignin sulfonate material, such as no more than 1 wt% of lignin sulfonate material; and in one embodiment, the admixture does not contain lignin sulfonate material.

[0046] Alternatively, the admixture can be used as a partial substitute for lignin sulfonate. In such an embodiment, the water-reducing concrete admixture of the second aspect comprises:

[0047] a) a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof;

[0048] b) one or more supplemental active agents comprising a pyrosulfite, optionally in combination with a gluconate; and

[0049] c) lignin sulfonate materials;

[0050] Wherein, there is no active agent in the admixture whose content (by weight) is greater than that of the modified sugar.

[0051] In this regard, the modified sugar acts as a lignin sulfonate replacement agent.Thus, the modified sugar should be present in at least the same amount as the lignin sulfonate material, and preferably the modified sugar is present in greater amount than the lignin sulfonate material.

[0052] The advantage of this admixture is that less lignin sulfonate material can be used, thus reducing costs while still achieving good results.

[0053] The lignin sulfonate material may, for example, be selected from sodium lignin sulfonate, calcium lignin sulfonate, magnesium lignin sulfonate, potassium lignin sulfonate, and combinations thereof. In one embodiment, the lignin sulfonate material includes or is calcium lignin sulfonate.

[0054] In the admixture of the present invention, there is no other active agent present in an amount greater than the modified sugar (selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and combinations thereof), i.e., preferably it is the main active agent. In one embodiment, the only component present in the composition in an amount greater than the modified sugar is a solvent (e.g., water), which is of course not considered an active agent.

[0055] Therefore, the water-reducing concrete admixture according to the present invention comprises a modified sugar (selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols and combinations thereof) as the main active agent, which means that the amount of each of the pyrosulfite and any other additional active agent present (such as lignin sulfonate material and / or gluconate) is lower by weight than the amount of the modified sugar selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols and combinations thereof.

[0056] The water-reducing concrete admixture according to the present invention may contain modified sugar (selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and a combination thereof) accounting for at least 50 wt % of the total active agent, preferably greater than 50 wt %. In one embodiment, the modified sugar accounts for 60 wt % or more, or 70 wt % or more, or 75 wt % or more of the active agent in the water-reducing concrete admixture.

[0057] In a third aspect, the present invention also provides a method for producing concrete, the method comprising:

[0058] Cement, aggregate and water are mixed with the water-reducing concrete admixture defined in the second aspect.

[0059] In one embodiment, the water reducing concrete admixture is added at an addition level of 0.1 wt % to 5 wt % (relative to the total dry weight of the binder in the mixture), such as 0.25 wt % to 3 wt %, or 0.5 wt % to 2 wt %.

[0060] The cement (binder) may be a hydraulic cement, such as Portland cement.

[0061] The method can produce a concrete product with improved slump retention properties. DETAILED DESCRIPTION

[0062] In the present invention, modified sugars selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof, are used as water reducing agents for concrete. These materials have been identified as cost-effective alternatives to lignin sulfonate materials, which can replace some or all of the lignin sulfonate materials used in water reducing concrete admixtures.

[0063] Modified sugars selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrins, sugar alcohols, and combinations thereof may be referred to herein as lignin sulfonate replacers.

[0064] Those skilled in the art will appreciate that more than one of these materials may be used in combination as long as there are no compatibility issues, but it is not necessary to use more than one material. In one embodiment, only one of these modified sugar materials is used. In another embodiment, a combination of two or more of these modified sugar materials is used.

[0065] In one embodiment, the modified sugar is glucose syrup, or high maltose corn syrup, or high fructose corn syrup, or white dextrin or yellow dextrin, or a combination thereof. In one embodiment, the modified sugar is glucose syrup or white dextrin or yellow dextrin, or a combination thereof.

[0066] In one embodiment, the dextrin is white dextrin or yellow dextrin derived from potato starch or corn starch. In one embodiment, dextrin derived from corn starch is preferred.

[0067] In one embodiment, the modified sugar is glucose syrup, high maltose corn syrup, high fructose corn syrup, or a combination thereof.

[0068] In one embodiment, the modified sugar is glucose syrup, high fructose corn syrup, or a combination thereof.

[0069] In all aspects of the invention, the lignin sulfonate material which is replaced in whole or in part may in particular be calcium lignin sulfonate. However, it may alternatively or additionally be other lignin sulfonate materials, such as sodium lignin sulfonate or magnesium lignin sulfonate or potassium lignin sulfonate.

[0070] Replace All

[0071] In one embodiment, the lignin sulfonate material is completely replaced. Thus, the water reducing concrete admixture comprises a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof, and contains no lignin sulfonate material (or contains substantially no lignin sulfonate material, e.g., 2 wt % or less).

[0072] The lignin sulfonate replacement agent is used in combination with a supplementary active agent. The supplementary active agent includes a pyrosulfite, optionally in combination with a gluconate.

[0073] There is no active agent in the admixture whose content is greater than that of the modified sugar.

[0074] Water-reducing concrete admixtures can include:

[0075] a) one or more lignin sulfonate replacers selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof; and

[0076] b) A supplemental active agent comprising an alkali metal or alkaline earth metal disulfite; optionally in combination with an alkali metal or alkaline earth metal gluconate.

[0077] In one embodiment, the supplemental active agent is selected from the group consisting of: sodium metabisulfite and calcium metabisulfite, optionally in combination with one or more of potassium gluconate, calcium gluconate, and sodium gluconate.

[0078] In a preferred embodiment, the supplemental active agent is sodium metabisulfite, optionally in combination with sodium gluconate.

[0079] In one embodiment, the supplemental active agent comprises both pyrosulfite and gluconate; in a preferred embodiment, the pyrosulfite and gluconate are included in a weight ratio of 0.5:1 or higher, particularly 0.75:1 or higher, preferably 1:1 or higher, for example, 1.1:1 or higher, or 1.2:1 or higher. The amount of pyrosulfite in the admixture may be at least as much as the amount of gluconate by weight.

[0080] In one embodiment, the amount of pyrosulfite in the admixture may be at least twice, such as three times or more, the amount of gluconate by weight. In another embodiment, the amount of pyrosulfite in the admixture may be about the same as the amount of gluconate by weight.

[0081] The amount of supplemental active agent is the same as or lower than the amount of modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof, by weight.

[0082] Thus, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g. sodium metabisulfite, optionally in combination with sodium gluconate) may be 1:1 to 50:1, such as 1:1 to 40:1, preferably 1:1 to 30:1, such as 1:1 to 25:1 or 1:1 to 20:1 or 1:1 to 15:1.

[0083] In a preferred embodiment, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite, optionally in combination with sodium gluconate) may be 1:1 to 10:1, such as 1:1 to 7:1, preferably 1:1 to 5:1 or 1:1 to 3:1 or 1:1 to 2:1.

[0084] Preferably, the water reducing concrete admixture comprises a modified sugar as a main active agent, wherein the modified sugar is selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and combinations thereof.

[0085] Thus, in one embodiment, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite optionally in combination with sodium gluconate) may be 1.1: 1 to 10: 1, for example 1.1: 1 to 7: 1, preferably 1.1: 1 to 5: 1 or 1.1: 1 to 3: 1 or 1.1: 1 to 2: 1. The weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite optionally in combination with sodium gluconate) may be 1.2: 1 to 10: 1, for example 1.2: 1 to 7: 1, preferably 1.2: 1 to 5: 1 or 1.2: 1 to 3: 1 or 1.2: 1 to 2: 1.

[0086] The water-reducing concrete admixture may optionally further include a solvent. This may be helpful for the convenience of adding the admixture when mixing concrete. In one embodiment, the solvent may be water. When the solvent is present, it may be appropriately present in the water-reducing concrete admixture in an amount up to 95wt%, such as up to 90wt% or up to 85wt%. In one embodiment, when the solvent is present, it may be present in the water-reducing concrete admixture in an amount of 5wt% to 95wt%, such as 10wt% to 90wt% or 15wt% to 85wt%, such as 20wt% to 80wt% or 25wt% to 75wt%.

[0087] In one embodiment, the majority of the water reducing concrete admixture is the lignin sulfonate substitute and the supplementary active agent and the optional solvent (e.g., 60 wt % or more, or 70 wt % or more, or 80 wt % or more, such as 90 wt % or more of the water reducing concrete admixture). In one embodiment, the water reducing concrete admixture may consist primarily of the lignin sulfonate substitute and the supplementary active agent and the optional solvent, or it may consist only of the lignin sulfonate substitute and the supplementary active agent and the optional solvent.

[0088] However, other additives may optionally be present in the water reducing concrete admixture, for example in an amount of 15 wt% or less, such as 10 wt% or less, for example 0.5 wt% to 10 wt% or 1 wt% to 8 wt%. These other additives may be materials known in the art for use in concrete admixtures, such as surfactants (air entraining agents and / or defoamers) and / or amines (known to be used as strength enhancers and / or accelerators) and / or defoamers and / or biocides.

[0089] Amines such as triethanolamine, diethanolamine, dimethylethanolamine, triisopropanolamine and diethanolisopropanolamine, in particular, are known for use in concrete and may optionally be present.

[0090] Specific examples of additives that may be present in the present invention include sodium lauryl ether sulfate, triethanolamine, and triisopropanolamine. Triisobutyl phosphate and formaldehyde are also examples of other additives that may be present in the embodiments.

[0091] Melamine and / or sulfonated melamine resin salts may be optionally included as additives, for example in an amount of 15 wt% or less, such as 10 wt% or less or 5 wt% or less, for example 0.5 wt% to 10 wt% or 1 wt% to 8 wt%. These are water reducers known in the art, but in the present invention their use amounts are lower than conventional amounts.

[0092] In one embodiment, the lignin sulfonate substitute is glucose syrup, or high maltose corn syrup, or high fructose corn syrup, or white dextrin or yellow dextrin, or a combination thereof. In one embodiment, the lignin sulfonate substitute is glucose syrup or white dextrin or yellow dextrin, or a combination thereof. In one embodiment, the lignin sulfonate substitute is glucose syrup or high maltose corn syrup or high fructose corn syrup. In one embodiment, the lignin sulfonate substitute is glucose syrup or high fructose corn syrup.

[0093] Partial replacement

[0094] In one embodiment, the lignin sulfonate material is only partially replaced. Thus, the water reducing concrete admixture comprises (a) a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup or high fructose corn syrup, dextrin, sugar alcohols and combinations thereof, (b) a supplemental active agent including a pyrosulfite, optionally in combination with a gluconate, and (c) a lignin sulfonate material.

[0095] There is no active agent in the admixture in an amount (by weight) greater than that of the modified sugar.

[0096] Therefore, when partial replacement is performed, the lignin sulfonate substitute is present in at least the same amount, preferably in a greater amount (by weight) than the lignin sulfonate material. In a preferred embodiment, the amount of the lignin sulfonate substitute is at least two times (by weight), such as at least three times, that of the lignin sulfonate material.

[0097] The weight ratio of the lignin sulfonate substitute to the lignin sulfonate material may be 1:1 to 50:1, such as 1:1 to 40:1, preferably 1:1 to 30:1, such as 1:1 to 25:1 or 1:1 to 20:1 or 1:1 to 15: 1. In a preferred embodiment, the weight ratio of the lignin sulfonate substitute to the lignin sulfonate material may be 1:1 to 10:1, such as 1:1 to 7:1, preferably 1:1 to 5:1.

[0098] In a preferred embodiment, the weight ratio of the lignin sulfonate replacer to the lignin sulfonate material is 1:1 to 50:1, such as 1:1 to 10:1 or 1:1 to 9:1.

[0099] In a preferred embodiment, the weight ratio of the lignin sulfonate replacer to the lignin sulfonate material is 2:1 to 50:1 or 2:1 to 30:1 or 2:1 to 20:1, such as 2:1 to 10:1 or 2:1 to 9:1.

[0100] In one embodiment, the weight ratio of the lignin sulfonate replacing agent to the lignin sulfonate material is 4:1 to 50:1, such as 4:1 to 10:1 or 4:1 to 9:1.

[0101] In one embodiment, the supplemental active agent is selected from the group consisting of: sodium metabisulfite and calcium metabisulfite, optionally in combination with one or more of potassium gluconate, calcium gluconate, and sodium gluconate.

[0102] In a preferred embodiment, the supplemental active agent is sodium metabisulfite, optionally in combination with sodium gluconate.

[0103] In one embodiment, the supplemental active agent comprises both pyrosulfite and gluconate; in a preferred embodiment, the pyrosulfite and gluconate are included in a weight ratio of 0.5:1 or more, especially 0.75:1 or more, preferably 1:1 or more, for example, 1.1:1 or more, or 1.2:1 or more. It may be beneficial to have at least as much pyrosulfite as gluconate in the admixture by weight.

[0104] In one embodiment, the amount of pyrosulfite in the admixture may be at least two times, such as three times or more, the amount of gluconate by weight. In another embodiment, the amount of pyrosulfite in the admixture may be about the same as the amount of gluconate by weight.

[0105] The amount of supplemental active agent is the same or lower by weight than the amount of modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof.

[0106] Thus, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g. sodium metabisulfite, optionally in combination with sodium gluconate) may be 1:1 to 50:1, such as 1:1 to 40:1, preferably 1:1 to 30:1, such as 1:1 to 25:1 or 1:1 to 20:1 or 1:1 to 15:1.

[0107] In a preferred embodiment, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite, optionally in combination with sodium gluconate) may be 1:1 to 10:1, such as 1:1 to 7:1, preferably 1:1 to 5:1 or 1:1 to 3:1 or 1:1 to 2:1.

[0108] Preferably, the water reducing concrete admixture comprises a modified sugar as a main active agent, the modified sugar being selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohol and combinations thereof.

[0109] Thus, in one embodiment, the weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite optionally in combination with sodium gluconate) may be 1.1: 1 to 10: 1, such as 1.1: 1 to 7: 1, preferably 1.1: 1 to 5: 1 or 1.1: 1 to 3: 1 or 1.1: 1 to 2: 1. The weight ratio of the total amount of lignin sulfonate substitute to the supplementary active agent (e.g., sodium metabisulfite optionally in combination with sodium gluconate) may be 1.2: 1 to 10: 1, such as 1.2: 1 to 7: 1, preferably 1.2: 1 to 5: 1 or 1.2: 1 to 3: 1 or 1.2: 1 to 2: 1.

[0110] The water-reducing concrete admixture may optionally further include a solvent. This may be helpful for the convenience of adding the admixture when mixing concrete. In one embodiment, the solvent may be water. When the solvent is present, it may be appropriately present in the water-reducing concrete admixture in an amount up to 95wt%, such as up to 90wt% or up to 85wt%. In one embodiment, when the solvent is present, it may be present in the water-reducing concrete admixture in an amount of 5wt% to 95wt%, such as 10wt% to 90wt% or 15wt% to 85wt%, such as 20wt% to 80wt% or 25wt% to 75wt%.

[0111] In one embodiment, the majority of the water reducing concrete admixture is the lignin sulfonate substitute and supplementary active agent, as well as the lignin sulfonate material and the optional solvent (e.g., 60 wt % or more, or 70 wt % or more, or 80 wt % or more, such as 90 wt % or more of the water reducing concrete admixture). In one embodiment, the water reducing concrete admixture may consist mainly of the lignin sulfonate substitute and supplementary active agent, as well as the lignin sulfonate material and the optional solvent, or may consist only of the lignin sulfonate substitute and supplementary active agent, as well as the lignin sulfonate material and the optional solvent.

[0112] However, optionally, other additives may be present in the water reducing concrete admixture, for example in an amount of 15 wt% or less, such as 10 wt% or less, for example 0.5 wt% to 10 wt% or 1 wt% to 8 wt%. These other additives may be materials known in the art for use in concrete admixtures, such as surfactants (air entraining agents and / or defoamers) and / or amines (known to be used as strength enhancers and / or accelerators) and / or defoamers and / or biocides.

[0113] Amines such as triethanolamine, diethanolamine, dimethylethanolamine, triisopropanolamine and diethanolisopropanolamine, in particular, are known for use in concrete and may optionally be present.

[0114] Specific examples of additives that may be present in the present invention include sodium lauryl ether sulfate, triethanolamine, and triisopropanolamine. Triisobutyl phosphate and formaldehyde are also examples of other additives that may be present in embodiments.

[0115] Melamine and / or sulfonated melamine resin salts may be optionally included as additives, for example in an amount of 15 wt% or less, such as 10 wt% or less or 5 wt% or less, for example 0.5 wt% to 10 wt% or 1 wt% to 8 wt%. These are water reducers known in the art, but in the present invention their use amounts are lower than conventional amounts.

[0116] In one embodiment, the lignin sulfonate substitute is glucose syrup, or high maltose corn syrup, or high fructose corn syrup, or white dextrin or yellow dextrin, or a combination thereof. In one embodiment, the lignin sulfonate substitute is glucose syrup or white dextrin or yellow dextrin, or a combination thereof. In one embodiment, the lignin sulfonate substitute is glucose syrup or high maltose corn syrup or high fructose corn syrup. In one embodiment, the lignin sulfonate substitute is glucose syrup or high fructose corn syrup.

[0117] Use of admixtures

[0118] The admixture of the present invention may be suitably mixed with cement (binder) at an addition level of 0.1 wt% to 5 wt%, for example 0.25 wt% to 3 wt%, such as 0.5 wt% to 1 wt%.

[0119] The admixture of the invention allows to achieve a good water reduction effect as well as good strength properties.

[0120] The admixture of the present invention can achieve improved slump retention performance. Compared with the concrete obtained by using lignin sulfonate materials (such as calcium lignin sulfonate) as a water reducer, the slump retention performance of the obtained concrete can be improved.

[0121] The invention will now be further illustrated with reference to the following non-limiting working examples.

[0122] Example

[0123] Materials used in the examples were obtained from commercial suppliers.

[0124] Three different concrete mixes were prepared:

[0125] Mixture #1:

[0126]

[0127] Mixture #2:

[0128]

[0129] Mixture #3:

[0130]

[0131] In each case, concrete was mixed using fine aggregate, coarse aggregate, and cement from commercial suppliers.

[0132] The concrete admixture formulation was prepared by mechanically mixing the components listed in Table 1 below at about room temperature (15-35°C). The amounts given are in parts by weight.

[0133]

[0134] Table 1 - Preparations

[0135] High fructose corn syrup is an aqueous solution of sugar with CAS number 8029-43-4.

[0136] Then the prepared admixtures were tested as follows:

[0137] The test concrete was prepared using a pan mixer in which 10 dm 3 volume of the mixture to be tested.

[0138] The tests carried out are in accordance with EN standards, in particular:

[0139] • EN 12350-2: Testing of fresh concrete - Part 2: Slump test

[0140] • EN 12350-6: Testing of fresh concrete - Part 6: Density

[0141] • EN 12350-7: Testing of fresh concrete - Part 7: Air content of fresh concrete - Pressure method

[0142] • EN 12390-3: Testing of hardened concrete - Part 3: Compressive strength of test specimens.

[0143] Each admixture prepared according to Table 1 achieved good results in terms of water reduction, concrete strength and slump reduction.

[0144] In particular, each admixture according to the invention exhibits:

[0145] • Water loss was similar compared to the control group,

[0146] • Similar or better slump retention performance compared to the control group, and

[0147] • Compressive strength was similar or better than that of the control group.

[0148] Each admixture according to the present invention also has the advantage of being cost-effective.

[0149] The detailed results are listed below:

[0150]

[0151] Table 2: Results

[0152] in conclusion

[0153] The admixtures according to the invention are all able to achieve comparable or better water reduction and strength properties than the calcium lignin sulfonate reference.

[0154] Furthermore, the admixtures according to the invention are all able to achieve slump reduction properties comparable to or better than the calcium lignin sulfonate reference.

[0155] Thus, the admixture of the present invention provides a cost-effective alternative to currently used calcium lignin sulfonate based admixtures.

Claims

1. Use of a modified sugar as a concrete water reducer, wherein the modified sugar is selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrins, sugar alcohols and combinations thereof, and wherein the modified sugar is used with a supplementary active agent comprising a pyrosulfite, optionally in combination with a gluconate, and wherein the modified sugar comprises 50 wt % or more of the active agent used as a water reducer.

2. The use according to claim 1, wherein the modified sugar is used to completely replace the lignin sulfonate material in the concrete admixture or partially replace the lignin sulfonate material in the concrete admixture.

3. The use according to claim 1 or 2, wherein the modified sugar is used to improve the slump retention performance of concrete.

4. Use according to any one of claims 1 to 3, wherein the modified sugar comprises more than 50 wt% of the active agent used as a water reducing agent.

5. Use according to any one of claims 1 to 4, wherein the modified sugar is used together with a supplementary active agent comprising pyrosulfite and gluconate.

6. A water-reducing concrete admixture comprising: a) a modified sugar selected from the group consisting of glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, sugar alcohols, and combinations thereof; and b) a supplemental active comprising a metabisulfite, optionally in combination with a gluconate; Wherein, by weight, no active agent is present in the admixture in an amount greater than that of the modified sugar.

7. The admixture of claim 6, wherein the modified sugar accounts for 50 wt% or more, or 60 wt% or more, or 70 wt% or more, or 75 wt% or more of the active agent in the water reducing concrete admixture.

8. The use or admixture of any one of claims 1 to 7, wherein the supplementary active agent is selected from: an alkali metal or alkaline earth metal pyrosulfite, optionally in combination with an alkali metal or alkaline earth metal gluconate.

9. The use or admixture of claim 8, wherein the supplementary active agent is selected from the group consisting of sodium metabisulfite and calcium metabisulfite, optionally in combination with potassium gluconate, calcium gluconate or sodium gluconate.

10. The use or admixture of claim 9, wherein the supplementary active agent is sodium metabisulfite, optionally in combination with sodium gluconate.

11. The use or admixture of any one of claims 1 to 10, wherein the supplementary active agent comprises pyrosulfite and gluconate.

12. The use or admixture of claim 11, wherein the pyrosulfite and the gluconate are contained in a weight ratio of pyrosulfite:gluconate of 0.5:1 or higher, or 1:1 or higher, or 1.1:1 or higher, or 1.2:1 or higher.

13. The use or admixture of any one of claims 1-12, wherein the weight ratio of the modified sugar to the supplementary active agent is 1:1 to 50:1, or 1:1 to 25:1, or 1:1 to 15:1, or 1:1 to 5:

1.

14. The use or admixture of any one of claims 1-13, wherein the weight ratio of the modified sugar to the supplementary active agent is from 1.1:1 to 10:1, or from 1.1:1 to 7:1, or from 1.1:1 to 5:

1.

15. The use or admixture of any one of claims 1 to 14, wherein no lignin sulfonate material is present.

16. The use or admixture of any one of claims 1 to 14, wherein a lignin sulfonate material is present, wherein the amount of the modifying sugar is at least the same as the amount of the lignin sulfonate material, and preferably the amount of the modifying sugar is greater than the amount of the lignin sulfonate material.

17. The use or admixture of claim 16, wherein the weight ratio of the modified sugar to the lignin sulfonate material is (a) 1:1 to 50:1, or (b) 1:1 to 10:1, or (c) 1:1 to 9:1, or (d) 2:1 to 50:1, or (e) 2:1 to 10:1, or (f) 2:1 to 9:

1.

18. The use or admixture of claim 16 or 17, wherein the lignin sulfonate material is selected from the group consisting of sodium lignin sulfonate, calcium lignin sulfonate, magnesium lignin sulfonate, potassium lignin sulfonate and combinations thereof.

19. The admixture of any one of claims 6-18, wherein the admixture further comprises a solvent.

20. The admixture of claim 19, wherein the solvent comprises water.

21. The admixture of claim 19 or 20, wherein the admixture comprises the solvent in an amount of 5 wt% to 95 wt%, or 15 wt% to 85 wt%, or 25 wt% to 75 wt%.

22. The use or admixture of any one of the preceding claims, wherein the modified sugar is selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, dextrin, a sucrose having the molecular formula HOCH2(CHOH) n Sugar alcohols of CH2OH, and combinations thereof, wherein n is zero or an integer from 1 to 22.

23. The use or admixture of claim 22, wherein the modified sugar is selected from glucose syrup, high maltose corn syrup, high fructose corn syrup, white dextrin, yellow dextrin, HOCH2(CHOH) n Sugar alcohols of CH2OH, and combinations thereof, wherein n is zero or an integer from 1 to 10.

24. The use or admixture of claim 23, wherein the modified sugar is selected from (a) glucose syrup, high maltose corn syrup, high fructose corn syrup, and combinations thereof; or (b) glucose syrup, high fructose corn syrup, and combinations thereof.

25. A method for producing concrete, the method comprising: Cement, aggregate and water are mixed with the water-reducing concrete admixture according to any one of claims 6 to 24.

26. The method of claim 25, wherein the water reducing concrete admixture is added at an addition level of 0.1 wt% to 5 wt%.

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