A kind of preparation method of starch base hydration heat of cement controlled materialTechnical field
The invention belongs to construction material concrete admixture field, and in particular to a kind of starch base hydration heat of cement regulates and controls materialThe preparation method of material.
Background technology
The hydration reaction of cement is an exothermic reaction, and the concrete that cement plus water and other aggregate mixs are made is being pouredIn rear condensation, hardening process, the substantial amounts of heat of hydration can be produced.Because concrete is the non-conductor of heat, and volume is larger, becauseThis heat of hydration is gathered in inside concrete and is difficult diverging, steeply rises internal temperature.Simultaneously as concrete surface radiating compared withIt hurry up, generate larger internal-external temperature difference, cause inside and outside thermal expansion and contraction degree different, and then tension is produced in concrete surface.When tension exceedes concrete ultimate tensile strength, thermal cracking will be produced, this crack majority occurs in pouringLater stage, intensity and durability to concrete produce harmful effect.In order to slow down concentration heat release of the concrete at the initial stage that pours, justNeed to regulate and control hydrated reaction of cement process, especially the regulation and control to aquation accelerated period rate of heat release, and then reach diminutionThe effect of temperature difference between inside and outside concrete.
Patent EP1233008A1 discloses a kind of expansion agent material containing dextrin, solubility is mixed into swelling agent smallIn after 70% commercially available dextrin, the material shows certain heat of hydration inhibition.Patent CN102674738A is disclosedA kind of Multifunctional anti-crack additive and preparation method thereof, it is 20%-80%'s that its component, which includes calcium oxide expansive clinker, solubility,Commercially available industrial dextrin and flyash, the anti-crack additive can reduce concrete heat release temperature rise.But not yet explicitly refer in above-mentioned patentGo out commercially available dextrin species, dextrin made from different material, Different Preparation has larger difference in nature, so as to cause realityIt is uncertain with property.Simultaneously as dextrin is unmodified dextrin, therefore its heat of hydration regulating effect still has room for promotion.
Patent CN104628296A discloses a kind of composite modified heat of hydration controlled material, by starch first with acid catalyst,Crosslinking agent reacts, and product is made with alkenyl succinic acid anhydride reactant again.Patent CN104098288A discloses a kind of concrete hydratingHeat suppresses material, is made by carrying out epoxy pronane modification to enzymolysis dextrin.Above-mentioned patent results show that starch or dextrin are through changingProperty processing after the regulating effect of hydration heat of cement has been strengthened, but above-mentioned patent complicated, the reaction condition that is modified preparation processIt is whard to control, and the reaction time is longer.
In summary, because raw material sources are extensive, preparation technology is different, commercially available dextrin is made to there is larger difference in natureIt is different, therefore need to be defined the preparation technology of dextrin before modification, it is ensured that its performance is stable.By entering to starch or dextrinRow is modified to be conducive to improving its heat of hydration regulating effect, but current modified technique is more complicated, and the reaction time is long.
The content of the invention
It is undesirable for the regulating effect of existing hydration heat of cement controlled material, or material preparation process complexity, during reactionBetween it is long the problems such as, the invention discloses a kind of preparation method of simple efficient starch base hydration heat of cement controlled material.
Applicant tests through numerous studies and found, Regulation Mechanism of the starch base hydration heat of cement controlled material to hydrated cementitiousSuction-operated of the hydroxyl to cement granules mainly in starch or dextrin molecule.Utilize mixed dibasic acid acid anhydride and enzymatic starchDouble esterification reaction occurs for the hydroxyl in molecule, can slow down rate of dissolution of the enzymatic starch under strong alkali environment, and then slow down hydroxylIn the rate of adsorption of cement particle surface, so as to regulate and control the progress of hydration heat reaction.
The invention provides a kind of preparation method of starch base hydration heat of cement controlled material, by mixed dibasic acid acid anhydride and enzymeSolve starch to be well mixed, be placed in progress solid phase reaction in microwave reactor and be made, specifically include following steps：
(1) preparation of enzymatic starch：Starch is added water the starch milk for being modulated into that mass concentration is 30-50%；Adjusted with sulfuric acidSave pH to 5-6 after add mixing starch enzyme, be placed in double-frequency ultrasound reactor and reacted, controlling reaction temperature be 45-55 DEG C,Ultrasonic power is that 400-700W, supersonic frequency are respectively 20-40kHz and 50-80kHz, and the reaction time is 0.5-1.5h, and electricity consumptionDynamic agitator is stirred continuously, and speed of agitator is 100-250r/min；After reaction terminates, pH to less than 3 is adjusted to go out enzyme with sulfuric acid30min, then pH is adjusted into neutrality with saturation sodium hydroxide, is filtered, and solid content is placed in dry to water content in 50 DEG C of baking ovens is6-8%, crushes, sieves, screen size is less than 200 mesh；
(2) preparation of heat of hydration controlled material：Mixed dibasic acid acid anhydride is well mixed with the enzymatic starch, microwave is placed inSolid phase reaction is carried out in reactor, it is 500-900W to control microwave power, the reaction time is 3-8min, then size-reduced, screening, productionThing screen size is less than 100 mesh, produces the starch base hydration heat of cement controlled material；
The mass ratio of the mixed dibasic acid acid anhydride and enzymatic starch is (0.3-0.6)：1.
Starch described in step (1) is that wheaten starch, cornstarch, farina, tapioca or waxy corn form sedimentOne kind in powder.
Mixing starch enzyme described in step (1) is isoamylase and carbohydrase, and the enzyme concentration of isoamylase is 20-50U/gStarch, the enzyme concentration of carbohydrase is 15-30U/g starch.
Mixed dibasic acid acid anhydride described in step (2) is any two in succinic anhydride, glutaric anhydride or phthalic anhydrideKind.
Present invention also offers application of the above-mentioned heat of hydration controlled material in concrete, its volume is concrete gelling materialExpect the 0.3-0.8% of consumption.
Beneficial effect of the present invention：
1. the present invention uses double-frequency ultrasound auxiliary enzymes hydrolysis starch, make whole reaction system evenly, not only increase enzymeHydrolysis efficiency, while ensure that the property more stable homogeneous of hydrolysate, this is to finally giving aquation prepared by the present inventionHot controlled material is very crucial.
2. mixed dibasic acid acid anhydride carries out solid phase reaction with enzymatic starch using microwave method in the present invention, technique is simple, significantlyThe reaction time is shortened, reaction efficiency is improved, while avoiding the use of solvent, harm of the discarded object to environment is reduced.
3. heat of hydration controlled material prepared by the inventive method can effectively slow down the heat release speed of aquation accelerated period and deceleration periodRate, reduction hydration heat speed peak value more than 80%, and have substantially no effect on concrete middle and later periods intensity.With conventional set retarder significantlyDelay aquation induction period different, heat of hydration controlled material produced by the present invention is not obvious to the retarding action of aquation induction period.
Brief description of the drawings
Fig. 1 is influence of the embodiment 2 when volume is 0.3% to hydrated cementitious rate of heat release.
Embodiment
Present disclosure is further described with reference to embodiment, but present disclosure is not limited to realityApply the scope of example statement.
Without special instruction in the embodiment of the present invention, the cement used is conch P.O.42.5 cement.Hydrated cementitious is putThe measure of hot speed is carried out using TAM-AIR isothermal calorimeters (TA Instruments), and the water-cement ratio of test cement paste is0.4, test temperature is 20 DEG C.Compared with being not added with the net slurry of starch base hydration heat of cement controlled material, starch base hydrated cementitiousThe performance of hot controlled material is better, then the range of decrease of hydration heat speed peak value is bigger.
In the embodiment of the present invention, test the concrete mix that uses for：Cement 288kg/m3, flyash 72kg/m3, water195kg/m3, sand 775kg/m3, stone 1165/m3.Sand is the middle sand that modulus of fineness is 2.6, and stone is that particle diameter is 5-20mmThe rubble of continuous grading.
Adiabatic temperature rise of concrete uses Boyuan Science ＆ Technology Development Co. Ltd., Zhoushan City BY-ATC/JR type adiabatic temperature rise instruments,It is 15 DEG C to test initial temperature.
The setting time of concrete and strength test method are with reference to GB 8076-2008《Concrete admixture》Carry out.
Embodiment 1
The preparation of enzymatic starch：30g wheaten starches are added water the starch milk for being modulated into that concentration is 30wt%, are adjusted with sulfuric acidPH to 5.5, adds mixing starch enzyme, the wherein enzyme concentration of isoamylase is 20U/g starch, and the enzyme concentration of carbohydrase is 20U/gStarch.Above-mentioned starch milk is placed in double-frequency ultrasound reactor and reacted, regulation reaction temperature is 50 DEG C, double-frequency ultrasound powerFor 400W, double-frequency ultrasound frequency is respectively 30kHz and 50kHz, and is stirred continuously using electric mixer, and rotating speed is 100r/After min, reaction 1.5h, adjust pH to less than 3 to go out enzyme 30min with sulfuric acid, then pH be adjusted to neutrality with saturation sodium hydroxide, filter,It is 6-8% to water content that solid content, which is placed in 50 DEG C of baking ovens dry, crushes, crosses 200 mesh sieves.
The preparation of starch base hydration heat of cement controlled material：By enzymatic starch produced above and succinic anhydride, glutaric acidAcid anhydride is well mixed, and the mass ratio of wherein succinic anhydride, glutaric anhydride and enzymatic starch is respectively 0.25：1 and 0.15：1.It is placed in micro-Solid phase reaction is carried out in ripple reactor, regulation microwave power is 500W, and the reaction time is 8min.Product is crushed, 100 mesh are crossedSieve, produces starch base hydration heat of cement controlled material of the present invention.
Embodiment 2
The preparation of enzymatic starch：30g cornstarch is added water the starch milk for being modulated into that concentration is 50wt%, is adjusted with sulfuric acidPH to 6, adds mixing starch enzyme, the wherein enzyme concentration of isoamylase is 40U/g starch, and the enzyme concentration of carbohydrase forms sediment for 30U/gPowder.Above-mentioned starch milk is placed in double-frequency ultrasound reactor and reacted, regulation reaction temperature is 55 DEG C, and double-frequency ultrasound power is600W, double-frequency ultrasound frequency is respectively 30kHz and 60kHz, and is stirred continuously using electric mixer, and rotating speed is 200r/min,React after 1h, adjust pH to less than 3 to go out enzyme 30min with sulfuric acid, then pH is adjusted to neutrality with saturation sodium hydroxide, filter, by solidIt is 6-8% that thing, which is placed in 50 DEG C of baking ovens and dried to water content, crushes, crosses 200 mesh sieves.
The preparation of starch base hydration heat of cement controlled material：By enzymatic starch produced above and succinic anhydride, adjacent benzene twoFormic anhydride is well mixed, and the mass ratio of wherein succinic anhydride, phthalic anhydride and enzymatic starch is respectively 0.15：1 and 0.45：1.It is placed in microwave reactor and carries out solid phase reaction, regulation microwave power is 900W, and the reaction time is 8min.Product is crushed,100 mesh sieves are crossed, starch base hydration heat of cement controlled material of the present invention is produced.
Embodiment 3
The preparation of enzymatic starch：30g waxy corn starch is added water the starch milk for being modulated into that concentration is 40wt%, uses sulfuric acidPH to 6 is adjusted, mixing starch enzyme is added, the wherein enzyme concentration of isoamylase is 50U/g starch, and the enzyme concentration of carbohydrase is 30U/G starch.Above-mentioned starch milk is placed in double-frequency ultrasound reactor and reacted, regulation reaction temperature is 50 DEG C, double-frequency ultrasound work(Rate is 700W, and double-frequency ultrasound frequency is respectively 40kHz and 80kHz, and is stirred continuously using electric mixer, and rotating speed is 250r/After min, reaction 1.5h, adjust pH to less than 3 to go out enzyme 30min with sulfuric acid, then pH be adjusted to neutrality with saturation sodium hydroxide, filter,It is 6-8% to water content that solid content, which is placed in 50 DEG C of baking ovens dry, crushes, crosses 200 mesh sieves.
The preparation of starch base hydration heat of cement controlled material：By enzymatic starch produced above and glutaric anhydride, adjacent benzene twoFormic anhydride is well mixed, and the mass ratio of wherein glutaric anhydride, phthalic anhydride and enzymatic starch is respectively 0.3：1 and 0.25：1.It is placed in microwave reactor and carries out solid phase reaction, regulation microwave power is 700W, and the reaction time is 7min.Product is crushed,100 mesh sieves are crossed, starch base hydration heat of cement controlled material of the present invention is produced.
Embodiment 4
The preparation of enzymatic starch：30g farinas are added water the starch milk for being modulated into that concentration is 40wt%, are adjusted with sulfuric acidPH to 5 is saved, mixing starch enzyme is added, the wherein enzyme concentration of isoamylase is 40U/g starch, and the enzyme concentration of carbohydrase is 15U/gStarch.Above-mentioned starch milk is placed in double-frequency ultrasound reactor and reacted, regulation reaction temperature is 45 DEG C, double-frequency ultrasound powerFor 500W, double-frequency ultrasound frequency is respectively 20kHz and 50kHz, and is stirred continuously using electric mixer, and rotating speed is 200r/After min, reaction 0.5h, adjust pH to less than 3 to go out enzyme 30min with sulfuric acid, then pH be adjusted to neutrality with saturation sodium hydroxide, filter,It is 6-8% to water content that solid content, which is placed in 50 DEG C of baking ovens dry, crushes, crosses 200 mesh sieves.
The preparation of starch base hydration heat of cement controlled material：By enzymatic starch produced above and succinic anhydride, adjacent benzene twoFormic anhydride is well mixed, and the mass ratio of wherein succinic anhydride, phthalic anhydride and enzymatic starch is respectively 0.4：1 and 0.1：1.It is placed in microwave reactor and carries out solid phase reaction, regulation microwave power is 700W, and the reaction time is 6min.Product is crushed, mistake100 mesh sieves, produce starch base hydration heat of cement controlled material of the present invention.
Embodiment 5
The preparation of enzymatic starch：30g tapiocas are added water the starch milk for being modulated into that concentration is 30wt%, are adjusted with sulfuric acidPH to 5.5, adds mixing starch enzyme, the wherein enzyme concentration of isoamylase is 30U/g starch, and the enzyme concentration of carbohydrase is 25U/gStarch.Above-mentioned starch milk is placed in double-frequency ultrasound reactor and reacted, regulation reaction temperature is 55 DEG C, double-frequency ultrasound powerFor 700W, double-frequency ultrasound frequency is respectively 20kHz and 80kHz, and is stirred continuously using electric mixer, and rotating speed is 150r/After min, reaction 1h, adjust pH to less than 3 to go out enzyme 30min with sulfuric acid, then pH is adjusted to neutrality with saturation sodium hydroxide, filter, willIt is 6-8% that solid content, which is placed in 50 DEG C of baking ovens and dried to water content, crushes, crosses 200 mesh sieves.
The preparation of starch base hydration heat of cement controlled material：By enzymatic starch produced above and succinic anhydride, glutaric acidAcid anhydride is well mixed, and the mass ratio of wherein succinic anhydride, glutaric anhydride and enzymatic starch is respectively 0.1：1 and 0.2：1.It is placed in microwaveSolid phase reaction is carried out in reactor, regulation microwave power is 800W, and the reaction time is 3min.Product is crushed, 100 mesh sieves are crossed,Produce starch base hydration heat of cement controlled material of the present invention.
Benchmark
Without the cement paste or concrete of any additive.
Comparative example 1
Succinic anhydride.
Comparative example 2
Glutaric anhydride.
Comparative example 3
Phthalic anhydride.
Comparative example 4
Enzymatic starch made from embodiment 1.
Comparative example 5
Enzymatic starch made from embodiment 2.
Comparative example 6
Enzymatic starch made from embodiment 3.
Comparative example 7
Enzymatic starch made from embodiment 4.
Comparative example 8
Enzymatic starch made from embodiment 5.
Comparative example 9
The preparation of enzymatic starch：Method be the same as Example 2.
The preparation of starch base hydration heat of cement controlled material：Enzymatic starch produced above is mixed with phthalic anhydrideUniformly, the mass ratio of phthalic anhydride and enzymatic starch is 0.6：1.It is placed in microwave reactor and carries out solid phase reaction, adjustsMicrowave power is 900W, and the reaction time is 8min.Product is crushed, 100 mesh sieves is crossed, produces.
Comparative example 10
The preparation of enzymatic starch：Method be the same as Example 2.
The preparation of starch base hydration heat of cement controlled material：Method, will be with the embodiment 2 in patent CN101863994AUpper obtained enzymatic starch, succinic anhydride, phthalic anhydride are well mixed with 60g dimethyl sulfoxide (DMSO)s, wherein succinic anhydride, neighbourThe mass ratio of phthalate anhydride and enzymatic starch is respectively 0.15：1 and 0.45：1,98% concentrated sulfuric acid 0.5mL is added dropwise, backflow is installedCondensing unit, is placed in microwave reactor, and regulation microwave power is 900W, and the reaction time is 8min, takes out cooling, filters, willSolid content, which is placed in 50 DEG C of baking ovens, to be dried to constant weight, is crushed, is crossed 100 mesh sieves, produce.
1 to 10 couple of hydrated cementitious peak heat release rates of testing example 1 to 5 and comparative example and the influence of concrete performance,It the results are shown in Table 1.
1 to 10 couple of hydrated cementitious peak heat release rates of the embodiment 1 to 5 of table 1 and comparative example and the influence of concrete performance
As can be seen from Table 1, inhibition of the enzymatic starch after modified to hydrated cementitious peak heat release rates substantially increasesBy force, while the influence to concrete coagulating time and middle and later periods intensity reduces.Before concrete coagulating time is not obviously prolongedPut, increase volume, inhibition of the starch base hydration heat of cement controlled material to hydration heat speed peak value can be improved.With makingCompared with single dibasic acid anhydride, using starch base hydration heat of cement controlled material made from mixed dibasic acid acid anhydride to hydration heat speedThe inhibition of rate peak value is more preferable.Compared with carrying out microwave reaction using solvent method, present invention process is simply efficient, without " three wastes "Produce.Starch base hydration heat of cement controlled material highest produced by the present invention can effectively reduce hydration heat speed peak value85.2%, and concrete middle and later periods intensity is not influenceed substantially.
Influence of the testing example 2 to Adiabatic temperature rise of concrete, the results are shown in Table 2.
Influence of the embodiment 2 of table 2 to Adiabatic temperature rise of concrete
As can be seen from Table 2, add after embodiment 2, the adiabatic temperature rise climbing speed of concrete substantially slows down, and shows goodGood heat of hydration regulating effect.