CN109626951A - A kind of magnesium phosphate cement - Google Patents
A kind of magnesium phosphate cement Download PDFInfo
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- CN109626951A CN109626951A CN201910031164.3A CN201910031164A CN109626951A CN 109626951 A CN109626951 A CN 109626951A CN 201910031164 A CN201910031164 A CN 201910031164A CN 109626951 A CN109626951 A CN 109626951A
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
- C04B28/34—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing cold phosphate binders
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B2111/00—Mortars, concrete or artificial stone or mixtures to prepare them, characterised by specific function, property or use
- C04B2111/72—Repairing or restoring existing buildings or building materials
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Abstract
The present invention provides a kind of magnesium phosphate cements comprising: magnesia, potassium dihydrogen phosphate, sand, borax, flyash and water.The cement magnesium phosphorus ratio and water-cement ratio are optimal, are suitable for reparation construction operation.
Description
Technical field
The invention belongs to technical field of concrete, are related to a kind of magnesium phosphate cement.
Background technique
In history of the concrete as more than 160 years of construction material, concrete has many excellent compared with other materials
Point, reinforced concrete structure are still most commonly used construction material in the world.But due to carbonization, steel bar corrosion etc. is asked
Topic, concrete structure durability reduce.In highway engineering, the volume of traffic is continuously increased, and locomotive load-carrying increases, and is caused sternly to highway
The destruction of weight.Natural calamity takes place frequently, and the research of patching material is increasingly taken seriously.
Magnesium phosphate cement has unique advantage in repairing work, of interest by domestic and international many scholars.Magnesium phosphate water
Mud is one kind at normal temperature plus water, generation Acid-Base neutralization reaction between magnesia and soluble phosphate are formed with centainly viscous
The novel air-setting inorganic coagulation material of knotting strength.
Compared with magnesium phosphate cement and ordinary portland cement common in engineering etc., setting time is had the advantage that
It is short；Early strength development is very fast, and intensity is higher；Wearability is good, and shrinking percentage is low；Linking new and old concrete intensity is high；Low temperature
Hardening capacity is good；Fireproof high-temperature resistant performance is good.
The influence factor of magnesium phosphate cement mainly has: raw material, magnesium phosphorus ratio (M/P), water-cement ratio (W/B), retarder and blending
Expect type and its volume etc..The application of puzzlement magnesium phosphate cement is main the reason is that optimal proportion can not determine at present, although
Domestic and foreign scholars have done a large amount of experimental study, but for its optimal material matching still none final conclusion, can not cut
Real science instructs engineer application.
Summary of the invention
Based on technical problem present in existing magnesium phosphate cement, the present invention proposes a kind of magnesium phosphate water of optimal proportion
Mud makes it suitable for reparation construction operation.
In order to solve the above technical problems, the application provides a kind of magnesium phosphate cement comprising: magnesia, potassium dihydrogen phosphate,
Sand, borax, flyash and water.
Wherein, the magnesium phosphorus molar ratio of cement be preferably 7.0-8.5, further preferably 7.0.
Wherein, water-cement ratio is preferably 0.18-0.21, and further preferably 0.21.
Wherein, borax volume is the 5%-10% of magnesia quality.
Wherein, the mass percent of coal ash instead magnesium phosphate cement is 15%, substitutes the quality meaning of magnesium phosphate cement
For, the quality of two kinds of substances of the magnesia for being to maintain magnesium phosphorus ratio and potassium dihydrogen phosphate of coal ash instead and.
The present invention also provides the preparation methods of above-mentioned magnesium phosphate cement comprising:
The first step, weighs raw material according to calculating to match, and mortar stirring is added in magnesia, potassium dihydrogen phosphate, borax and sand
Pot, stirring at low speed 30s is uniformly mixed siccative, and then plus water stirs at low speed 30s blends raw material tentatively with water, last high-speed stirring
Mixing 90s is sufficiently mixed magnesium phosphate cement mortar uniformly；
Second step, the magnesium phosphate cement mortar after being sufficiently stirred is poured into die trial rapidly, while being placed to shake table
On, make the abundant vibration compacting of magnesium phosphate cement mortar, be subsequently placed in natural curing in air, conserves 3h demoulding；
Third step, after demoulding, by test block natural curing in air.
Beneficial technical effect
The present invention proposes a kind of magnesium phosphate cement of optimal proportion, makes it suitable for reparation construction operation.
Detailed description of the invention
When Fig. 1 water-cement ratio is 0.18, magnesium phosphorus compares the influence of setting time；
When Fig. 2 water-cement ratio is 0.21, magnesium phosphorus compares the influence of setting time；
When Fig. 3 water-cement ratio is 0.18, magnesium phosphorus compares the influence of mobility；
When Fig. 4 water-cement ratio is 0.21, magnesium phosphorus compares the influence of mobility；
When Fig. 5 water-cement ratio is 0.18, magnesium phosphorus compares the influence of compression strength；
When Fig. 6 water-cement ratio is 0.21, magnesium phosphorus compares the influence of compression strength；
Fig. 7 water-cement ratio be 0.21 when, compression strength with magnesium phosphorus ratio variation；
When Fig. 8 magnesium phosphorus ratio is 7.0, influence of the water-cement ratio to setting time；
When Fig. 9 magnesium phosphorus ratio is 8.5, influence of the water-cement ratio to setting time；
When Figure 10 magnesium phosphorus ratio is 7.0, influence of the water-cement ratio to mobility；
When Figure 11 magnesium phosphorus ratio is 8.5, influence of the water-cement ratio to mobility；
When Figure 12 magnesium phosphorus ratio is 5.5, influence of the water-cement ratio to compression strength；
When Figure 13 magnesium phosphorus ratio is 7.0, influence of the water-cement ratio to compression strength；
When Figure 14 magnesium phosphorus ratio is 8.5, influence of the water-cement ratio to setting time；
Figure 15 magnesium phosphorus is than the influence with water-cement ratio to flexural strength；
When Figure 16 water-cement ratio is 0.18, influence of the introducing of flyash to magnesium phosphate cement setting time and mobility；
When Figure 17 water-cement ratio is 0.21, influence of the introducing of flyash to magnesium phosphate cement setting time and mobility；
When Figure 18 water-cement ratio is 0.18, influence of the doping quantity of fly ash to magnesium phosphate cement compression strength；
When Figure 19 water-cement ratio is 0.21, influence of the doping quantity of fly ash to magnesium phosphate cement compression strength；
Influence of Figure 20 doping quantity of fly ash to magnesium phosphate cement flexural strength；
When Figure 21 water-cement ratio is 0.18, doping quantity of fly ash is to resistance to compression after magnesium phosphate cement 28d compression strength and its immersion 7d
The influence of intensity；
When Figure 22 water-cement ratio is 0.18, influence of the mobility to coefficient of softing after flyash doping；
When Figure 23 water-cement ratio is 0.21, doping quantity of fly ash is to resistance to compression after magnesium phosphate cement 28d compression strength and its immersion 7d
The influence of intensity；
When Figure 24 water-cement ratio is 0.21, influence of the mobility to coefficient of softing after flyash doping；
Figure 25 water-cement ratio is 0.24, and magnesium phosphorus compares the influence of coefficient of softing；
Influence of the flyash mixed dosage of Figure 26 to coefficient of softing.
Specific embodiment
The application provides a kind of magnesium phosphate cement comprising: magnesia, potassium dihydrogen phosphate, sand, borax, flyash and water.
Wherein, the magnesium phosphorus molar ratio of cement be preferably 7.0-8.5, further preferably 7.0.
Wherein, water-cement ratio is preferably 0.18-0.21, and further preferably 0.21.
Wherein, borax volume is the 5%-10% of magnesia quality.
Wherein, the mass percent of coal ash instead magnesium phosphate cement is 15%, substitutes the quality meaning of magnesium phosphate cement
For, the quality of two kinds of substances of the magnesia for being to maintain magnesium phosphorus ratio and potassium dihydrogen phosphate of coal ash instead and.
Magnesia and phosphatic theoretical molar ratio are 1: 1, and still, due to the limitation of reaction condition, magnesia can not
Reaction is all participated in, cannot all be consumed, basic bone of the remaining unhydrated magnesium oxide particle as magnesium phosphate cement
Frame, therefore an optimal ratio is certainly existed for the reaction, so that the best performance of magnesium phosphate cement.Magnesium phosphorus ratio is to influence
The principal element of magnesium phosphate cement performance, since magnesia will not all participate in reaction process, a large amount of residue magnesium oxide particles are made
For skeleton, with hydrated product MgKPO4·6H2O is as Binder Phase, while matrix can be improved in a large amount of unhydrated magnesium oxide particles
Wear-resisting property, the determination of magnesium phosphorus ratio is most important for magnesium phosphate cement optimization of mix proportion, the present invention by test, magnesium
Phosphorus ratio is at 7.0, magnesium phosphate cement intensity with higher, good working performance and excellent fracture resistance.
Magnesium phosphate cement is more sensitive to water, therefore influence of the water-cement ratio for its performance is more significant, compares with magnesium phosphorus
Interaction often influences the deciding factor of magnesium phosphate cement mechanical performance and working performance.Magnesium phosphate cement workability
It can be influenced by water-cement ratio more obvious, as water-cement ratio increases, setting time increases therewith, and mobility is consequently increased, by force
Degree reduces.Water-cement ratio has an effect on the contraction and the performances such as porosity and permeability of magnesium phosphate cement, water-cement ratio at 0.21,
Magnesium phosphate cement intensity with higher, good working performance and excellent fracture resistance.
Due to magnesium phosphate cement hydration reaction fast speed, except through regulation raw material activity, specific surface area and it is matched
Outside, the most effective measure for extending setting time is exactly that retarder is added.Most common retarder have borax, boric acid, ammonium,
Sodium tripolyphosphate, alkali metal salt, at present using it is more be borax.
By verifying, for borax volume preferably within the scope of 5%-10%, borax can inhibit the dissolution of magnesium oxide particle, so that
Hydrated product crystal habit is irregular, thus shadow magnesium phosphate cement early anti pressured intension, when borax adds excess, magnesium phosphate water
There can be unhydrated borax particle in mud matrix, but since borax particle surface is smooth, reduce magnesium phosphate cement substrate
Between bond effect, to reduce the mechanical property of material entirety.Borax also has the shrinkage of magnesium phosphate cement
Certain to influence, with the increase of borax volume, the early stage of magnesium phosphate cement mortar and later period contraction distortion have a degree of
Increase, therefore, borax volume is unsuitable excessively high.
The admixture of flyash can reduce the cost of magnesium phosphate cement, on the other hand can improve the appearance of magnesium phosphate cement
Color is allowed to be more suitable for repairing work, can also improve magnesium phosphate cement intensity, and filling internal void makes magnesium phosphate cement more
Add densification, improves the water resistance of magnesium phosphate cement.
The present invention also provides the preparation methods of above-mentioned magnesium phosphate cement comprising:
The first step, weighs raw material according to calculating to match, and mortar stirring is added in magnesia, potassium dihydrogen phosphate, borax and sand
Pot, stirring at low speed 30s is uniformly mixed siccative, and then plus water stirs at low speed 30s blends raw material tentatively with water, last high-speed stirring
Mixing 90s is sufficiently mixed magnesium phosphate cement mortar uniformly；
Second step, the magnesium phosphate cement mortar after being sufficiently stirred is poured into die trial rapidly, while being placed to shake table
On, make the abundant vibration compacting of magnesium phosphate cement mortar, be subsequently placed in natural curing in air, conserves 3h demoulding；
Third step, after demoulding, by test block natural curing in air.
Below using embodiment and attached drawing come the embodiment that the present invention will be described in detail, how skill is applied to the present invention whereby
Art means solve technical problem, and the realization process for reaching technical effect can fully understand and implement.
Experiment
1, experimental raw
Magnesia is one of the primary raw material for participating in reaction, (is abbreviated as M, relative atom using dead burned magnesia in test
Quality 40.3), it is to be provided by Jinan, Shandong Province east in Shandong Province fire resisting Co., Ltd, by magnesite (MgCO3) by 1700 DEG C of calcinings, it breaks
Broken, ball milling forms, and color is light brown, and chemical composition is shown in Table 1, and primary particle size range is 60~85 μm.
1 magnesia primary chemical of table composition
| Composition | MgO | SiO2 | CaO | Fe2O3 | Al2O3 | Other |
| Content | 96.8 | 0.7 | 1.19 | 0.4 | 0.3 | 0.61 |
Potassium dihydrogen phosphate (being abbreviated as P, relative atomic mass 136.09) be also participate in MPC hydration reaction primary raw material it
One, potassium dihydrogen phosphate used is to analyze pure in this test, and content is greater than 99.5%, raw by Shanghai Ai Bi chemical reagent Co., Ltd
It produces, pH value is 4.2~4.5.
Borax (Na2B4O7·10H2O, Borax are abbreviated as B, relative atomic mass 381.37) it is anti-as magnesium phosphate cement
Common retarder in system is answered, is produced for Shanghai Ai Bi chemical reagent Co., Ltd, pure, content 99.5% is analyzed.
The practical micro- Chinese iso standard sand (being abbreviated as S) of this test China, is given birth to by Xiamen Aisiou Standard Sand Co., Ltd
It produces, every bag of weight is about 1350g, and the good sand grains of gradation meets GB/T14684-2001 standard.
Flyash (Fly Ash, be abbreviated as FA) is level-one flyash, main chemical compositions such as table 2.
2 flyash primary chemical of table composition
| Chemical constituent | CaO | SiO2 | MgO | Al2O3 | SO3 | Fe2O3 | K2O | Other |
| Content | 8.07 | 52 | 1.18 | 28.68 | 1.14 | 4.5 | 1.54 | 2.89 |
Water uses tap water.
Test device therefor
Cement mortar mixer, Vicat apparatus, flow of cement mortar tester, full-automatic pressure testing machine, 300KN are hydraulic
Omnipotent pressure testing machine and cement mortar shake table etc..
Experimental method
(1) it determines proportion, a variety of materials quality is calculated according to proportion and material purity.Proportion is mainly according to both at home and abroad
The material mixture ratio range of many scholar's researchs determines in present Research.
(2) according to proportion weighing raw material is calculated, the addition mortar such as magnesia, potassium dihydrogen phosphate, borax and normal sand is stirred
Pot is mixed, stirring at low speed 30s first is uniformly mixed siccative, and then plus water stirs at low speed 30s blends raw material tentatively with water, finally
High-speed stirred 90s is sufficiently mixed MPC mortar uniformly.
(3) the MPC mortar after being sufficiently stirred is poured into die trial rapidly, while being placed on shake table, and MPC mortar is made
Abundant vibration compacting is subsequently placed in natural curing in air, conserves 3h demoulding.
(4) after demoulding, by test block natural curing in air, then maintenance to regulation age measures its performance, main to survey
Trying age is 3h, 1d, 7d, 28d.
Die trial used in intensity test is 70.7mm × 70.7mm × 70.7mm, flexural strength test examination used in experiment
Mould is 40mm × 40mm × 160mm.
Setting time test
Setting time test is essentially according to standard GB/T/T1346-2001 " when cement normal consistency water consumption, condensation
Between, stability detection method " specified in normal process tested, using Vicat apparatus, calculated since mixture plus water solidifying
The time is tied, since MPC presetting period and final setting time difference are shorter, therefore using final setting time as the setting time of MPC mortar.Together
When due to the condensation of materials it is very fast, therefore setting time test interval wants short, and initial stage is primary every 30s test, every 10s after initial set
Test is primary, reduces test interval close to final set.
Fluidity test
Magnesium phosphate cement Mortar'S Flowability GB/T2419-2005 " Test method for fluidity of cement mortar " according to national standards
It is tested, i.e. jumping table method.
Pressure-proof and snap-resistent Mechanics Performance Testing
The flexural strength for testing mortar specimen predetermined age (3h, 1d, 7d, 28d), according to GB17671-1999 " cement gel
Sand ruggedness test method " test of testing, compression strength is using 70.7mm × 70.7mm × 70.7mm test block in omnipotent pressure
It tests, is tested according to " building mortar basic performance tests method " (JGJ/T70-2009) prescriptive procedure, often on testing machine
Group takes three test blocks, when in the test value of three test blocks a maximum or minimum value and median obtain difference more than median
When 15%, going median is effective compression strength, if maximin is above median and obtains 15%, then it is assumed that this group
Test block data invalid.
Water resistance evaluation
Evaluating common method for MPC water resistance is coefficient of softing, and since MPC is under Riddled Condition, intensity is easy
Retraction phenomenon occurs, the potassium dihydrogen phosphate that reason mainly has neither part nor lot in aquation can be partly dissolved, so defining softening system
It counts to evaluate the water resistance of MPC, is indicated with R, calculation are as follows:
Unconfined compressive strength after f- immersion, MPa；
Unconfined compressive strength under F- natural curing state, MPa；
R- coefficient of softing.
Influence of the magnesium phosphorus ratio (M/P) to setting time, the result is shown in Figure 1 and Fig. 2.
Phosphate is soluble easily in water, and hydration rate depends primarily on the rate of dissolution of MgO, and the solution rate of MgO is faster,
Reaction rate is faster, and setting time is shorter, therefore the fineness of magnesia, activity is equal all affect reaction rate also affect it is solidifying
Tie the time.In the case where magnesia fineness and activity (calcination temperature is larger to its activity influence) are certain, magnesia it is molten
Solution amount just affects early reaction rate, and therefore, different magnesium phosphorus ratios may result in setting time change.It is limited respectively in experiment
Determine water-cement ratio be 0.18 and 0.21 when, magnesium phosphorus compare setting time influence.
Can be seen that the reduction with magnesium phosphorus ratio from Fig. 1 and Fig. 2, setting time is on a declining curve, 4 are compared in magnesium phosphorus~
Setting time is more more obvious than changing with magnesium phosphorus in 5.5 ranges, changes after magnesium phosphorus ratio > 5.5 more gentle.Water-cement ratio is 0.21,
Setting time shortened to 13 minutes from 17 minutes, and main cause is that when magnesium phosphorus is smaller, content of magnesia is relatively fewer,
Its meltage becomes the principal element that the entire reaction of control carries out less.Meanwhile hydrated product production quantity is few, being formed has centainly by force
It is long the time required to the bonding of degree is whole.Another aspect content of magnesia is few, and borax is dissolved in the water the B to be formed4O7 2-, with oxidation
The lysigenous Mg of magnesium2+Complex compound MgB4O7It is preferable to the absorption package effect of magnesium oxide particle, play the role of protective film, it is right
Hinder Mg2+The effect contacted with each other with phosphate is preferable, and retarding effect is obvious.It is due to early period from the aspect of reaction temperature
Hydrated product production quantity is relatively fewer, and the heat generated in hydration process is relatively fewer, to the facilitation effect of reaction relative to it
He organizes weaker.Under the influence of the above a variety of factors, magnesium phosphorus extends than hour, setting time.With becoming larger for magnesium phosphorus ratio, oxidation
Magnesium dissolution increases, and the effective quantity that retarder borax forms protective film is reduced, and exothermic heat of reaction increases, and system temperature increases, aquation
Rate increases, and hydrated product production quantity gradually increases, and the speed for being interconnected to form space hardening system is accelerated, therefore condenses
Time is gradually shortened.
Magnesium phosphorus compares the influence of mobility, as a result sees Fig. 3 and Fig. 4.
Setting time can change with the variation of M/P value in reaction process, and mainly reaction rate is to hydration process shadow
Sound is larger, and hydration rate is high, and corresponding hydrated product production quantity will increase, and MPC slurry aquation hardening process will accordingly contract
It is short, to show mobility reduction.Simultaneous oxidation magnesium specific surface area also will affect MPC hydration process, and specific surface area increases, packet
The water consumption for wrapping up in magnesia just will increase.In the case where specific surface area is certain, magnesia volume increases, and can equally to use water
Amount increases, so, M/P is different, and MPC mobility also will receive corresponding influence.Since MPC hydration and hardening reaction process is very fast,
Setting time is shorter, therefore its fluidity testing will complete test within the time short as far as possible after completion of stirring, in order to avoid flowing
Property is excessively lost.When limiting water-cement ratio respectively as 0.18 and 0.21 in experiment, magnesium phosphorus compares the influence of mobility.
From figs. 3 and 4 it can be seen that MPC mortar mobility reduces with the increase of M/P when water-cement ratio is 0.18,
But its mobility variations is divided into two stages when water-cement ratio increases to 0.21, as M/P increases, mobility first increases
After reduce.Mobility strongly reduces when M/P increases to 10 from 8.5, drops to 140mm or so from 220mm.In mobility
The leading portion of variation, M/P increase mobility and increase, and mainly due to when M/P is smaller, MgO is less relative to phosphoric acid Saltstone,
Solution rate limits the progress of reaction, therefore hydrated product production quantity is slightly few, and free water content is high, to MPC mortar mobility
With larger contribution.As M/P increases, MgO volume increases, and dissolution increment increases, the Mg with phosphate reaction2+Increase, aquation
Product formation increases, therefore its mobility journey downward trend.On the other hand, M/P value increases, and a large amount of Free water is used to wrap up
MgO particle surface is MPC mortar lifting for mobility, but in the case where water consumption is certain, when Free water participates in hydration reaction
Process ratio increases, and Free water is not enough to soak MgO particle, and mobility is substantially reduced.
Magnesium phosphorus compares the influence of compression strength, sees Fig. 5 and Fig. 6.
Because dead burned magnesia solution rate is lower, not all magnesia can all participate in reacting, unhydrated oxygen
Change magnesium granules and serves as skeleton, hydrated product MgKPO4·6H2O can be used as Binder Phase, form the hardenite with some strength,
Intensity and the space structure for the Binder Phase that hydrated product is formed are closely related.Different M/P values affects the generation of hydrated product
Amount, either any component excessively can all significantly affect the integral strength of MPC mortar.Limited respectively in experiment water-cement ratio as
When 0.18 and 0.21, magnesium phosphorus compares the influence of compression strength.
With the growth of age, each proportion specimen intensity has apparent growth, especially intensity early period, and 3h intensity is basic
30MPa or more is all reached, 50%, the 1d intensity that can reach 28d intensity can reach the 70% of 28d intensity.Although studies have shown that
MPC mortar performance can change as M/P changes, and the production quantity of hydrated product changes, but its classification will not change
Become.M/P value is bigger than normal or the production quantity less than normal that can all influence hydrated product, and then influences hydrated product and form the complete of spatial network
Property, cause integral strength performance to decline.From Figures 5 and 6, it can be concluded that, when M/P value is 8.5 and 7, strength character is optimal.
Fig. 7 is variation relation of the different larval instar intensity with M/P value, by taking W/B is 0.21 as an example, with the increase of M/P, MPC mortar strength
Reduce variation afterwards in first increasing, main cause is that when M/P value is lesser, phosphate is relatively excessive, magnesia meltage
It is limited, the production quantity of hydrated product is constrained, to affect MgKPO4·6H2O forms the integrality of spatial network, and then leads
It causes under the M/P value, intensity is slightly smaller.When M/P value is larger, MgO is relatively excessive, and phosphatic content constrains hydrated product
Production quantity, therefore, intensity also shows lower.So between larger and lesser M/P value there are optimal magnesia and
Phosphate proportion.
Influence of the water-cement ratio (W/B) to setting time, is as a result shown in Fig. 8 and Fig. 9.
Water is not only used as one of reaction raw materials, but also exists as solvent, for the most important of MPC system.Engine request
Patching material is able to satisfy the construction time, under the premise of being able to satisfy intensity requirement, can adjust MPC setting time by W/B.Figure
Variation relation of the 8 and Fig. 9 between setting time and water-cement ratio.When magnesium phosphorus ratio is limited in experiment respectively as 7.0 and 8.5, glue
Compare the influence of mobility.
By Fig. 8 and Fig. 9, it is apparent that increasing with water-cement ratio, MPC mortar coagulation time gradually extends.Mainly
Since W/B increases, Free water increases in MPC mortar, increases the wetness degree of MgO particle surface, a large amount of Free water
So that MgKPO4·6H2O is not easy to be mutually lapped to form the space net structure with some strength.The specific heat capacity of water is larger, and water contains
The increase of amount absorbs a large amount of reaction heat, reduces system temperature, reduces reaction rate, and then it is solidifying to also play extension
Tie the effect of time.
Influence of the W/B to mobility, the result is shown in Figure 10 and Figure 11.
The change of water-cement ratio not only affects the variation of setting time, significantly changes while also result in mobility, flowing
Property be also considered one of the essential condition of construction.Mobility affects the density of structure, and mobility is too low, will lead to and is not easy
Vibration compacting, to influence the strength character of matrix.When limiting magnesium phosphorus ratio in experiment respectively as 7.0 and 8.5, water-cement ratio is to flowing
The influence of property.
As shown in Figure 10 and Figure 11, increase with water-cement ratio, mobility is obviously improved, and shows similar rule with setting time
Rule.The concrete reason that mobility improves is that W/B increases, and free water content increases in system, and MgO particle surface is sufficiently soaked,
Weaken the interaction between particle.It can also be seen that W/B is affected to the mobility of MPC matrix from figure, W/B increases
Long 0.3, mobility increases 100mm or so.
Influence of the W/B to MPC intensity, the result is shown in Figure 12 and Figure 13.
Water-cement ratio increases, and free water content increases in system, and the content of Free water will affect MPC mortar matrix in system
Pore size distribution$, W/B is higher, and pore structure is more coarse, and pore communication is bigger, gets over hence for the intensity effect of MPC mortar
Greatly.When magnesium phosphorus ratio is limited in experiment respectively as 7.0 and 5.5, influence of the water-cement ratio to compression strength.
From Figure 12 and Figure 13 it can be found that M/P it is excessive less than 7, W/B value or it is too small all make MPC mortar strength reduction,
The main reason is that M/P is certain, when glue is bigger, free water content increases in system, and a large amount of Free water is inside system
It cannot exclude, cause its internal harmful hole number to increase, to influence its strength characteristics, make its strength reduction.And W/B value is smaller
When, most of water is involved in hydration process, and Free water cannot be fully wrapped around by MgO particle in system, while hydration process is very fast,
Cause mobility lower, therefore, MPC mortar is not easy vibration compacting, and interior porosity increases, and leads to strength reduction.
As shown in figure 14, M/P value is greater than 7, increases with water-cement ratio, MPC mortar strength is on a declining curve.In the past described with M/
P value increases, and MPC mortar mobility reduces, and setting time shortens, and simultaneous oxidation magnesium is relatively excessive, and hydration reaction water consumption is reduced,
Excessive Free water, which is trapped in system, to be discharged, and system porosity is caused to increase, strength reduction, therefore W/B increases, intensity
It is on a declining curve.
Influence of the M/P and W/B to flexural strength, the result is shown in Figure 15.
In normal silicate concrete, matrix flexural strength is directly proportional to its compression strength, MPC cement mortar also table
Reveal same rule, as seen in Figure 15, with the increase of M/P, flexural strength is first increased and reduced afterwards, is 7 in M/P value
When, flexural strength has been up to 8.5MPa.Keeping M/P constant, it is found that increase with W/B value, flexural strength is also first to increase
Reduce after big, and shows more excellent fracture resistance when W/B is 0.21.
It can be seen that from experiment above in mono- timing of W/B, with the increase of M/P value, MPC mortar coagulation time is therewith
Shorten, but the flowing of MPC mortar is not the monotonic function of M/P value, when W/B is smaller, mobility is on a declining curve, still
When W/B is near 0.21, mobility variations trend is first to increase to reduce afterwards.Compression strength is reached in M/P value 7.0~8.5
To highest, but the factors such as setting time and mobility are considered simultaneously, performance when M/P value is 7.0 can satisfy usually
Repair demand of the rush construction engineering to material, intensity with higher and good working performance.
MPC mortar performance is more sensitive to the variation of W/B, and setting time extends with the increase of W/B value, mobility with
Increase.W/B will affect the pouring quality of its matrix while influencing MPC mortar mobility, and when value is smaller, sample is not easy
It pours closely knit, and then influences its integral strength, therefore W/B is unsuitable too small.W/B value is excessive, and MPC mortar coagulation time is shorter, greatly
The Free water of amount is not easy to be discharged, and system porosity increases, and also will lead to the reduction of MPC mortar strength, therefore is considering factors
Under the influence of, W/B shows preferable working performance and strength characteristics preferably near 0.21.
Flexural strength and compression strength show consistent changing rule, show when W/B value be 0.21, M/P value is 7.0
More excellent fracture resistance out.
Cost problem is the key factor for influencing magnesium phosphate cement and promoting, the adding coal ash meeting in normal concrete
Improve its basic property, therefore flyash is introduced into the study on the modification of magnesium phosphate cement.
Influence of the introducing of flyash to setting time and mobility, the result is shown in Figure 16 and Figure 17.
The water-cement ratio of magnesium phosphate cement is respectively 0.18 and 0.21 in experiment.From Figure 16 and Figure 17, it is apparent that
Flyash improves significantly to MPC plaster workability tool, and doping quantity of fly ash increases, the setting time of magnesium phosphate cement
Extending, mobility improves, but at doping quantity of fly ash smaller (less than 10%), it is very micro- for the prolongation effect of setting time
It is weak.Setting time it is extended the reason is that, after coal ash instead MPC its reaction raw materials reduce, hydrated product production quantity reduce, make
The chance that mutually being overlapped between MgO particle and fly ash grain by hydrated product forms space net structure is reduced, another party
Face is substantially not involved in hydration reaction since flyash is generally viewed as inert filler, and reactant is reduced, and hydration process generates
Heat reduce, MPC mortar temperature reduce, furthermore flyash can also adsorb PO4 3-Ion reduces MgKPO4·6H2O's
It is formed, to extend setting time.More obvious for the improvement of mobility, doping quantity of fly ash increases from 0%~30%, MPC
Mortar'S Flowability increases 50mm or so, and therefore, the admixture of flyash can be obviously improved the mobility of MPC mortar.Its convection current
The main reason for dynamic property improves is that the micro aggregate effect of flyash, flyash microstructure is mostly spheric granules, in system
Roller bearing effect is served as, the resistance between particle is reduced, to improve the mobility of MPC matrix.Mobility improves, another party
Face is also due to the reason of hydrated product production quantity is reduced.
Adulterate influence of the flyash to MPC compression strength, the result is shown in Figure 18 and Figure 19.
Adding coal ash can improve MPC strength character, by preliminary experiment it has also been found that its volume is strong to MPC 15% or so
Degree has improvement, while to mobility, setting time etc. is all improved, however mortar mobility and its setting time affect
The pouring quality of matrix, to also affect strength character, therefore have studied in test different water-binder ratios with it is difference flyash mixed
Measure the influence for MPC mortar strength.In experiment, the water-cement ratio of magnesium phosphate cement is respectively 0.18 and 0.21.
As shown in Figure 18 and Figure 19, with the increase of doping quantity of fly ash, when glue is smaller, after adding coal ash,
Intensity makes moderate progress, and when it is 28d that doping quantity of fly ash, which was 15% age, shows excellent strength character, compared to not adding
Flyash sample, intensity improve.However after water-cement ratio increases, with the increase of doping quantity of fly ash, MPC mortar strength becomes in decline
Gesture.It can be seen that there is different-effect under the flyash water-cement ratio state different for MPC matrix, under non-adding coal ash state,
When W/B value is smaller, MPC mortar mobility is relatively slightly lower, and setting time is shorter, and air entrapment is not easy to be discharged in forming process,
Being trapped in system makes component be not easy to pour closely knit, affects the strength character of MPC mortar.After flyash doping, mobility
Make moderate progress, setting time extend so that MPC be easier to pour it is closely knit, in addition, flyash micro aggregate effect effect under, fill out
The hole generated in MPC reaction process has been filled, the density of matrix is increased, so that intensity is improved.But with water
Than increasing, MPC mobility itself is promoted glue, and setting time can guarantee its pouring quality, at this point, after flyash doping, conduct
Inert filler, itself does not react substantially with MPC, while can also adsorb retarder, PO during the reaction4 3-Ion reduces
The pH value of system, impurity itself contained etc. can all influence MgKPO4·6H2The integrality of O space net structure, and then influence
The integral strength of MPC matrix.
After flyash doping, flexural strength is significantly improved, and compared to the control group of non-adding coal ash, works as flyash
When addition content is 10% or so, flexural strength is up to 7.3MPa, as shown in figure 20.
Influence of the addition of flyash to MPC water resistance.
MPC system meets water intensity for a long time and retraction phenomenon occurs, and coefficient of softing is to evaluate its retraction performance important indicator.Mineral
Admixture flyash, improves strength character, working performance and adhesive property of magnesium phosphate cement etc., while it is for magnesium phosphate
The water resistance of cement also has an impact, and in non-adding coal ash, conserves 28d in air, and intensity (uses R after the rear 7d that soaks
Indicate) change as shown in Figure 21 and Figure 23 (water-cement ratio 0.18).
Its coefficient of softing is calculated by formula, by two figures it will be evident that MPC mortar strength is decreased obviously after immersion, is soaked
Variation trends are substantially consistent with 28d Strength Changes after water, and when W/B is smaller, water resistance is mainly controlled by mobility, such as
Figure 22 and Figure 24, mobility hour, its coefficient of softing was relatively small, increased with mobility, and water resistance improves.Main cause is to flow
Dynamic property increases, and structure is more closely knit, KH2PO4It is only dissolved near surface, inside is not easy to be corroded by hydrone in short term.
Its intensity overall reduction is about 10% or so after immersion 7d, and when glue is bigger, coefficient of softing is with M/P value
Increase, be in raising trend, such as Figure 25.Main cause is KH2PO4It is soluble easily in water, and then will lead to MPC mortar mesoporous
Gap rate increases, and inside is more vulnerable to corrode, with the increase of M/P value, although flowing reduces, but unhydrated in MPC matrix
KH2PO4Content gradually decreases, and MPC is due to KH after reducing immersion2PO4The raised probability of happening of porosity caused by dissolution,
Therefore its coefficient of softing increases with M/P value and is increased.
After adding coal ash, Figure 26 is seen, when W/B is 0.18, MPC mortar mobility is improved, simultaneously because
The micro aggregate effect of flyash, a large amount of holes being filled in MPC increase MPC matrix compactness, therefore its water resistance is compared
It increases in non-adding coal ash MPC mortar.M/P is 7.0, W/B when being 0.18, and MPC mortar coefficient of softing only has 0.9, and
0.95 has been up to when flyash mixed dosage is 15%.
As can be seen from the above analysis, after adding hardened fly ashes, due to the micro aggregate effect of flyash, the flowing of MPC mortar
Property have apparent improvement, with the increase of doping quantity of fly ash, its mobility and setting time are all in and increase under different W/B states
Trend, but when doping quantity of fly ash less (being less than 10%), setting time extends less.
When W/B value is smaller, MPC mortar strength increases compared to for admixture group intensity after adding coal ash, mainly
Due to the improvement of mobility, the micro aggregate effect of pouring quality and flyash is improved, internal void is filled with, makes inside
Structure is finer and close, and intensity improves.As W/B increases, after adding coal ash, MPC mortar strength is on a declining curve, mainly due to
Flyash is considered as inert filler, does not react with MPC mortar matrix, flyash itself impurity effect MPC matrix it is complete
Whole property, strength reduction.
Water resistance and mobility have it is more close contact, when mobility is preferable, internal structure is more closely knit, in a short time not
Participate in the KH of aquation2PO4It not readily dissolves in water, reduces the raising of interior porosity, show preferable water resistance.W/B is
0.18, when doping quantity of fly ash is 15%, coefficient of softing has reached 0.95.
All above-mentioned this intellectual properties of primarily implementation, there is no this new products of implementation of setting limitation other forms
And/or new method.Those skilled in the art will utilize this important information, above content modification, to realize similar execution feelings
Condition.But all modifications or transformation belong to the right of reservation based on new product of the present invention.
The above described is only a preferred embodiment of the present invention, being not that the invention has other forms of limitations, appoint
What those skilled in the art changed or be modified as possibly also with the technology contents of the disclosure above equivalent variations etc.
Imitate embodiment.But without departing from the technical solutions of the present invention, according to the technical essence of the invention to above embodiments institute
Any simple modification, equivalent variations and the remodeling made, still fall within the protection scope of technical solution of the present invention.
Claims (7)
1. a kind of magnesium phosphate cement characterized by comprising magnesia, potassium dihydrogen phosphate, sand, borax, flyash and water.
2. phosphatase cement as described in claim 1, it is characterised in that: the magnesium phosphorus molar ratio of cement is 7.0-8.5.
3. phosphatase cement as claimed in claim 1 or 2, it is characterised in that: the magnesium phosphorus molar ratio of cement is 7.0.
4. phosphatase cement as described in claims 1 to 3, it is characterised in that: the water-cement ratio of cement is 0.18-0.21.
5. the phosphatase cement as described in Claims 1-4, it is characterised in that: the water-cement ratio of cement is 0.21.
6. the phosphatase cement as described in claim 1 to 5, it is characterised in that: borax volume is the 5%- of magnesia quality
10%.
7. the preparation method of claim 1 to 6 magnesium phosphate cement characterized by comprising
The first step, weighs raw material according to calculating to match, and mortar agitated kettle is added in magnesia, potassium dihydrogen phosphate, borax and sand, low
Speed stirring 30s is uniformly mixed siccative, and then plus water stirs at low speed 30s blends raw material tentatively with water, last high-speed stirred 90s
It is sufficiently mixed magnesium phosphate cement mortar uniformly；
Second step, the magnesium phosphate cement mortar after being sufficiently stirred is poured into die trial rapidly, while being placed on shake table, is made
The abundant vibration compacting of magnesium phosphate cement mortar is subsequently placed in natural curing in air, conserves 3h demoulding；
Third step, after demoulding, by test block natural curing in air.
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110282951A (en) * | 2019-07-12 | 2019-09-27 | 青岛理工大学 | A kind of magnesium phosphate cement base fast repairing material and its preparation method and application |
| CN111056815A (en) * | 2019-11-28 | 2020-04-24 | 广州市北二环交通科技有限公司 | Slow-setting high-toughness magnesium phosphate cement road rapid repair material |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050160944A1 (en) * | 2004-01-23 | 2005-07-28 | The University Of Chicago | Permafrost ceramicrete |
| CN101381219A (en) * | 2008-10-09 | 2009-03-11 | 上海交通大学 | Phosphate fast repairing building material |
| CN101880152A (en) * | 2010-06-04 | 2010-11-10 | 上海交通大学 | Reinforcing and repairing grouting material for construction in minus-temperature environment |
| CN108455964A (en) * | 2018-05-14 | 2018-08-28 | 东南大学 | A kind of environmentally friendly fast repairing material and preparation method thereof |
-
2019
- 2019-01-14 CN CN201910031164.3A patent/CN109626951A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20050160944A1 (en) * | 2004-01-23 | 2005-07-28 | The University Of Chicago | Permafrost ceramicrete |
| CN101381219A (en) * | 2008-10-09 | 2009-03-11 | 上海交通大学 | Phosphate fast repairing building material |
| CN101880152A (en) * | 2010-06-04 | 2010-11-10 | 上海交通大学 | Reinforcing and repairing grouting material for construction in minus-temperature environment |
| CN108455964A (en) * | 2018-05-14 | 2018-08-28 | 东南大学 | A kind of environmentally friendly fast repairing material and preparation method thereof |
Non-Patent Citations (2)
| Title |
|---|
| FEI QIAO ET AL.: ""Property evaluation of magnesium phosphate cement mortar as patch repair material"", 《CONSTRUCTION AND BUILDING MATERIALS》 * |
| 肖忠明，等: "《工业废渣在水泥生产中的应用》", 30 November 2009, 中国建材工业出版社 * |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN110282951A (en) * | 2019-07-12 | 2019-09-27 | 青岛理工大学 | A kind of magnesium phosphate cement base fast repairing material and its preparation method and application |
| CN111056815A (en) * | 2019-11-28 | 2020-04-24 | 广州市北二环交通科技有限公司 | Slow-setting high-toughness magnesium phosphate cement road rapid repair material |
| CN111056815B (en) * | 2019-11-28 | 2022-03-11 | 广州市北二环交通科技有限公司 | Slow-setting high-toughness magnesium phosphate cement road rapid repair material |
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