CN112897942A

CN112897942A - C35 concrete and preparation method thereof

Info

Publication number: CN112897942A
Application number: CN202110427629.4A
Authority: CN
Inventors: 左军平; 王育春
Original assignee: Shaanxi Fengdong Xincheng Concrete Co ltd
Current assignee: Shaanxi Fengdong Xincheng Concrete Co ltd
Priority date: 2021-04-20
Filing date: 2021-04-20
Publication date: 2021-06-04

Abstract

The application relates to the field of concrete, and particularly discloses C35 concrete and a preparation method thereof. The C35 concrete comprises the following raw materials: cement, fly ash, mineral powder, a temperature control admixture, coarse aggregate, fine aggregate, a water reducing agent and water; the temperature control admixture comprises a porous carrier and a phase change filler, wherein the phase change filler is filled in the pores of the porous carrier in a solid state, the cylinder pressure strength of the porous carrier is not less than 1.3MPa, and the phase change temperature of the phase change filler is between 45 and 54 ℃. The preparation method comprises the following steps: weighing raw materials, and dissolving a water reducing agent in water; uniformly stirring cement, fly ash, mineral powder, fine aggregate and water added with a water reducing agent to obtain a first mixture; adding the coarse aggregate into the first mixture, and uniformly stirring to obtain recycled aggregate concrete; the temperature control admixture is added with coarse aggregate or fine aggregate. The C35 concrete has the advantage of being not easy to crack due to thermal shrinkage; in addition, the preparation method has the advantage of being beneficial to improving the strength of concrete.

Description

C35 concrete and preparation method thereof

Technical Field

The application relates to the field of concrete, in particular to C35 concrete and a preparation method thereof.

Background

Concrete is a generic term for engineering composites where aggregates are cemented into a whole by cementitious materials. The concrete is cement concrete prepared with cement as cementing material, sand and stone as aggregate, admixture and water in certain proportion and through mixing. Concrete is generally graded according to strength, for example, C35 concrete refers to concrete cube test block with compressive strength value of 35MPa or more.

At present, C35 concrete is often used for some structure physical object concreting that minimum geometry is greater than 1m, because the concrete structure volume that forms is great, cement hydration can produce a large amount of heat of hydration, and the concrete is bad conductor again, and inside heat is difficult for giving out for can produce the uneven phenomenon of inside and outside temperature distribution after concrete placement a period of time, and too big difference in temperature will cause the concrete fracture, directly influences the structural safety of structure.

At present, in order to overcome temperature shrinkage cracks caused by concrete hydration heat, measures such as pre-buried cooling water pipes or construction by a bunker jump method are generally adopted in construction, the influence of the hydration heat on the quality of concrete can be reduced to a certain extent, but the improvement effect is limited, and the cost is greatly increased.

In view of the above-mentioned related art, the inventors believe that there is a defect that the concrete is likely to crack the structure due to the concentration of heat generated by hydration.

Disclosure of Invention

In order to solve the problem that concrete is prone to temperature shrinkage cracking, the application provides C35 concrete and a preparation method thereof.

In a first aspect, the present application provides a C35 concrete, which adopts the following technical solutions:

the C35 concrete is prepared from the following raw materials in parts by weight:

150 portions of cement and 170 portions of cement;

150 portions of fly ash and 170 portions of fly ash;

110 portions and 130 portions of mineral powder;

30-60 parts of temperature control admixture;

1050 portions of coarse aggregate and 1100 portions;

750 portions and 800 portions of fine aggregate;

3-5 parts of a water reducing agent;

130 portions of water and 150 portions of water;

the temperature control admixture comprises a porous carrier and a phase change filler, wherein the phase change filler is filled in the pores of the porous carrier in a solid state, the cylinder pressure strength of the porous carrier is not less than 1.3MPa, and the phase change temperature of the phase change filler is between 45 and 54 ℃.

By adopting the technical scheme, the porous carrier filled with the phase-change filler is used as the temperature control admixture, the phase-change filler is used as the temperature control material, and the characteristic that a large amount of heat needs to be absorbed in the phase-change process of the phase-change filler is utilized, so that the highest temperature rise temperature in the concrete solidification process is reduced, and the maximum temperature difference in the inner surface of the concrete is further reduced; and the porous carrier and the phase transition filler cooperation of adoption make the phase transition filler can with the cement contact in the concrete on the one hand, directly absorb the hydration heat of cement, promote heat conduction efficiency, on the other hand can also utilize porous carrier self intensity to reduce the not enough influence to the concrete intensity of phase transition filler intensity, be convenient for control the concrete intensity that makes, reduce the concrete and produce the crack possibility of temperature shrinkage, improve the easy temperature shrinkage crack's of concrete problem.

Optionally, the preparation method of the temperature-control admixture comprises the following steps:

s1, heating the phase-change filler to enable the phase-change filler to keep a liquid phase; placing the porous carrier in a closed environment, and vacuumizing to enable the closed environment to be in a negative pressure state;

s2, injecting the liquid-phase-change filler into the closed environment in a negative pressure state, so that the porous carrier is immersed in the liquid-phase-change filler, pressurizing the closed environment, and taking out the liquid-phase-change filler after the phase-change filler is cooled and solidified to obtain a semi-finished admixture;

and S3, crushing and vibrating the semi-finished product of the admixture to obtain the temperature-controlled admixture.

By adopting the technical scheme and the vacuum-pumping pretreatment, the air amount in the pores of the porous carrier is reduced, and the method is matched with the step of pressurizing auxiliary filling, so that the rapid filling of the phase-change filler in the phase-change porous carrier is facilitated on one hand, and the filling amount of the phase-change filler can be increased on the other hand; the mode of removing the phase change filler coated on the outer surface of the temperature control admixture by crushing and vibrating sieve is simple and efficient, the removing effect is good, and the removed phase change filler can be reused for filling the porous material, so that the loss is small.

Optionally, the phase change filler is paraffin or myristic acid.

By adopting the technical scheme, the paraffin or the p-tetradecanoic acid is used as the phase-change filler, and the characteristics of high latent heat value and appropriate phase-change temperature of the paraffin and the p-tetradecanoic acid are utilized, so that the highest temperature rise temperature in the concrete solidification process is favorably reduced, and the possibility of generating temperature shrinkage cracks in the concrete is further reduced.

Optionally, the porous carrier is macroporous adsorption resin or porous ceramsite.

By adopting the technical scheme, the macroporous adsorption resin is used as the porous carrier, and the characteristics of high porosity, small particle size and round and smooth particle shape of the macroporous adsorption resin are utilized, so that the filling capacity of the phase change filler is high, the improvement on the fluidity of concrete is facilitated, the workability of concrete is improved, the free water in the concrete can be adsorbed to swell to a certain degree, the free water serves as an expanding agent to compensate the thermal shrinkage of the concrete, and the possibility of generating shrinkage cracks in the concrete is further reduced.

The porous ceramsite is used as a porous carrier, and the characteristics of low porosity, high strength and low cost of the ceramsite are utilized, so that the temperature control effect can be fully exerted, the volume weight of the concrete is reduced, and the application range of the concrete is widened. Meanwhile, the filling of the phase-change filler can also improve the relative density of the porous ceramsite, has the effect of inhibiting the porous ceramsite from floating, is favorable for improving the distribution uniformity of the temperature-control admixture in the concrete, and improves the quality of the concrete.

Optionally, the porous ceramsite is obtained by polishing high-strength ceramsite to remove surface enamel.

By adopting the technical scheme, the high-strength ceramsite is polished to remove enamel on the surface of the high-strength ceramsite, so that pores in the high-strength ceramsite are exposed, the pores are open, the phase-change filler is conveniently filled, and the processing method is simple, convenient to operate, convenient and practical.

Optionally, the porous ceramsite is cleaned and dried after being polished.

By adopting the technical scheme, the porous ceramsite obtained by grinding is cleaned and dried to remove dust generated by grinding in the pores of the porous ceramsite, so that the pores of the porous ceramsite are fully exposed, the phase-change filler is conveniently filled, the connection strength of the phase-change filler filled in the pores of the porous ceramsite is improved, and the possibility of the phase-change filler falling out of the pores of the porous ceramsite is reduced.

Optionally, the porous ceramsite is cleaned and dried, and then is required to be placed in an acid solution for soaking and reaming, wherein the acid solution is a hydrochloric acid solution or a sulfuric acid solution.

By adopting the technical scheme, the porous ceramsite is soaked in the acid solution, and the acid solution is utilized to erode the pores and the surfaces of the porous ceramsite, so that the pore diameter of the pores of the porous ceramsite is increased to increase the capacity of the phase-change filler, and the roughness of the outer surface and the pore surface of the porous ceramsite is increased to increase the connection strength between the porous ceramsite and the cement and between the phase-change filler and the porous ceramsite, reduce the use loss rate of the temperature-control admixture, and contribute to improving the strength of the concrete.

Optionally, the pH value of the acid solution is 1-2, and the soaking time is 1-1.5 h.

By adopting the technical scheme, the pore space of the porous ceramsite soaked by the acid solution is enlarged, the surface roughness is increased, the influence on the strength of the porous ceramsite is small, the quality stability of concrete is favorably improved, and the control on the strength of the concrete is facilitated.

In a second aspect, the present application provides a method for preparing C35 concrete, which adopts the following technical scheme:

a preparation method of C35 concrete comprises the following steps:

weighing raw materials according to a ratio, and dissolving a water reducing agent in water;

step two, stirring and mixing cement, fly ash, mineral powder, fine aggregate and water added with a water reducing agent uniformly to obtain a first mixture;

adding the coarse aggregate into the first mixture, and uniformly stirring to obtain recycled aggregate concrete;

wherein, the temperature control admixture is added in the second step or the third step; when the porous carrier adopts macroporous adsorption resin, the temperature control admixture is added together with cement in the second step; when the porous carrier adopts porous ceramsite, the temperature control admixture is added together with the coarse aggregate in the third step.

By adopting the technical scheme, the cement mortar which is uniformly mixed is prepared firstly through twice feeding, and then the coarse aggregate is added, so that the prepared cement mortar can fully and uniformly wrap the coarse aggregate, the interface thickness uniformity of the coarse aggregate is promoted, and the strength of the concrete is further promoted.

In summary, the present application has the following beneficial effects:

1. according to the concrete temperature control admixture, the porous carrier filled with the phase change filler is used as the temperature control admixture, and the characteristic that a large amount of heat needs to be absorbed in the phase change process of the phase change filler is utilized to reduce the highest temperature rise temperature in the concrete solidification process, so that the maximum temperature difference in the inner surface of the concrete is reduced, the possibility of temperature shrinkage cracks of the concrete is reduced, and the problem that the concrete is prone to temperature shrinkage cracking is solved;

2. the vacuumizing pretreatment is adopted during the preparation of the temperature-control admixture, so that the air amount in the pores of the porous carrier is reduced, and the vacuumizing pretreatment is matched with the step of pressurizing auxiliary filling, so that on one hand, the rapid filling of the phase-change filler in the phase-change porous carrier is facilitated, on the other hand, the filling amount of the phase-change filler can be increased, and the temperature rise resistance of concrete is further promoted;

3. according to the method, the cement mortar which is uniformly mixed is prepared firstly through twice feeding, and then the coarse aggregate is added, so that the prepared cement mortar fully and uniformly wraps the coarse aggregate, the interface thickness uniformity of the coarse aggregate is promoted, and the strength of the concrete is further promoted.

Detailed Description

The present application will be described in further detail with reference to examples.

The information of the main raw materials mentioned in the following is shown in Table 1, and the rest raw materials are all common commercial products.

Table 1 raw material information table

Preparation example of temperature-controlled Admixture

Preparation example 1

A preparation process of a temperature control admixture specifically comprises the following steps:

s1, placing 10kg of paraffin in a heating furnace, heating to 60 ℃ so that the paraffin is molten and kept in a liquid state; 10kg of macroporous adsorption resin is placed in a reaction kettle, the reaction kettle is vacuumized by a vacuum pump, and the interior of the reaction kettle is adjusted to a negative pressure environment with the relative vacuum degree of-0.08 MPa.

S2, heating the temperature in the reaction kettle in a negative pressure state to 60 ℃, injecting liquid paraffin into the reaction kettle through a pipeline to immerse the macroporous adsorption resin in the liquid paraffin, adjusting the pressure in the reaction kettle to a pressurization state with a relative vacuum degree of 0.1MPa through a booster pump, and taking out the liquid paraffin after the liquid paraffin is cooled to room temperature and solidified to obtain a finished admixture;

and S3, putting the semi-finished admixture into a crusher for crushing, and then performing vibration screening by using a vibrating screen machine to obtain the temperature-controlled admixture.

Preparation example 2

The preparation process of the temperature-controlled admixture is different from the preparation example 1 in that: in S1, the autoclave was not evacuated, and in S2, the autoclave was not pressurized.

Preparation example 3

The preparation process of the temperature-controlled admixture is different from the preparation example 1 in that: the phase-change filler adopts myristic acid.

Preparation example 4

The preparation process of the temperature-controlled admixture is different from the preparation example 1 in that: the porous carrier adopts porous ceramsite, and the preparation steps of the porous ceramsite are as follows: and (3) polishing the high-strength ceramsite in a shot blasting machine, and removing enamel on the surface of the high-strength ceramsite to expose pores in the high-strength ceramsite to obtain the porous ceramsite.

Preparation example 5

The preparation process of the temperature-controlled admixture is different from the preparation example 4 in that: the porous ceramsite also needs to be cleaned before use, and the porous ceramsite is naturally dried after being cleaned.

Preparation example 6

The preparation process of the temperature-controlled admixture is different from the preparation example 5 in that: after being dried, the porous ceramsite also needs to be subjected to acid etching, and the method specifically comprises the following steps: and placing the dried porous ceramsite in a soaking pool, adding a hydrochloric acid solution with the pH value of 2 into a stirring tank, soaking the porous ceramsite for 1.5h, taking out and drying for later use.

Preparation example 7

The preparation process of the temperature-controlled admixture is different from the preparation example 6 in that: when the porous ceramsite is subjected to acid etching, the porous ceramsite is soaked for 1 hour by using a hydrochloric acid solution with the pH value of 1.

Preparation example 8

The preparation process of the temperature-controlled admixture is different from the preparation example 6 in that: when the porous ceramsite is subjected to acid etching, the porous ceramsite is soaked for 0.8h by using a hydrochloric acid solution with the pH value of 0.5.

Preparation example 9

The preparation process of the temperature-controlled admixture is different from the preparation example 6 in that: the acid solution used for acid etching of the porous ceramsite is nitric acid solution.

Preparation example 10

The preparation process of the temperature-controlled admixture is different from the preparation example 4 in that: the porous ceramsite is prepared from building ceramsite.

Performance detection

test-Strength detection

The cylinder pressure strength detection is carried out on the macroporous adsorption resin, the high-strength ceramsite, the building ceramsite and the porous carrier adopted in the preparation examples 4-10, and the detection method comprises the following steps:

1. taking high-strength ceramsite, building ceramsite and porous ceramsite with the particle size of 10-15mm as a sample by using macroporous adsorption resin or a sieve;

2. filling a sample by using a pressure-bearing cylinder, respectively measuring the weight of the loose materials for 3 times, taking the arithmetic mean value of the weight of the loose materials, and taking the product of the measured average weight of the loose materials and the filling coefficient of 1.10 as the sample amount;

3. weighing the sample according to the sample amount, filling the sample into a pressure bearing cylinder, firstly tapping for a plurality of times along the periphery of the cylinder wall by using a wooden hammer, then installing a guide cylinder and a stamping die, checking whether the lower scale mark of the stamping die is overlapped with the upper edge of the guide cylinder or not, if not, tapping the periphery of the cylinder wall again until the lower scale mark is completely overlapped; placing the pressure-bearing cylinder on a lower pressing plate of a press, and uniformly loading at a speed of about 30-50kg per second; when the press-in depth of the press die is 20mm, the pressure value is recorded.

And (3) detection results: as shown in table 2.

TABLE 2 Cylinder pressure Strength test results

Sample (I)	Barrel pressure strength/MPa
		Macroporous adsorbent resin	2.58
High-strength ceramsite	3.21
		Building ceramsite	1.3
Preparation example 4 porous support	1.85
		Preparation example 5 porous support	1.81
Preparation example 6 porous support	1.76
		Preparation example 7 porous support	1.75
Preparation example 8 porous support	1.47
		Preparation example 9 porous Carrier	1.15
Preparation example 10 porous support	0.62

Test two bond Strength and Capacity testing

The temperature-controlled admixture prepared in the examples 1 to 10 was subjected to detection of the bonding strength between the phase change filler and the porous carrier and detection of the containing amount, the detection method was as follows:

1. weighing 1kg of temperature-controlled admixture as a sample, placing the sample in a stirrer to be stirred for 1min, taking out and sieving the sample, and weighing the weight of undersize;

2. heating the screen residue on a screen mesh to keep the temperature of the screen residue above 60 ℃ so as to melt the paraffin in the temperature control admixture, periodically shaking the screen mesh in the heating process until no liquid paraffin is separated out on the porous carrier, and weighing the weight of the porous carrier;

3. the difference is made between the weighed weight of the porous carrier and the original weight (1kg) of the temperature control admixture, and the obtained numerical value is the weight of the phase change filler contained in the 1kg of the temperature control admixture; the weight ratio of the undersize to the weight of the phase-change filler is taken as the bonding index of the phase-change filler, and the larger the bonding index is, the poorer the bonding strength of the phase-change filler and the porous carrier is.

And (3) test results: as shown in table 3.

TABLE 3 Containment and bond Strength of phase-change fillers in temperature-controlled admixtures according to preparation examples 1 to 10

Sample (I)	Undersize weight/kg	Weight/kg of porous support	Phase change filler content/kg	Index of binding property
					Preparation example 1	0.081	0.651	0.349	0.232
Preparation example 2	0.058	0.778	0.222	0.261
					Preparation example 3	0.079	0.662	0.338	0.234
Preparation example 4	0.061	0.749	0.251	0.243
					Preparation example 5	0.058	0.730	0.27	0.215
Preparation example 6	0.052	0.689	0.311	0.167
					Preparation example 7	0.053	0.691	0.309	0.172
Preparation example 8	0.044	0.633	0.367	0.120
					Preparation example 9	0.048	0.650	0.35	0.137
Preparation example 10	0.068	0.721	0.279	0.244

Examples

Example 1

The raw material components and the corresponding weight of the C35 concrete are shown in Table 4, and the concrete preparation steps are as follows:

weighing raw materials according to the mixture ratio recorded in the table 4, dissolving a water reducing agent in water, and uniformly stirring the water reducing agent in a stirring tank;

adding cement, fly ash, mineral powder, fine aggregate, a temperature control admixture and water added with a water reducing agent into a concrete mixer, and stirring for 1min to uniformly mix the cement, the fly ash, the mineral powder, the fine aggregate, the temperature control admixture and the water added with the water reducing agent to obtain a first mixture;

adding the coarse aggregate into a concrete mixer filled with the first mixture, and stirring for 30s to obtain uniformly-stirred recycled aggregate concrete;

wherein the temperature control admixture adopted is prepared by the preparation example 2.

Adding the temperature control admixture in the second step or the third step; when the porous carrier adopts macroporous adsorption resin, the temperature-control admixture is added together with the cement in the second step; when the porous carrier adopts porous ceramsite, the temperature control admixture is added together with the coarse aggregate in the third step.

Example 2

A C35 concrete, which is different from example 1 in that the raw material components and the corresponding weights thereof are shown in Table 4.

Example 3

Table 4 examples 1-3 raw material compositions and corresponding weights (kg)

Components	Preparation example 1	Preparation example 2	Preparation example 3
				Cement	30	32	34
Fly ash	34	32	30
				Mineral powder	26	24	22
Temperature control admixture	12	9	6
				Coarse aggregate	210	215	220
Fine aggregate	150	155	160
				Water reducing agent	0.6	0.8	1
Water (W)	30	28	26

Example 4

A C35 concrete different from example 1 in that the temperature-controlling admixture used was prepared by the method of preparation example 2.

Example 5

A C35 concrete different from example 1 in that the temperature-controlling admixture was prepared by the method of preparation example 3.

Example 6

A C35 concrete different from example 1 in that the temperature-controlling admixture was prepared by the method of preparation example 4 and the temperature-controlling admixture was added with the coarse aggregate in step three.

Example 7

A C35 concrete different from example 6 in that the temperature-controlling admixture was prepared by the process of preparation 5.

Example 8

A C35 concrete different from example 6 in that the temperature-controlling admixture was prepared by the process of preparation 6.

Example 9

A C35 concrete different from example 6 in that the temperature-controlling admixture was prepared by the process of preparation example 7.

Example 10

A C35 concrete different from example 6 in that the temperature-controlling admixture was prepared by the process of preparation 8.

Example 11

A C35 concrete different from example 6 in that the temperature-controlling admixture was prepared by the process of preparation 9.

Comparative example

Comparative example 1

The concrete preparation steps of the C35 concrete are as follows:

weighing 30kg of cement, 34kg of fly ash, 26kg of mineral powder, 210kg of coarse aggregate, 162kg of fine aggregate, 0.6kg of water reducing agent and 30kg of water, dissolving the water reducing agent in the water, and uniformly stirring the water reducing agent in a stirring tank;

adding cement, fly ash, mineral powder, fine aggregate and water added with a water reducing agent into a concrete mixer, and stirring for 1min to uniformly mix the cement, the fly ash, the mineral powder, the fine aggregate and the water added with the water reducing agent to obtain a first mixture;

and step three, adding the coarse aggregate into the concrete mixer filled with the first mixture, and stirring for 30s to obtain the uniformly-stirred recycled aggregate concrete.

Comparative example 2

A C35 concrete different from example 1 in that the temperature-controlling admixture was prepared by the process of preparation example 10.

Performance detection

Test-compressive Strength detection

Test subjects: c35 concrete prepared according to examples 1-11 and comparative examples 1-2.

Test samples: and manufacturing a test piece sample according to a 5 th part of test piece manufacturing and maintaining method in standard of testing methods of mechanical properties of common concrete (GBT 50081-2002) and maintaining the test piece sample.

The test method comprises the following steps: the 90-day compressive strength test is carried out on the event sample reaching the curing age according to the test method of part 6 of the test method standard of mechanical properties of common concrete (GBT 50081-2002).

And (3) test results: as shown in table 5.

Test two adiabatic temperature rise detection

The test method comprises the following steps: the 7d adiabatic temperature rise test was carried out according to the 4.18 part concrete adiabatic temperature rise test method in the Hydraulic concrete test protocol (DLT 5150-2017).

And (3) test results: as shown in table 5.

Test three-shrinkage Performance test

The test method comprises the following steps: the 28d self-shrinkage test was carried out according to the non-contact method in the 8 th part shrinkage test in the Standard test methods for Long-term Performance and durability of ordinary concrete (GBT 50082-2009).

And (3) test results: as shown in table 5.

Test four crack condition detection

Test subjects: the concrete produced in examples 1 to 11 and comparative examples 1 to 2.

The test method comprises the following steps: the total crack area per unit area is detected according to the 9 th part early crack test method in the standard of test methods for long-term performance and durability of ordinary concrete (GBT 50082-2009).

And (3) test results: as shown in table 5.

TABLE 5 test results

It can be seen from the combination of examples 1 to 11 and comparative example 1 and table 5 that, after the temperature control admixture is further doped into the concrete, the adiabatic temperature rise of the concrete 7d, the 28d self-shrinkage rate and the total cracking area per unit area are all significantly reduced, and the compressive strength of the concrete 90d is significantly improved, because the phase-change filler absorbs a part of heat in the process of increasing the internal temperature of the concrete, so as to reduce the internal temperature rise speed of the concrete, and when the internal temperature of the concrete rises to be close to the melting point of the phase-change filler, because the latent heat of the phase-change filler is higher, a large amount of heat is absorbed, so that the internal temperature rise speed of the concrete is further slowed down or even stopped, the time from the maximum adiabatic temperature peak is delayed, and the concrete continuously dissipates heat in the prolonged period of time, so that the total amount of hydration heat stored in the concrete is reduced, thereby achieving the effect of, the temperature difference between the inside and the outside of the concrete is reduced, the shrinkage of the concrete and the generation of temperature shrinkage cracks are reduced, and the strength of the concrete is improved.

It can be seen from the combination of example 1 and comparative example 2 and table 5 that when the porous carrier used is low in strength, the strength of the concrete is significantly reduced because the low-strength porous carrier is broken when an external load is applied, so that the porous carrier becomes a structural weakness in the concrete, directly affecting the strength of the concrete.

It can be seen from the combination of examples 1-3 and table 5 that the use of fly ash and mineral powder as a cementing material instead of part of cement is helpful to reduce the hydration heat of concrete, thereby reducing the total cracking neps in unit area of concrete and improving the strength of concrete.

As can be seen by combining examples 1 and 4 and tables 3, 5 and 6, the operations of vacuumizing and pressurizing during the preparation process are helpful to increase the filling amount of the phase-change filler in the porous carrier, so as to increase the hydration heat absorbed by the phase-change filler and reduce the generation of concrete temperature shrinkage cracks; but also can promote the bonding strength between phase change filler and the porous carrier for the phase change filler in the temperature control admixture is difficult for deviating from in the concrete preparation stirring process, reduces the volume of the phase change filler directly doped into the concrete raw material, and then reduces the influence of the use of the phase change filler on the concrete strength.

It can be seen from the combination of examples 1 and 5 and tables 5 and 6 that, when tetradecanoic acid is used as the phase-change filler, the influence on the temperature difference between the inside and the outside of the concrete is less than that of paraffin wax due to the higher melting point of the tetradecanoic acid, but the generation of concrete shrinkage cracks can also be reduced, and the strength of the concrete can be improved.

It can be seen from the combination of examples 1 and 6 and tables 5 and 6 that the amount of the phase change filler contained in the porous ceramsite is lower than that of the macroporous adsorbent resin, but the effect of improving the cracking problem of concrete due to thermal shrinkage can still be achieved, and the cost of the porous ceramsite is higher than that of the porous adsorbent resin, so that the cost performance of the porous ceramsite is relatively lower, and the porous ceramsite is more suitable for large-scale application.

It can be seen from the combination of examples 6 and 7 and tables 5 and 6 that the use of the cleaned and dried porous ceramsite as the porous carrier is helpful for increasing the pore volume of the porous ceramsite, further increasing the capacity of the phase change filler, further absorbing the hydration heat of the concrete, reducing the generation of temperature shrinkage cracks in the concrete, and increasing the strength of the concrete.

It can be seen from the combination of examples 6 and 8 to 11 and tables 5 and 6 that the porous ceramsite is subjected to acid etching, so that the pore volume of the porous ceramsite is expanded, the accommodation capacity of the porous ceramsite to the phase-change filler is increased, and the temperature control performance of the temperature control admixture is improved.

The present embodiment is only for explaining the present application, and it is not limited to the present application, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present application.

Claims

1. The C35 concrete is characterized by being prepared from the following raw materials in parts by weight:

150 portions of cement and 170 portions of cement;

150 portions of fly ash and 170 portions of fly ash;

110 portions and 130 portions of mineral powder;

30-60 parts of temperature control admixture;

1050 portions of coarse aggregate and 1100 portions;

750 portions and 800 portions of fine aggregate;

3-5 parts of a water reducing agent;

130 portions of water and 150 portions of water;

2. The C35 concrete according to claim 1, wherein: the preparation method of the temperature-control admixture comprises the following steps:

3. The C35 concrete according to claim 1, wherein: the phase change filler is paraffin or myristic acid.

4. The C35 concrete according to claim 1, wherein: the porous carrier is macroporous adsorption resin or porous ceramsite.

5. The C35 concrete of claim 4, wherein: the porous ceramsite is obtained by polishing high-strength ceramsite and removing surface enamel.

6. The C35 concrete of claim 5, wherein: the porous ceramsite is also required to be cleaned and dried after being polished.

7. The C35 concrete of claim 6, wherein: after being cleaned and dried, the porous ceramsite also needs to be placed in an acid solution for soaking and reaming, wherein the acid solution is a hydrochloric acid solution or a sulfuric acid solution.

8. The C35 concrete of claim 7, wherein: the pH value of the acid solution is between 1 and 2, and the soaking time is 1 to 1.5 hours.

9. The method of preparing the C35 concrete of claims 1-8, comprising the steps of: