1. The anti-permeability and anti-cracking concrete is characterized by comprising the following raw materials in parts by weight:

170-220 parts of cement;

coarse aggregate: 640-680 parts;

fine aggregate: 530-570 parts;

160-220 parts of water;

30-60 parts of volcanic ash;

12-16 parts of fiber aggregate;

7.0-8.5 parts of a fiber modifier;

the fiber modifier is prepared by mixing the following raw materials in parts by weight: 1.7-2.4 parts of maleic anhydride, 7.2-9 parts of allyl polyoxyethylene ether, 1.3-1.8 parts of polytetrahydrofuran, 2.6-3.6 parts of ammonium persulfate and 1.5-1.9 parts of polypropylene glycol.

2. The impermeable and anti-cracking concrete as claimed in claim 1, wherein:

the fiber modifier is prepared by mixing the following raw materials in parts by weight: 1.9-2.1 parts of maleic anhydride, 7.6-8.4 parts of allyl polyoxyethylene ether, 1.45-1.65 parts of polytetrahydrofuran, 3.0-3.3 parts of ammonium persulfate and 1.64-1.72 parts of polypropylene glycol.

3. The impermeable and anti-cracking concrete as claimed in claim 1 or 2, which is characterized in that:

the molecular weight of the polypropylene glycol is 200-600.

4. The impermeable and anti-cracking concrete as claimed in claim 1 or 2, which is characterized in that:

the fiber aggregate comprises 65-75% by weight of polypropylene steel-like fibers and the balance of sepiolite fibers.

5. The impermeable and anti-cracking concrete as claimed in claim 4, wherein: the thickness of the polypropylene imitation steel fiber is 1200-1500D.

6. The preparation method of the anti-permeability and anti-cracking concrete as claimed in any one of claims 1 to 5, which is characterized by comprising the following preparation steps of:

the method comprises the following steps: uniformly mixing maleic anhydride, allyl polyoxyethylene ether, polytetrahydrofuran, ammonium persulfate and polypropylene glycol, heating to 70-90 ℃, keeping the temperature for 30-45 min, and continuously stirring in the constant temperature process to obtain a fiber modifier;

step two: cooling the fiber modifier to 50-60 ℃, adding the fiber aggregate, stirring for 10-20 min, and keeping the stirring process at a constant temperature to obtain an improved fiber aggregate;

step three: the volcanic ash, the cement, the water, the coarse aggregate, the fine aggregate and the improved fiber aggregate are uniformly mixed to obtain the anti-permeability and anti-cracking concrete.

7. The preparation method of the anti-permeability and anti-cracking concrete as claimed in claim 6, wherein the preparation method comprises the following steps: the temperature rise in the first step is 75-85 ℃.

8. The preparation method of the anti-permeability and anti-cracking concrete as claimed in claim 6, wherein the preparation method comprises the following steps: the temperature rise speed in the first step is 5-8 ℃/min.

Background

As the most widely and important basic material in the current building field, the concrete has the advantages of high strength, simple construction, low cost and the like.

The gel material in the concrete and water generate hydration reaction to generate a viscous hydration product, which not only can play a role in bonding the sandstone aggregate in the concrete, but also can harden the concrete structure, thereby leading the concrete to have good bearing rigidity.

However, since the hydration reaction of the concrete generates a certain reaction heat, the later plastic shrinkage of the concrete caused by the reaction heat easily causes the internal cracking of the concrete, and the internal cracking not only makes the water easily permeate into the concrete, but also reduces the anti-cracking strength of the concrete, and directly affects the service life of the concrete. Therefore, how to improve the internal structure defects of the concrete to improve the seepage-proofing and crack-resisting performance of the concrete has important significance.

Disclosure of Invention

In order to improve the anti-permeability and anti-cracking performance of concrete, the application provides anti-permeability and anti-cracking concrete and a preparation method thereof.

In a first aspect, the application provides an impervious anti-cracking concrete, which adopts the following technical scheme:

the anti-permeability and anti-cracking concrete comprises the following raw materials in parts by weight:

170-220 parts of cement;

coarse aggregate: 640-680 parts;

fine aggregate: 530-570 parts;

160-220 parts of water;

30-60 parts of volcanic ash;

12-16 parts of fiber aggregate;

7.0-8.5 parts of a fiber modifier;

the fiber modifier is prepared by mixing the following raw materials in parts by weight: 1.7-2.4 parts of maleic anhydride, 7.2-9 parts of allyl polyoxyethylene ether, 1.3-1.8 parts of polytetrahydrofuran, 2.6-3.6 parts of ammonium persulfate and 1.5-1.9 parts of polypropylene glycol.

Preferably, the fiber modifier is prepared by mixing the following raw materials in parts by weight: 1.9-2.1 parts of maleic anhydride, 7.6-8.4 parts of allyl polyoxyethylene ether, 1.45-1.65 parts of polytetrahydrofuran, 3.0-3.3 parts of ammonium persulfate and 1.64-1.72 parts of polypropylene glycol.

By adopting the technical scheme, the fiber modifier prepared from maleic anhydride, allyl polyoxyethylene ether, polytetrahydrofuran, ammonium persulfate and polypropylene glycol has a modification effect on fiber aggregate, and is in matched reaction with volcanic ash, so that the slump and the water seepage height of concrete are reduced, the splitting tensile strength of the concrete is improved, and the concrete has good construction performance, impermeability and anti-cracking performance.

Maleic anhydride, allyl polyoxyethylene ether and polytetrahydrofuran interact with the fiber aggregate under the environment of ammonium persulfate and polypropylene glycol, carboxylate radicals and polyether radicals with strong polarity are possibly grafted on the surface of the fiber aggregate, so that the fiber aggregate has good dispersibility in concrete, long ether chains are accumulated on the surface of cement particles to form a hydration membrane, the movement of water molecules is restrained to delay hydration reaction, internal cracks caused by intense heat release in the hydration process are relieved, the concrete has good water retention and workability, the slump of the concrete is reduced, in addition, the carboxylate radicals on the surface of the fiber aggregate can have good chelation with metal ions separated out from volcanic ash, the volcanic ash can be uniformly adhered to fibers, and the volcanic ash can play a role in filling fine pores between the fiber aggregate and inorganic aggregate in the later hydration reaction, the fiber aggregate has better cohesiveness in concrete, thereby improving the strength of the internal structure of the concrete, the hydration reaction of the concrete in the curing process is slow and stable, the internal structure of the concrete is more compact, and the concrete has obvious excellence in crack resistance and impermeability.

Preferably, the molecular weight of the polypropylene glycol is 200 to 600.

By adopting the technical scheme, the polypropylene glycol with the molecular weight within a certain range can have proper dispersibility among the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran, so that the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran are not easy to agglomerate pairwise, the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran can better interact, and the modification effect on the fiber aggregate is improved.

Preferably, 65-75% of the fiber aggregate in parts by weight is polypropylene steel-like fiber, and the balance is sepiolite fiber.

By adopting the technical scheme, the polypropylene steel-like fiber and the sepiolite fiber are matched with each other, so that the fiber modifier has better compatibility and permeability to the polypropylene steel-like fiber and the sepiolite fiber, and the action effect of the fiber modifier is improved.

Preferably, the thickness of the polypropylene imitation steel fiber is 1200-1500D.

By adopting the technical scheme, the appropriate fiber thickness can improve the impermeability and the anti-cracking performance of the concrete more balance.

In a second aspect, the application provides a preparation method of anti-permeability and anti-cracking concrete, which adopts the following technical scheme: a preparation method of anti-permeability and anti-cracking concrete comprises the following preparation steps:

the method comprises the following steps: uniformly mixing maleic anhydride, allyl polyoxyethylene ether, polytetrahydrofuran, ammonium persulfate and polypropylene glycol, heating to 70-90 ℃, keeping the temperature for 30-45 min, and continuously stirring in the constant temperature process to obtain a fiber modifier;

step two: cooling the fiber modifier to 50-60 ℃, adding the fiber aggregate, stirring for 10-20 min, and keeping the stirring process at a constant temperature to obtain an improved fiber aggregate;

step three: the volcanic ash, the cement, the water, the coarse aggregate, the fine aggregate and the improved fiber aggregate are uniformly mixed to obtain the anti-permeability and anti-cracking concrete.

Preferably, the temperature rise in the first step is 75-85 ℃.

By adopting the technical scheme, the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol are mixed and heated to a certain temperature range for constant temperature treatment, so that the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran are better mutually matched and influenced, better modification effect can be realized on fiber aggregates, volcanic ash adhered to the surfaces of the modified fiber aggregates is more uniform, the fiber aggregates and the volcanic ash are better mutually matched and act on concrete, the compactness of an internal structure is improved, and the concrete has good anti-cracking and anti-seepage performance.

Preferably, the temperature rise speed in the first step is 5-8 ℃/min.

By adopting the technical scheme, the temperature rise of the reaction of the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol is controlled, so that the reaction of the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran is smoothly carried out, the reaction is possibly more complete, the reaction product amount with a modification effect on the fiber aggregate is increased, and the impermeability and anti-cracking performance of the concrete are better.

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

1. because the fiber modifier prepared by mixing maleic anhydride, allyl polyoxyethylene ether, polytetrahydrofuran, ammonium persulfate and polypropylene glycol is adopted to modify the fiber aggregate, the modified fiber aggregate and volcanic ash are matched to act on concrete together, so that the hydration reaction of the concrete is stably carried out, the internal cracking of the concrete caused by the over-strong early hydration reaction is reduced, the internal structure of the concrete is more compact, and the impermeability and the anti-cracking performance of the concrete are obviously improved;

2. according to the method, the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol are stirred at a certain temperature and are subjected to constant-temperature treatment, so that the interaction of the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran can better play a role in modifying fiber aggregates, volcanic ash can be dispersedly adsorbed on fiber fillers, and the filling and adhesion of inner micro pores are facilitated, so that the concrete has good impermeability and anti-cracking performance.

Detailed Description

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

The information on the source of the raw materials used in the following examples and comparative examples is detailed in Table 1.

TABLE 1

Examples

Examples 1 to 3

The method comprises the following steps: mixing 2kg of maleic anhydride, 8kg of allyl polyoxyethylene ether, 1.55kg of polytetrahydrofuran, 3.2kg of ammonium persulfate and 1.68kg of polypropylene glycol, stirring at a rotating speed of 160r/min for 15min, heating to 80 ℃ at a heating rate of 5 ℃/min, keeping the temperature for 45min, and continuously keeping stirring in the constant temperature process to obtain a fiber modifier;

step two: weighing the fiber modifier in the amount shown in the table 2, cooling to 50 ℃, adding the fiber aggregate, stirring at a rotating speed of 120r/min for 20min, and keeping the constant temperature in the mixing process to obtain the improved fiber aggregate;

step three: the volcanic ash, the cement, the water, the coarse aggregate, the fine aggregate and the improved fiber aggregate are uniformly mixed to obtain the anti-permeability and anti-cracking concrete.

The fiber aggregate of examples 1-3 comprised polypropylene imitation steel fibers and sepiolite fibers, wherein the polypropylene imitation steel fibers accounted for 65% of the total weight of the fiber aggregate, the balance being sepiolite fibers, the polypropylene imitation steel fibers having a thickness of 1200D. PPG-200 was used as the polypropylene glycol in examples 1 to 3. The amounts (unit: kg) of the respective raw material components of examples 1 to 3 are specified in Table 2.

TABLE 2

	Example 1	Example 2	Example 3
				Cement	170	220	200
Coarse aggregate	640	680	660
				Fine aggregate	530	570	550
Water (W)	160	220	190
				Volcanic ash	30	60	45
Fiber aggregate	12	16	14
				Fiber modifier	7.0	8.5	8.3

Example 4

The difference from example 3 is that: in the first step, 1.9kg of maleic anhydride, 7.6kg of allyl polyoxyethylene ether, 1.45kg of polytetrahydrofuran, 3kg of ammonium persulfate and 1.64kg of polypropylene glycol are mixed to obtain the fiber modifier.

Example 5

The difference from example 3 is that: in the first step, 2.1kg of maleic anhydride, 8.4kg of allyl polyoxyethylene ether, 1.65kg of polytetrahydrofuran, 3.3kg of ammonium persulfate and 1.72kg of polypropylene glycol are mixed to obtain the fiber modifier.

Example 6

The difference from example 3 is that: in the first step, 1.7kg of maleic anhydride, 7.2kg of allyl polyoxyethylene ether, 1.3kg of polytetrahydrofuran, 2.6kg of ammonium persulfate and 1.5kg of polypropylene glycol are mixed to obtain the fiber modifier.

Example 7

The difference from example 3 is that: in the first step, 2.4kg of maleic anhydride, 9kg of allyl polyoxyethylene ether, 1.8kg of polytetrahydrofuran, 3.6kg of ammonium persulfate and 1.9kg of polypropylene glycol are mixed to obtain the fiber modifier.

Example 8

The difference from example 3 is that: PPG-600 is selected as the polypropylene glycol.

Example 9

The difference from example 3 is that: PPG-1000 is selected as polypropylene glycol.

Example 10

The difference from example 3 is that: 75% of the fiber aggregate in parts by weight is polypropylene steel-like fiber, and the balance is sepiolite fiber.

Example 11

The difference from example 3 is that: the fiber aggregate is polypropylene steel-like fiber.

Example 12

The difference from example 3 is that: the fiber aggregate is sepiolite fiber.

Example 13

The difference from example 3 is that: the thickness of the polypropylene imitation steel fiber is 1500D.

Example 14

The difference from example 3 is that: the fiber aggregate is polypropylene fine fiber.

Example 15

The difference from example 3 is that: and the constant temperature of the second step is 60 ℃, and the stirring time is 10 min. .

Example 16

The difference from example 3 is that: the constant temperature time of the first step is 30 min.

Examples 17 to 20

The difference from example 3 is that: the first constant temperature in the steps of examples 16 to 19 were 70 ℃ C., 75 ℃ C., 85 ℃ C., and 90 ℃ C., respectively.

Examples 21 to 22

The difference from example 3 is that: the first temperature rise rates of the steps of examples 20 to 21 were 8 ℃/min and 15 ℃/min, respectively.

Comparative example

Comparative example 1

The difference from example 3 is that: the fine aggregate with the same weight part replaces volcanic ash.

Comparative example 2

The difference from example 3 is that: replacing the fiber aggregate with the fine aggregate with the same weight part.

Comparative example 3

The difference from example 3 is that: the fine aggregate with the same weight part replaces the fiber modifier.

Comparative example 4

The difference from example 3 is that: in the first step, maleic anhydride is not added in the preparation of the fiber modifier.

Comparative example 5

The difference from example 3 is that: in the first step, allyl polyoxyethylene ether is not added in the preparation of the fiber modifier.

Comparative example 6

The difference from example 3 is that: in the first step, polytetrahydrofuran is not added in the preparation of the fiber modifier.

Comparative example 7

The difference from example 3 is that: the constant temperature in step one was 50 ℃.

Performance test

Experiment 1

The concrete samples prepared in the examples and the comparative examples were tested for the splitting tensile strength (unit: MPa) at 7d and 28d according to the Standard for testing mechanical Properties of ordinary concrete GB/T50081-2002.

Experiment 2

The average water penetration height (unit: mm) of the concrete test pieces prepared in each example and comparative example after curing for 28d was measured according to the test method Standard for Long-term Performance and durability of ordinary concrete GB/T50082-2009.

Experiment 3

Concrete test pieces prepared in each example and comparative example were tested for slump (unit: mm) according to Standard test method for ordinary concrete mixture Properties GB/T50080-2016.

The specific assay data for experiments 1-3 are detailed in tables 3-6

TABLE 3

According to comparison of detection data of the example 3 and the comparative examples 1 to 3 in the table 3, after the fiber aggregate is modified by the fiber modifier, the fiber aggregate is matched with volcanic ash to act on concrete, so that the moisture segregation condition of the concrete can be reduced, the slump of the concrete is reduced, the concrete has good construction performance, the cracking condition of the internal structure of the concrete is reduced, the structure of the concrete is more compact, the splitting tensile strength of the concrete is improved, the average water seepage height is reduced, and the concrete has excellent anti-permeability and anti-cracking performance.

TABLE 4

According to comparison of detection data of the example 3 and the comparative examples 4-6 in the table 4, maleic anhydride, allyl polyoxyethylene ether and polytetrahydrofuran generate mutual influence in the environment of ammonium persulfate and polypropylene glycol, and act on the fiber aggregate together to modify the fiber aggregate, so that the fiber aggregate is matched with volcanic ash in concrete, the concrete has good water retention performance, the hydration reaction of the concrete is performed stably, the internal cracking condition caused by the violent early hydration reaction of the concrete is reduced, and the impermeability and the anti-cracking performance of the concrete are improved.

According to the comparison of the detection data of the examples 3 to 7 in the table 4, the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol can generate better mutual influence in a specific mass ratio range, so that the modification effect on the fiber aggregate is better exerted.

TABLE 5

According to comparison of the detection data of the embodiment 3 and the embodiments 8 to 9 in table 5, the molecular weight of the polypropylene glycol is selected within a certain range, and the molecular weight can properly adjust the mutual dispersibility of the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran, so that the fiber modifier has a better modification effect on the fiber aggregate, and a certain auxiliary effect on improving the splitting tensile strength and the average water seepage height of the concrete is achieved.

According to the comparison of the detection data of the example 3 and the examples 10 to 14 in the table 5, the polypropylene steel-like fiber and the sepiolite fiber which are mixed in a certain proportion range are selected as the fiber aggregate, so that the compatibility of the fiber modifier and the fiber aggregate can be improved, and the better anti-permeability and anti-cracking effects can be exerted on concrete. In addition, the polypropylene imitation steel fiber selects proper fiber thickness, can be better mutually matched with the fiber modifier and the volcanic ash, and improves the impermeability and the anti-cracking performance of the concrete in a more balanced manner.

TABLE 6

According to comparison of detection data of the embodiment 3, the embodiments 16-20 and the comparative example 7 in the table 6, the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol are stirred and treated at constant temperature for a certain time within a certain temperature range, so that the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran can generate better mutual influence, and the effect of adsorbing volcanic ash on fiber aggregates is achieved more uniformly, so that the concrete has lower slump and water seepage height and higher tensile splitting strength, the anti-permeability and anti-cracking performance of the concrete is improved, and the construction requirements are better met.

According to comparison of the detection data of the embodiment 3 and the embodiments 21 to 22 in table 6, when the constant temperature treatment is performed on the maleic anhydride, the allyl polyoxyethylene ether, the polytetrahydrofuran, the ammonium persulfate and the polypropylene glycol at a certain temperature rise speed, the stability of the reaction process of the maleic anhydride, the allyl polyoxyethylene ether and the polytetrahydrofuran can be improved, the fiber modifier can exert a better effect, and the concrete can show better anti-permeability and anti-cracking performance.

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.