CN113816696A - A kind of ultra-high performance concrete based on internal curing of recycled fine aggregate and preparation method thereof - Google Patents

Abstract

Translated fromChinese

本发明公开了一种基于再生细集料内养护的超高性能混凝土及其制备方法。该超高性能混凝土按质量份数计，包括以下组分：普通硅酸盐水泥500～650份，粉煤灰100～150份，硅灰150～250份，空心玻璃微珠30～100份，再生细粉20～100份，再生细集料120～360份，细集料790～1030份，聚羧酸减水剂20～28份，水170～190份；其中再生细集料进行吸水饱和预处理；还包括钢纤维，按体积百分比计，钢纤维占超高性能混凝土的1.5～2.5％。所得超高性能混凝土有效降低了水化热和收缩，提高了强度，具有优异的力学性能、体积稳定性和耐久性，且制备方法和施工工艺简单，容易操作，具有实际推广应用价值。The invention discloses an ultra-high performance concrete based on internal curing of regenerated fine aggregates and a preparation method thereof. The ultra-high performance concrete includes the following components in parts by mass: 500-650 parts of ordinary Portland cement, 100-150 parts of fly ash, 150-250 parts of silica fume, 30-100 parts of hollow glass microspheres, 20 to 100 parts of regenerated fine powder, 120 to 360 parts of regenerated fine aggregate, 790 to 1030 parts of fine aggregate, 20 to 28 parts of polycarboxylate water reducing agent, and 170 to 190 parts of water; wherein the regenerated fine aggregate is saturated with water Pretreatment; also includes steel fibers, which account for 1.5 to 2.5% of the ultra-high performance concrete by volume percentage. The obtained ultra-high performance concrete effectively reduces hydration heat and shrinkage, improves strength, has excellent mechanical properties, volume stability and durability, and has simple preparation method and construction process, easy operation, and practical application value.

Description

Recycled fine aggregate internal curing-based ultrahigh-performance concrete and preparation method thereof

Technical Field

The invention belongs to the technical field of building material ultrahigh-strength concrete, and particularly relates to ultrahigh-performance concrete based on recycled fine aggregate internal curing and a preparation method thereof.

Background

Ultra-high performance concrete (UHPC for short) is a novel cement-based composite material with ultrahigh strength, high toughness, high durability and good volume stability. It usually adopts cementing materials (such as cement, silica fume, fly ash, mineral powder and the like), fine aggregates and steel fibers with different grain size grading to achieve closest packing under the ultra-low water-to-gel ratio (usually about 0.2), thereby preparing a novel cement-based material with excellent performance. The components and characteristics enable the size and the dead weight of the UHPC component to be obviously reduced, the UHPC component has a compact microstructure and extremely low porosity, shows excellent durability and can greatly prolong the service life of an engineering structure. However, because UHPC has a very low water-to-gel ratio, and its self-shrinkage value is usually several times or even an order of magnitude that of ordinary concrete, potential cracking problems ultimately reduce UHPC strength and durability.

With the large-scale urban infrastructure, the resources such as sand, cement and the like are greatly consumed; meanwhile, the old concrete buildings and engineering structures are dismantled and transformed, and the stacking amount of the waste concrete is increased year by year. In order to relieve the increasingly scarce condition of raw material resources of cement concrete and solve a series of environmental and social problems caused by the sharply increased waste concrete, the waste concrete is urgently needed to be subjected to building material recycling. The regenerated fine aggregate is prepared by cleaning, crushing, screening and washing waste concrete, and compared with the common natural fine aggregate river sand, the regenerated fine aggregate has the most prominent characteristic of high water absorption rate, and sometimes even can reach about 20%. The regenerated fine aggregate contains more old mortar blocks and mortar attached to the original fine aggregate, so that the regenerated fine aggregate has the characteristics of high porosity and high water absorption, and is very in line with the characteristics of concrete porous aggregate internal curing agents. The particle hardness of the regenerated fine aggregate is slightly lower than that of natural sandstone aggregate, but is much higher than that of the common lightweight internal curing materials such as ceramsite and the like, so that the regenerated fine aggregate is suitable for being used as an internal curing material of concrete, and the unique internal curing characteristic of the regenerated fine aggregate provides a brand new idea for the use of the regenerated aggregate. However, excessive amounts of recycled powder and adhesive mortar in the recycled aggregate reduce the workability and mechanical properties of the concrete, and direct application to ultra-high performance concrete can result in reduced concrete performance. How to design and apply the recycled aggregate to the ultra-high performance concrete and play a role in reducing shrinkage and improving strength at the same time to obtain the ultra-high performance concrete with excellent comprehensive performance has important environmental protection significance and economic value.

Disclosure of Invention

The invention aims to provide the ultrahigh-performance concrete based on the recycled fine aggregate as the internal curing aggregate and the preparation method thereof, which effectively reduce the hydration heat and the shrinkage of the ultrahigh-performance concrete, control the non-structural cracks of the ultrahigh-performance concrete, improve the strength of the ultrahigh-performance concrete, have the characteristics of excellent mechanical property, volume stability, durability and the like, have simple preparation method and construction process, are easy to operate and have practical popularization and application values.

In order to solve the technical problems, the invention adopts the following technical scheme:

the ultra-high performance concrete based on the internal curing of the recycled fine aggregate comprises the following components in parts by weight:

500-650 parts of ordinary portland cement, 100-150 parts of fly ash, 150-250 parts of silica fume, 30-100 parts of hollow glass beads, 20-100 parts of regenerated fine powder, 120-360 parts of regenerated fine aggregate, 790-1030 parts of fine aggregate, 20-28 parts of polycarboxylic acid water reducing agent and 170-190 parts of water; wherein the regenerated fine aggregate is subjected to water saturation pretreatment; the ultrahigh-performance concrete further comprises steel fibers, and the steel fibers account for 1.5-2.5% of the ultrahigh-performance concrete in percentage by volume.

And after the regenerated fine aggregate is subjected to water absorption saturation pretreatment, the water absorption amount in the regenerated fine aggregate is counted in the total water demand of the concrete.

According to the scheme, the ultra-high performance concrete refers to the concrete with the strength reaching 150MPa or above.

According to the scheme, the ordinary portland cement is PO 52.5-grade ordinary portland cement or PII 52.5-grade portland cement.

According to the scheme, the fly ash is I-grade fly ash or ultrafine fly ash floating beads.

According to the scheme, the silica fume is ultrafine silica fume, and the specific surface area is more than or equal to 18000m²Per kg, mean particle diameter < 5 μm, where SiO₂The content is more than or equal to 95 percent.

According to the scheme, the hollow glass beads are compounded by soda lime-borosilicate materials, and the compression strength of the hollow glass beads is>35MPa, apparent density>350kg/m³。

According to the scheme, the regenerated fine powder refers to the content of particles with the particle size of less than 0.075mm in the crushing process of waste concrete. Preferably, the particle size is 20 to 75 μm.

According to the scheme, the regenerated fine aggregate is waste concrete, and is sand in a II area with the fineness of 2.2-2.8 after being cleaned, crushed, screened and cleaned.

According to the scheme, the particle size of the regenerated fine aggregate is 0.15-0.3mm, 0.3-0.6mm or 0.6-1.18mm, and the regenerated fine aggregate is graded or continuously graded. Wherein the apparent density and the saturated water absorption of the 0.15-0.3mm regenerated fine aggregate are 2328kg/m³And 8.3 percent of the recycled fine aggregate with the particle size of 0.3-0.6mm, the apparent density and the saturated water absorption of 2304kg/m³13.1 percent, and the apparent density and the saturated water absorption of the 0.6-1.18mm regenerated fine aggregate are 2277kg/m³And 11.3%.

According to the scheme, the fine aggregate is one or a mixture of two of natural river sand and machine-made sand, and the fineness modulus is 2.3-2.9.

According to the scheme, the steel fiber is cold-drawn copper-plated micro-wire steel fiber, and the diameter of the micro-wire steel fiber is more than or equal to 0.2 mm; the length is more than or equal to 13mm, and the tensile strength is more than or equal to 3200 MPa.

According to the scheme, the polycarboxylate superplasticizer is a polycarboxylate superplasticizer, the solid content is more than or equal to 40%, and the water reduction rate is more than or equal to 35%.

According to the scheme, the water is tap water, municipal filtered water or drinking water, and meets the water standard for concrete buildings.

The preparation method of the ultra-high performance concrete based on the internal curing of the recycled fine aggregate comprises the following steps:

s1: soaking the regenerated fine aggregate in water until the water absorption is saturated, taking out the saturated regenerated fine aggregate from the water, blowing the saturated regenerated fine aggregate to the surface to dry to obtain the saturated regenerated fine aggregate, and calculating the saturated water absorption capacity m of the saturated regenerated fine aggregate₁；

S2: taking ordinary portland cement, fly ash, silica fume, glass beads, water-saturated regenerated fine aggregate and fine aggregate, stirring the raw materials for 90-120 s by using a rotary stirrer, and uniformly mixing to obtain uniform dry blend;

s3: mixing the polycarboxylate water reducer and water uniformly, adding the dry mixture, and stirring for 240-260 s to obtain uniformly mixed slurry, wherein the water is used in an amount of: total water consumption m-saturated water absorption m of regenerated fine aggregate₁；

S4: adding steel fibers into the mixed slurry while stirring, and uniformly stirring for 80-100 s;

s5: and pouring the uniformly stirred mixture into a mold, covering and curing the mixture by using a film at normal temperature, and curing the mixture at normal temperature to obtain the recycled fine aggregate-based internal curing ultrahigh-performance concrete after molding and hardening.

The invention has the following beneficial effects:

1. the invention provides a low-shrinkage ultrahigh-performance concrete prepared from recycled fine aggregate, aiming at the special high water absorption rate of the recycled fine aggregateThe recycled fine aggregate saturated with water is used as an internal curing material and is compounded with natural aggregate, so that the shrinkage of concrete can be effectively reduced, moisture can be continuously released, and the hydration reaction of a cementing material is supplied, so that the internal curing effect is achieved, and the continuous development of the strength of a concrete matrix is promoted; but the strength of the super high performance concrete doped with the regenerated fine aggregate is reduced due to the surface microcrack and the porous characteristic of the regenerated fine aggregate, so that the regenerated fine powder can play a filling role by replacing cement with a certain proportion, and meanwhile, CaCO in the fine powder₃For C in cement₃S and C₃The hydration reaction of A has the promotion function, the generated hydration product can form crystal nucleus, the content of C-S-H gel of the hydration product is increased, the microstructure of the cement-based material is improved, and the strength of the concrete is improved; and the components such as the fly ash, the silica fume, the hollow glass beads, the fine aggregate, the water reducing agent and the like are matched, so that the hydration heat and the shrinkage of the ultrahigh-performance concrete are effectively reduced, the non-structural crack of the ultrahigh-performance concrete is controlled, the strength of the ultrahigh-performance concrete is improved, the cost is obviously reduced on the basis of improving the comprehensive performance of the ultrahigh-performance concrete, the recycling of waste resources is realized, and the method has important economic value and environmental protection significance.

2. The regenerated fine aggregate can be uniformly dispersed in the ultrahigh-performance concrete, the internal curing effect on the ultrahigh-performance concrete is more uniform, the influence of the ion concentration of cement slurry is not easily caused, and the better curing effect is achieved; in addition, the internal curing area of the regenerated fine aggregate is large, so that the self-shrinkage of the ultra-high performance concrete is greatly reduced; the ultra-high performance concrete provided by the invention has the characteristics of excellent mechanical property, volume stability, durability and the like, and the preparation method and the construction process are simple, easy to operate and have practical popularization and application values.

3. Furthermore, one graded or continuous graded water-saturated recycled fine aggregate with the grain size of 0.15-0.3mm, 0.3-0.6mm or 0.6-1.18mm is selected, the water absorption rate is high, and the obtained ultra-high performance concrete has excellent comprehensive performance.

Detailed Description

The invention will be further described with reference to specific embodiments:

in the following examples, the specific parameter indexes of the raw materials used are as follows:

the ordinary Portland cement is PO 52.5-grade ordinary Portland cement with the specific surface area of 400m²/kg。

The fly ash is I-grade fly ash, and the loss on ignition is 1.18 percent.

The silica fume is superfine silica fume, and the specific surface area is more than or equal to 18000m²Per kg, mean particle diameter < 5 μm, where SiO₂The content is more than or equal to 95 percent.

The hollow glass beads are compounded by soda lime-borosilicate material components and have compressive strength>35MPa, apparent density>350kg/m³。

The regenerated fine powder is the content of particles with the particle size of less than 0.075mm in the crushing process of waste concrete, and the particle size of the regenerated fine powder is 20-75 microns.

The regenerated fine aggregate is waste concrete and is cleaned, crushed, sieved and washed, and the produced sand in a zone II with the fineness of 2.2-2.8 has three gradations of 0.15-0.3mm, 0.3-0.6mm or 0.6-1.18mm, wherein the apparent density and the saturated water absorption of the regenerated fine aggregate with the fineness of 0.15-0.3mm are 2328kg/m³And 8.3 percent of the recycled fine aggregate with the particle size of 0.3-0.6mm, the apparent density and the saturated water absorption of 2304kg/m³13.1 percent, and the apparent density and the saturated water absorption of the 0.6-1.18mm regenerated fine aggregate are 2277kg/m³And 11.3%.

The fine aggregate is natural river sand, and the fineness modulus is 2.3-2.9.

Cold-drawing the copper-plated micro-wire steel fiber, wherein the diameter of the micro-wire steel fiber is more than or equal to 0.2 mm; the length is more than or equal to 13mm, and the tensile strength is more than or equal to 3200 MPa.

The solid content of the polycarboxylic acid high-efficiency water reducing agent is more than or equal to 40 percent, and the water reducing rate is more than or equal to 35 percent.

The water is tap water.

The preparation method of the ultra-high performance concrete based on the regenerated fine aggregate as the internal curing aggregate in the following embodiments of the invention comprises the following steps:

1) soaking the weighed regenerated fine aggregate in a water tank filled with tap water until the water is saturated, taking out the saturated regenerated fine aggregate from the water, blowing the regenerated fine aggregate to the surface dry by a blower, and calculating the saturated water absorption capacitym₁；

2) Firstly, respectively stirring the raw materials of ordinary portland cement, fly ash, silica fume, glass beads, stone powder, saturated regenerated fine aggregate and fine aggregate for 90 seconds by using a rotary stirrer, and uniformly mixing to obtain uniform dry blend;

3) mixing a polycarboxylic acid water reducing agent and water (the total water consumption m-the saturated water absorption m of the regenerated fine aggregate)₁) Stirring uniformly, slowly adding the dry mixture, and stirring for 240s to obtain uniformly mixed slurry;

4) adding steel fibers into the mixed slurry while stirring, and uniformly stirring for 90 s;

5) and pouring the uniformly stirred mixture into a mold, covering and curing the mixture by using a film at normal temperature, and curing the mixture at normal temperature to obtain the recycled fine aggregate-based internal curing ultrahigh-performance concrete after molding and hardening.

Comparative example 1

Providing an ultra-high performance concrete which is used as a blank group and comprises the following components in parts by weight:

600 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 100 parts of hollow glass beads, 1150 parts of fine aggregate, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.5 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Comparative example 2

The provided ultra-high performance concrete is added with regenerated fine powder and comprises the following components in parts by weight:

600 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 50 parts of hollow glass beads, 50 parts of regenerated fine powder, 1150 parts of fine aggregate, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.5 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Comparative example 3

The provided ultra-high performance concrete is added with regenerated fine aggregate, and comprises the following components in parts by weight:

600 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 50 parts of hollow glass beads, 240 parts of 0.015-1.18 mm continuous graded regenerated fine aggregate, 910 parts of fine aggregate, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.5 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Comparative example 4

The super-high performance concrete is added with Super Absorbent Polymer (SAP), and comprises the following components in parts by mass:

550 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 100 parts of hollow glass beads, 20 parts of regenerated fine powder, 30 parts of super absorbent resin, 1150 parts of fine aggregate, 1.5 parts of steel fiber based on the total volume of concrete, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.5 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Example 1

The provided ultra-high performance concrete based on the recycled fine aggregate as the internal curing aggregate comprises the following components in parts by weight:

600 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 50 parts of hollow glass beads, 50 parts of regenerated fine powder, 240 parts of 0.15-1.18mm continuous graded regenerated fine aggregate, 910 parts of fine aggregate, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water.

The concrete also comprises steel fibers, and the steel fibers account for 1.5 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Example 2

The provided ultra-high performance concrete based on the recycled fine aggregate as the internal curing aggregate comprises the following components in parts by weight:

550 parts of ordinary portland cement, 150 parts of fly ash, 200 parts of silica fume, 50 parts of hollow glass beads, 50 parts of regenerated fine powder, 360 parts of 0.15-0.3 mm-graded regenerated fine aggregate, 790 parts of fine aggregate, 28 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.8 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Example 3

The provided ultra-high performance concrete based on the recycled fine aggregate as the internal curing aggregate comprises the following components in parts by weight:

580 parts of ordinary portland cement, 120 parts of fly ash, 200 parts of silica fume, 50 parts of hollow glass beads, 50 parts of regenerated fine powder, 240 parts of 0.3-0.6 mm-graded regenerated fine aggregate, 910 parts of fine aggregate, 25 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 1.8 percent of the total volume of the ultra-high performance concrete in percentage by volume.

Example 4

The provided ultra-high performance concrete based on the recycled fine aggregate as the internal curing aggregate comprises the following components in parts by weight:

550 parts of ordinary portland cement, 150 parts of fly ash, 150 parts of silica fume, 100 parts of hollow glass beads, 50 parts of regenerated fine powder, 360 parts of 0.6-1.18 mm-graded regenerated fine aggregate, 790 parts of fine aggregate, 28 parts of polycarboxylic acid water reducing agent and 180 parts of water;

the concrete also comprises steel fibers, and the steel fibers account for 2.0 percent of the total volume of the ultra-high performance concrete in percentage by volume.

The ultra-high performance concrete obtained in examples 1 to 4 and comparative examples 1 to 4 were subjected to performance tests, and the results are shown in Table 1.

TABLE 1 results of performance test of ultra high Performance concrete obtained in examples 1 to 4 and comparative examples 1 to 4

As can be seen from Table 1, the strength of the ultra-high performance concrete obtained in examples 1 to 4 of the present invention was improved to a certain extent while the self-shrinkage was significantly reduced as compared with comparative examples 1 to 4, when the recycled fine powder and the recycled fine aggregate were simultaneously added to the ultra-high performance concrete. The results show that the invention can effectively improve the strength and the shrinkage reducing performance of the obtained ultra-high performance concrete, can effectively ensure the working performance such as fluidity and the like, and has wide applicability.

The above examples are merely preferred examples and are not intended to limit the embodiments of the present invention. In addition to the above embodiments, the present invention has other embodiments. All technical solutions formed by adopting equivalent substitutions or equivalent transformations fall within the protection scope of the claims of the present invention.

Claims (10)

Translated fromChinese

1.一种基于再生细集料内养护的超高性能混凝土，其特征在于，按质量份数计，包括以下组分：1. a kind of ultra-high performance concrete based on the inner curing of regenerated fine aggregate, is characterized in that, by mass fraction, comprises the following components:普通硅酸盐水泥500～650份，粉煤灰100～150份，硅灰150～250份，空心玻璃微珠30～100份，再生细粉20～100份，再生细集料120～360份，细集料790～1030份，聚羧酸减水剂20～28份，水170～190份；其中：Ordinary Portland cement 500-650 parts, fly ash 100-150 parts, silica fume 150-250 parts, hollow glass beads 30-100 parts, recycled fine powder 20-100 parts, recycled fine aggregate 120-360 parts , 790-1030 parts of fine aggregate, 20-28 parts of polycarboxylate water reducing agent, and 170-190 parts of water; of which:所述再生细集料进行吸水饱和预处理；The regenerated fine aggregate is subjected to water absorption saturation pretreatment;所述超高性能混凝土还包括钢纤维，按体积百分比计，所述钢纤维占超高性能混凝土的1.5～2.5％。The ultra-high performance concrete also includes steel fibers, and the steel fibers account for 1.5-2.5% of the ultra-high performance concrete in terms of volume percentage.2.根据权利要求1所述的超高性能混凝土，其特征在于，所述的普通硅酸盐水泥为PO52.5级普通硅酸盐水泥或PII52.5级硅酸盐水泥。2 . The ultra-high performance concrete according to claim 1 , wherein the ordinary Portland cement is PO52.5 grade ordinary Portland cement or PII52.5 grade Portland cement. 3 .3.根据权利要求1所述的超高性能混凝土，其特征在于，所述的粉煤灰为I级粉煤灰或超细粉煤灰漂珠；所述的硅灰为超细硅灰，比表面积≥18000m²/kg，平均粒径＜5μm，其中SiO₂含量≥95％。3. ultra-high performance concrete according to claim 1, is characterized in that, described fly ash is Class I fly ash or ultra-fine fly ash float beads; Described silica fume is ultra-fine silica fume, The specific surface area is ≥18000m² /kg, the average particle size is less than 5μm, and the SiO₂ content is ≥95%.4.根据权利要求1所述的超高性能混凝土，其特征在于，所述的空心玻璃微珠为碱石灰-硼硅酸盐材料成分复配而成，其抗压强度>35MPa，表观密度>350kg/m³。4. ultra-high performance concrete according to claim 1, is characterized in that, described hollow glass microspheres are compounded by soda lime-borosilicate material components, and its compressive strength＞35MPa, apparent density >350kg/m³ .5.根据权利要求1所述的超高性能混凝土，其特征在于，所述的再生细粉是指废弃混凝土破碎过程中粒径小于0.075mm的颗粒含量。5 . The ultra-high performance concrete according to claim 1 , wherein the regenerated fine powder refers to the content of particles with a particle size smaller than 0.075 mm in the crushing process of the waste concrete. 6 .6.根据权利要求1所述的超高性能混凝土，其特征在于，所述的再生细集料为废弃混凝土进行清理、破碎、筛分和清洗，所制成的细度2.2～2.8的II区中砂。6 . The ultra-high performance concrete according to claim 1 , wherein the regenerated fine aggregate is waste concrete to be cleaned, crushed, screened and cleaned, and the resulting fineness of 2.2-2.8 is in zone II. 7 . Medium sand.7.根据权利要求1所述的超高性能混凝土，其特征在于，所述的再生细集料粒径为0.15～0.3mm，0.3～0.6mm或0.6～1.18mm一种级配或连续级配。7 . The ultra-high performance concrete according to claim 1 , wherein the particle size of the recycled fine aggregate is 0.15-0.3mm, 0.3-0.6mm or 0.6-1.18mm in a gradation or continuous gradation. 8 . .8.根据权利要求1所述的超高性能混凝土，其特征在于，所述的细集料为天然河砂、机制砂的一种或两种混合物，细度模数为2.3～2.9。8 . The ultra-high performance concrete according to claim 1 , wherein the fine aggregate is one or two mixtures of natural river sand and machine-made sand, and the fineness modulus is 2.3-2.9. 9 .9.根据权利要求1所述的超高性能混凝土，其特征在于，所述的钢纤维为冷拉镀铜微丝钢纤维，微丝钢纤维直径≥0.2mm；长度≥13mm，抗拉强度≥3200MPa；所述的聚羧酸减水剂为聚羧酸高效减水剂，固含量≥40％，减水率≥35％。9 . The ultra-high performance concrete according to claim 1 , wherein the steel fibers are cold-drawn copper-coated micro-wire steel fibers, the diameter of the micro-wire steel fibers is ≥ 0.2 mm; the length is ≥ 13 mm, and the tensile strength is ≥ 10 . 3200MPa; the polycarboxylate superplasticizer is a polycarboxylate superplasticizer, with a solid content of ≥40% and a water reduction rate of ≥35%.10.一种权利要求1-9任一项所述的基于再生细集料内养护的超高性能混凝土的制备方法，其特征在于，包括以下步骤：10. the preparation method of the ultra-high performance concrete based on the inner curing of regenerated fine aggregate described in any one of claim 1-9, is characterized in that, comprises the following steps:S1：将再生细集料浸泡在水中，直至吸水饱和，将饱和再生细集料从水中取出，吹至表面面干得饱水再生细集料，并计算其饱和吸水量m₁；S1: soak the regenerated fine aggregate in water until the water absorption is saturated, take out the saturated regenerated fine aggregate from the water, blow it to the surface to dry the saturated regenerated fine aggregate, and calculate its saturated water absorption m₁ ;S2：取普通硅酸盐水泥、粉煤灰、硅灰、玻璃微珠、饱水再生细集料、细集料，利用旋转式搅拌机将上述原材料进行搅拌90～120s，混合均匀，得到均匀干混料；S2: Take ordinary Portland cement, fly ash, silica fume, glass microbeads, water-saturated regenerated fine aggregates, and fine aggregates, and use a rotary mixer to stir the above raw materials for 90-120 s, and mix them evenly to obtain uniform dry mix;S3：将聚羧酸减水剂与水进行搅拌均匀，加入S2所得干混料，搅拌240～260s得到均匀混合浆体，其中水的用量为：总用水量m-再生细集料饱和吸水量m₁；S3: Stir the polycarboxylate water-reducing agent and water evenly, add the dry mixture obtained from S2, and stir for 240-260s to obtain a uniformly mixed slurry, wherein the amount of water is: total water consumption m-saturated water absorption of regenerated fine aggregates m₁ ;S4：将S3所得混合浆体中一边搅拌一边加入钢纤维，均匀搅拌80～100s；S4: adding steel fibers to the mixed slurry obtained in S3 while stirring, and stirring evenly for 80-100 s;S5：将搅拌均匀的拌合物灌入模具中，使用薄膜覆盖养护常温养护，待成型硬化后即可得到基于再生细集料内养护超高性能混凝土。S5: Pour the well-stirred mixture into the mold, cover it with a film for curing at room temperature, and after forming and hardening, the inner curing ultra-high performance concrete based on recycled fine aggregate can be obtained.