阅读说明：本技术 一种变质岩骨料高强混凝土及其制备方法 (Metamorphic rock aggregate high-strength concrete and preparation method thereof ) 是由 班录江 林喜华 袁棕 赵士豪 李曾光 陈洋 许志永 王军 于 2021-08-15 设计创作，主要内容包括：本发明涉及一种变质岩骨料高强混凝土及其制备方法,混凝土各组分质量比如下：水泥：早强型辅助胶凝材料：易流型辅助胶凝材料：变质岩机制砂：变质岩碎石：水：高效复合外加剂：AZK辅助剂＝310～350：50～75：135～150：786～896：896～960：156～161：7.3～8.6：2.1～3.1,本发明通过系列技术的协同使用,有效抑制变质岩的碱骨料反应,实现变质岩骨料制备混凝土的高流态化、高强化。为变质岩在工程中的大体量使用提供依据。(The invention relates to metamorphic rock aggregate high-strength concrete and a preparation method thereof, wherein the concrete comprises the following components in percentage by mass: cement: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: and (3) an AZK adjuvant 310-350: 50-75: 135-150 parts by weight: 786 to 896: 896-960: 156-161: 7.3-8.6: 2.1-3.1, the alkali aggregate reaction of metamorphic rock is effectively inhibited through the synergistic use of a series of technologies, and the high fluidization and high reinforcement of the concrete prepared from the metamorphic rock aggregate are realized. Provide the basis for the large-scale use of metamorphic rocks in engineering.)

1. The metamorphic rock aggregate high-strength concrete is characterized by comprising the following components in percentage by mass: cement: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: and (3) an AZK adjuvant 310-350: 50-75: 135-150 parts by weight: 786 to 896: 896-960: 156-161: 7.3-8.6: 2.1 to 3.1.

2. The concrete according to claim 1, wherein the cement is a P.O42.5 or P.O52.5 cement conforming to GB175, and the alkali content is less than or equal to 0.6%.

3. The concrete of claim 1, wherein the early strength type auxiliary cementitious material is a mixture of silica fume, granulated blast furnace slag powder and metakaolin ultrafine powder, the 45-micron screen residue is less than or equal to 5.0%, the fluidity ratio is more than or equal to 96%, the 7d activity index is more than or equal to 115%, and the 28d activity index is more than or equal to 120%.

4. The concrete according to claim 1, wherein the easily flowing auxiliary cementing material is a mixture of fly ash, superfine waste glass powder, phosphorus slag powder and glass beads, and has an activity of not less than 75% in 7 days, an activity of not less than 85% in 28 days and an activity of not less than 110% in 60 days.

5. The concrete according to claim 1, wherein the metamorphic rock mechanical sand has an MB value of 1.0 or less, a fineness modulus of 2.8-3.3, a 80 μm sieve bottom of 5.0 or less, a water content of 0.5 or less, and a crush value of 5.0 or less.

6. The concrete as claimed in claim 1, wherein the metamorphic rock broken stone has a continuous gradation of 4.75-26.5mm, a crushing value of 8.0% or less, a pin-shaped content of 8% or less, a water content of 0.5% or less, and a metamorphic rock axial compression strength of 100MPa or more.

7. The concrete according to claim 1, wherein the high-efficiency composite admixture is a low-alkali-content admixture, the water-reducing rate is more than or equal to 30.0%, and the gas content of the concrete is 1.0-2.0%.

8. The concrete according to claim 1, wherein the AZK adjuvant is a mixture of thioaluminate, water glass and calcium formate, and the mass percentage is 15-45: 10-40: 35-65 parts of solid powder.

9. The concrete according to claim 8, wherein the mass percent of the AZK adjuvant is 15-20: 20-35: 50-60 parts of a mixture of sulphoaluminate, water glass and calcium formate.

10. The preparation method of the metamorphic rock aggregate high-strength concrete is characterized by comprising the following steps:

the method comprises the following steps: weighing the following components in percentage by mass: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: an AZK adjuvant;

step two: weighing the following cement: early strength type supplementary cementitious material: uniformly mixing the easy-flowing auxiliary cementing material and an AZK auxiliary agent to obtain a mixed glue material;

step three: and uniformly mixing the weighed water and the high-efficiency composite additive to obtain a mixed solution, placing the metamorphic rock machine-made sand, the metamorphic rock broken stone and the mixed rubber material in a stirrer, stirring for 1-2min, adding the mixed solution, and stirring for 2-3min to obtain the metamorphic rock aggregate high-strength concrete.

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to metamorphic rock aggregate high-strength concrete and a preparation method thereof.

Background

Metamorphic rocks are widely distributed in China, account for more than 1/6 of the total area of the whole area in Guizhou, and the metamorphic rocks cannot be widely applied to concrete due to potential alkali activity. In Guizhou areas, due to the restriction of geographical environment and natural resources, only local rock aggregate and machine-made sand can be adopted to prepare concrete. With the promotion of township and village livening in the western part of China, a large amount of infrastructure projects such as municipal administration, highways, high-speed railways and the like are comprehensively constructed, the demand of sandstone aggregates is huge, and local materials are required from the aspects of economy, environment and the like. The lack of natural resources of the metamorphic rock aggregate is more prominent in metamorphic rock areas, and the adoption of metamorphic aggregate for preparing concrete is imperative, so that research and development of metamorphic rock aggregate high-strength concrete applied to engineering construction are urgently needed. However, the above-mentioned problems of alkali aggregate reaction also arise, for example, the crush value is high and it is difficult to produce high-strength concrete.

Disclosure of Invention

The application provides metamorphic rock aggregate high-strength concrete and a preparation method thereof, and aims to solve the problems of alkali aggregate reaction and difficulty in preparing high-strength concrete in the existing concrete prepared from metamorphic rock aggregate.

According to one aspect of the application, the metamorphic rock aggregate high-strength concrete and the preparation method thereof are provided, and the metamorphic rock aggregate high-strength concrete comprises the following components in percentage by mass: cement: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: and (3) an AZK adjuvant 310-350: 50-75: 135-150 parts by weight: 786 to 896: 896-960: 156-161: 7.3-8.6: 2.1 to 3.1.

The cement is P.O42.5 or P.O52.5 cement conforming to GB175, and the alkali content is less than or equal to 0.6 percent.

Furthermore, the early-strength auxiliary cementing material is a mixture of silica fume, granulated blast furnace slag powder and metakaolin ultrafine powder, the 45-micron screen residue is less than or equal to 5.0%, the fluidity ratio is more than or equal to 96%, the 7-day activity index is more than or equal to 115%, and the 28-day activity index is more than or equal to 120%.

Furthermore, the easy-flowing auxiliary cementing material is a mixture of fly ash, superfine waste glass powder, phosphorus slag powder and glass beads, and the activity of the easy-flowing auxiliary cementing material in 7 days is more than or equal to 75 percent, the activity of the easy-flowing auxiliary cementing material in 28 days is more than or equal to 85 percent, and the activity of the easy-flowing auxiliary cementing material in 60 days is more than or equal to 110 percent.

Furthermore, the metamorphic rock machine-made sand has the MB value less than or equal to 1.0, the fineness modulus of 2.8-3.3, the sieve bottom with the particle size of 80 mu m less than or equal to 5.0%, the water content less than or equal to 0.5% and the crushing value less than or equal to 5.0%.

Furthermore, the metamorphic rock broken stone has continuous gradation of 4.75-26.5mm, the crushing value is less than or equal to 8.0 percent, the needle sheet content is less than or equal to 8 percent, the water content is less than or equal to 0.5 percent, and the axial compression strength of the metamorphic rock is more than or equal to 100 Mpa.

Furthermore, the high-efficiency composite additive is a low-alkali-content additive, the water reduction rate is more than or equal to 30.0 percent, and the gas content of the concrete is 1.0 to 2.0 percent

Further, the AZK auxiliary agent is a mixture of sulphoaluminate, water glass and calcium formate, and the mass percentage is 15-45: 10-40: 35-65 parts of solid powder.

Further, the mass percentage of the AZK auxiliary agent is 15-20: 20-35: 50-60 parts of a mixture of sulphoaluminate, water glass and calcium formate.

A preparation method of metamorphic rock aggregate high-strength concrete comprises the following steps:

the method comprises the following steps: weighing the following components in percentage by mass: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: an AZK adjuvant;

step two: weighing the following cement: early strength type supplementary cementitious material: uniformly mixing the easy-flowing auxiliary cementing material and an AZK auxiliary agent to obtain a mixed glue material;

step three: and uniformly mixing the weighed water and the high-efficiency composite additive to obtain a mixed solution, placing the metamorphic rock machine-made sand, the metamorphic rock broken stone and the mixed rubber material in a stirrer, stirring for 1-2min, adding the mixed solution, and stirring for 2-3min to obtain the metamorphic rock aggregate high-strength concrete.

The water meets the regulations of the Water for concrete Standard (JGJ 63).

The action mechanism of the invention is as follows:

firstly, the performance of a concrete cementing material system is improved through the creative composite synergistic application of an early-strength auxiliary cementing material and a flowable type auxiliary cementing material. In particular to the method for improving the concrete strength by improving the activity of a concrete cementing system by utilizing the high activity of an early-strength cementing material. The easy-flowing type assists the ball effect of the cementing material, changes the friction mechanism among particles, changes the sliding motion among aggregates into rolling, reduces the friction resistance among particles, and improves the fluidity of concrete.

And secondly, by applying the high-doping-amount early-strength and easy-flowing auxiliary cementing material, the alkali content of the cementing material per unit mass is reduced, and microparticles in the cementing material are mutually filled, so that the compactness is further improved, the permeability is reduced, the activity of alkali ions is greatly reduced, and the alkali-aggregate reaction is effectively inhibited.

Thirdly, the metamorphic rock machine-made sand and crushed stone are optimized, on one hand, aggregate gradation is controlled, the closest packing of a concrete aggregate system is realized by utilizing an aggregate closest packing technology, the filling of slurry is reduced, and the workability of concrete is improved; and on the other hand, the aggregate is preferably selected to ensure the aggregate, so that the skeleton effect of the concrete macadam is favorably enhanced, and the strength of the concrete is improved.

And fourthly, the AZK auxiliary agent is used to accelerate the hydration of cement and promote the secondary hydration of the early-strength and easy-flowing auxiliary cementing material. On the one hand, Al₂(SO₄)₃And rapid dissolution of gypsum to make SO₄ ^2-Increased concentration of Ca (OH) in solution₂、Al₂O₃The reaction is carried out to generate needle column-shaped AFt (fully called high-sulfur hydrated calcium sulphoaluminate). Na (Na)₂O.nSiO₂And Ca (OH)₂Fast reaction to produce (n-1) SiO₂Colloid and CaSiO₂. The formate ion in HCOO-is capable of forming AHt and the analogous form of AFm (full name: calcium sulfoaluminate monohydrate)₃A·3Ca(HCOO)₂·30H₂O，C₃A·Ca(HCOO)·10H₂0, etc.), greatly accelerates cement hydration. In addition, due to HCOO^-Ion diffusion velocity ratio Ca²⁺Ions are fast and thus can penetrate to C₃S and C₂Hydration layer of S, accelerated Ca (OH)₂Precipitation of calcium silicate and decomposition of calcium silicate. HCOO^-The ions can further bind the silicon atoms to OH through chemical action^-Reacting to crosslink the adjacent silicate population, promoting the formation of C-S-H gel and improving the hardening strength of the cement. While the reaction product produces (n-1) SiO₂Colloid, CaSiO₂Mutually condensed and filled with AFt, AFm and the like to form a compact system structure and improve the structural strength. On the other hand, cement hydration generates a large amount of Ca (OH)₂In alkaline environment, the active SiO in the early-strength and easy-flowing auxiliary cementing material is excited₂Dissociation of (3), active SiO₂And Ca (OH)₂C-S-H gel is generated by reaction, gaps are further filled, the structure is improved, and the strength is improved. And simultaneously, the reaction of the metamorphic rock active ingredient and Ca (OH)2 is inhibited. The early-strength and easy-flowing auxiliary cementing material which is not hydrated in the early stage and alkali generated by later-stage cement hydration generate hydration reaction again, and the alkali aggregate reaction of metamorphic rock is further inhibited.

The invention has the beneficial effects that: through the synergistic use of a series of technologies, the alkali aggregate reaction of metamorphic rock is effectively inhibited, and the high fluidization and high reinforcement of concrete prepared from metamorphic rock aggregate are realized. Provide the basis for the large-scale use of metamorphic rocks in engineering.

Detailed Description

The technical solution of the present invention is further described in detail by the following examples, which are illustrative but not limiting of the present invention.

A preparation method of metamorphic rock aggregate high-strength concrete comprises the following steps:

the method comprises the following steps: weighing the following components in percentage by mass: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: an AZK adjuvant;

step two: weighing the following cement: early strength type supplementary cementitious material: uniformly mixing the easy-flowing auxiliary cementing material and an AZK auxiliary agent to obtain a mixed glue material;

step three: and uniformly mixing the weighed water and the high-efficiency composite additive to obtain a mixed solution, placing the metamorphic rock machine-made sand, the metamorphic rock broken stone and the mixed rubber material in a stirrer, stirring for 1-2min, adding the mixed solution, and stirring for 2-3min to obtain the metamorphic rock aggregate high-strength concrete.

The ingredient mass ratios of examples 1 to 5 are as follows:

the cement in examples 1-5 was followed: early strength type supplementary cementitious material: easy-flowing type auxiliary cementing material: metamorphic rock machine-made sand: metamorphic rock breaking: water: high-efficiency composite additive: and weighing the components of the AZK auxiliary agent in proportion, and carrying out the rest steps according to a test method for inhibiting the activity of the alkali-silicic acid reaction of the aggregate in GB/T50733-2011 appendix A.

The mass percentages of the components of the AZK auxiliary agents of the examples 1 to 5 are as follows:

	thioaluminate salts	Water glass	Calcium formate
				Example 1	45	30	35
Example 2	20	40	40
				Example 3	15	35	50
Example 4	20	20	60
				Example 5	25	10	65

The concrete performance criteria for examples 1-5 are as follows:

as is apparent from the above table, in examples 1 to 5, the slump expansion of the concrete is greater than 200mm, the slump expansion is greater than 560mm, and the workability meets the construction requirements. Meanwhile, the emptying time of the concrete discharged from the machine and poured into the barrel is within 5s, and the fluidity and cohesiveness of the concrete are excellent. The standard curing strength of 7d is 48.5-58.7MPa, the 28d strength is 62.1-68.7MPa, and the 60d strength is 67.4-75.8MPa, which can meet the high strength requirement of above C60. Meanwhile, the later strength of the concrete is continuously increased, and the strength of the concrete is improved. The expansion rates of the 14d quick mortar rods are all less than 0.03 percent, which shows that the invention effectively inhibits the alkali-silicic acid reaction of the aggregate.

The foregoing is a more detailed description of the invention in connection with specific preferred embodiments and it is not intended that the invention be limited to these specific details. For those skilled in the art to which the invention pertains, several simple deductions or substitutions can be made without departing from the spirit of the invention, and all shall be considered as belonging to the protection scope of the invention.