阅读说明：本技术 一种磷酸镁水泥-硫铝酸盐水泥混凝土及其制备方法 (magnesium phosphate cement-sulphoaluminate cement concrete and preparation method thereof ) 是由 董琦 李云涛 李龙刚 吕培培 王宁宁 张宗兰 谭凯龙 张国华 水红林 于 2019-10-30 设计创作，主要内容包括：本发明提出一种用于抢修抢建的磷酸镁水泥-硫铝酸盐水泥混凝土及其制备方法,该混凝土按重量百分比由以下原料组成：硫铝酸盐水泥10～20％、氧化镁16～36％、磷酸二氢钾6.4～13.5％、硼砂0～2.0％、集料12～22.5％、中砂2.4～5.4％、钢纤维和聚丙烯纤维1.6～5.4％、温度为-10℃～-5℃的含磷酸盐冰水6～10％。本发明通过引入硫铝酸盐水泥、减少硼砂含量和加入连续级配石灰岩碎石和钢纤维及聚丙烯纤维,制备磷酸镁水泥-硫铝酸盐水泥混凝土,具有凝结硬化快、早中后期强度高、良好的韧性、耐磨性、抗冲击性和耐高温性能等特点,能够满足应急、战时等紧急情况下的公路、机场、桥梁、发射平台等设施的抢修抢建。(The invention provides a magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction and a preparation method thereof, wherein the concrete comprises the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃. The magnesium phosphate cement-sulphoaluminate cement concrete prepared by introducing sulphoaluminate cement, reducing borax content and adding continuous graded limestone macadam, steel fiber and polypropylene fiber has the characteristics of quick setting and hardening, high early, middle and later strength, good toughness, wear resistance, impact resistance, high temperature resistance and the like, and can meet the emergency repair and rush construction of facilities such as highways, airports, bridges, launching platforms and the like under emergency, wartime and other emergency situations.)

1. The magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction is characterized by comprising the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃.

2. The concrete according to claim 1, wherein the sulphoaluminate cement is 42.5 grade and has a specific surface area of 300-500 m²Per kg, the passing rate of a 45-micron negative pressure sieve is 83 percent.

3. The concrete according to claim 1, wherein the magnesium oxide has a chemical composition of less than 5% of calcium oxide and a specific surface area of 2200 to 2800cm²/g。

4. the concrete of claim 1, wherein the monopotassium phosphate and borax are 97% pure.

5. The concrete according to claim 1, wherein the aggregate is 4.7-27 mm continuous graded limestone macadam.

6. The concrete according to claim 1, wherein the medium sand fineness modulus is 2.0 to 3.0.

7. The concrete of claim 1, wherein the steel fibers have an aspect ratio of 30 and a density of 7.90g/cm³。

8. A method for preparing concrete according to any one of claims 1 to 7, comprising the steps of:

S1, preparing the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃;

S2, sequentially adding sulphoaluminate cement, magnesium oxide, potassium dihydrogen phosphate, borax, medium sand, aggregate, steel fibers and polypropylene fibers, and uniformly stirring;

And S3, adding phosphate-containing ice water and rapidly stirring to obtain the magnesium phosphate cement-sulphoaluminate cement concrete.

9. The method of claim 8, wherein in the step S3, the phosphate-containing ice water is added and rapidly stirred for 3 minutes.

Technical Field

The invention belongs to the technical field of building materials, and particularly relates to magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction and a preparation method thereof.

Background

Magnesium phosphate cement (magnesium-phosphate cement) is a novel cementing material which takes phosphate as a binding phase and is generated by acid-base reaction of dead-burned magnesium oxide, phosphate, a retarder and the like according to a certain proportion. Wherein, the magnesium oxide is prepared by calcining magnesite at a high temperature of 1400-1600 ℃, and the phosphate mainly provides an acid environment and phosphate ions for hydration reaction. The magnesium phosphate cement has the characteristics of rapid hardening, early strength, wide environmental adaptability and the like, and is mainly applied to the fields of rush repair and rush construction, rapid repair, military engineering and the like. The early setting and hardening of the magnesium phosphate cement are too fast, the setting time is mainly adjusted by borax at present, but the middle and later strength of the cement concrete is influenced, so that the construction difficulty of the magnesium phosphate cement-based material is large. Meanwhile, magnesium phosphate cement is more concentrated in a form of cement paste or mortar, no external agents such as coarse aggregates and admixture are used, hydration temperature is high, stability, working performance and frost resistance of the magnesium phosphate cement are poor, large-area rapid construction difficulty is high, and emergency repair and rush construction of military facilities such as highways, airports, launching platforms and the like under the new-period battlefield condition are difficult to meet.

Disclosure of Invention

Technical problem to be solved

The invention provides a magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction and a preparation method thereof, aiming at solving the technical problems of improving setting and hardening and controlling early, middle and later strength and various performances.

(II) technical scheme

in order to solve the technical problems, the invention provides a magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction, which comprises the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃.

Furthermore, the sulphoaluminate cement is 42.5 grade, and the specific surface area is 300-500 m²Per kg, the passing rate of a 45-micron negative pressure sieve is 83 percent.

Furthermore, the content of calcium oxide in the chemical components of magnesium oxide is less than 5%, and the specific surface area is 2200-2800 cm²/g。

Further, the purity of the potassium dihydrogen phosphate and the borax is 97%.

Furthermore, the aggregate is 4.7-27 mm continuous graded limestone macadam.

Furthermore, the fineness modulus of the medium sand is 2.0-3.0.

Further, the steel fiber had an aspect ratio of 30 and a density of 7.90g/cm³。

In addition, the invention also provides a preparation method of the concrete, which comprises the following steps:

S1, preparing the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃;

S2, sequentially adding sulphoaluminate cement, magnesium oxide, potassium dihydrogen phosphate, borax, medium sand, aggregate, steel fibers and polypropylene fibers, and uniformly stirring;

And S3, adding phosphate-containing ice water and rapidly stirring to obtain the magnesium phosphate cement-sulphoaluminate cement concrete.

Further, in step S3, phosphate ice water was added and stirred rapidly for 3 minutes.

(III) advantageous effects

the invention provides a magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction and a preparation method thereof, wherein the concrete comprises the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃.

The magnesium phosphate cement-sulphoaluminate cement concrete prepared by introducing sulphoaluminate cement, reducing borax content and adding continuous graded limestone macadam, steel fiber and polypropylene fiber has the characteristics of quick setting and hardening, high early, middle and later strength, good toughness, wear resistance, impact resistance, high temperature resistance and the like, and can meet the emergency repair and rush construction of facilities such as highways, airports, bridges, launching platforms and the like under emergency, wartime and other emergency situations.

The concrete of the invention has the following characteristics:

(1) The sulphoaluminate cement and the magnesium phosphate cement are compounded, so that the setting speed and the strength can be accelerated, and the sulphoaluminate cement has better high-temperature resistance and fluidity.

(2) because of low borax content, the magnesium phosphate concrete has fast setting and hardening speed and high early strength, and meets the requirements of rush repair and rush construction in engineering implementation.

(3) The phosphate-containing ice water with the temperature of-10 ℃ to-5 ℃ is used for stirring, so that the hydration temperature can be reduced, and the stability of the composite magnesium phosphate concrete can be improved.

(4) The continuous graded limestone broken stone, the steel fiber and the polypropylene fiber are added, so that the strength and the stability of the composite magnesium phosphate concrete are better.

(5) The potassium dihydrogen phosphate is used, ammonia gas is not generated in the stirring process, and adverse effects on the environment and human bodies are not generated.

(6) The setting time is 1-10 minutes, and the emergency repair and rush construction under the emergency condition are met.

(7) The magnesium phosphate cement-sulphoaluminate cement concrete mainly forms strength through acid-base reaction, the strength development is rapid, the early strength is high, the critical strength (3.5MPa) of the concrete which is allowed to be frozen can be rapidly reached and exceeded, and the construction can be carried out in a low-temperature cold region. The compression strength of 15-25 MPa can be formed in about 1h, and the traffic of 30-50 t equipment vehicles can be met.

(8) The hydration product of the material is mainly magnesium phosphate salt, has no calcium hydroxide, can not generate sulfate corrosion damage of common portland cement concrete, and has better sulfate corrosion resistance and seawater corrosion resistance.

(9) The invention does not need to specially process the raw materials, the maintenance can adopt natural maintenance in the air, the adopted equipment is common concrete equipment, the preparation method, the process and the required equipment are simple, and the emergency repair and the rush construction under emergency, battle and other emergency conditions are met.

Detailed Description

In order to make the objects, contents and advantages of the present invention clearer, the following detailed description of the embodiments of the present invention will be given in conjunction with examples.

The embodiment provides a magnesium phosphate cement-sulphoaluminate cement concrete for rush repair and rush construction, which comprises the following raw materials in percentage by weight: 10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers, and 6-10% of phosphate-containing ice water serving as mixing water at the temperature of-10 ℃ to-5 ℃.

in the embodiment, the sulphoaluminate cement is 42.5 grade, and the specific surface area is 300-500 m²Per kg, the passing rate of a 45-micron negative pressure sieve is 83 percent; the content of calcium oxide in the chemical components of the magnesium oxide is less than 5 percent, and the specific surface area is 2200-2800 cm²(ii)/g; the purity of the potassium dihydrogen phosphate and the borax is 97 percent; the aggregate is 4.7-27 mm continuous graded limestone macadam; the fineness modulus of the medium sand is 2.0-3.0; the length-diameter ratio of the steel fiber is 30, and the density is 7.90g/cm³。

The preparation method of the concrete comprises the following steps:

S1, preparing the following raw materials in percentage by weight:

10-20% of sulphoaluminate cement, 16-36% of magnesium oxide, 6.4-13.5% of potassium dihydrogen phosphate, 0-2.0% of borax, 12-22.5% of aggregate, 2.4-5.4% of medium sand, 1.6-5.4% of steel fibers and polypropylene fibers and 6-10% of phosphate-containing ice water at the temperature of-10 ℃ to-5 ℃;

S2, sequentially adding sulphoaluminate cement, magnesium oxide, potassium dihydrogen phosphate, borax, medium sand, aggregate, steel fibers and polypropylene fibers, and uniformly stirring;

And S3, adding phosphate ice water and rapidly stirring for 3 minutes to obtain the magnesium phosphate cement-sulphoaluminate cement concrete.