CN102173700A - Minimum inflation low heat silicate cement - Google Patents

Abstract

The invention discloses minimum inflation low heat silicate cement. The cement comprises the following components in percentage by weight: 75 to 95 percent of low heat silicate clinker, 1 to 10 percent of gypsum, 0.01 to 6 percent of lightly-burnt MgO, and 5 to 15 percent of steel slag. The minimum inflation low heat silicate cement can effectively reduce early concrete plastic cracking and temperature stress cracking generated by later hydrating adiabatic temperature rise, caused by adverse construction and maintenance conditions when the concrete is constructed. The prepared concrete has the advantages of high flowing performance, small dry shrinkage, little temperature contraction joint and the like, and can be applied in the fields of mass concrete, hydraulic concrete, high performance concrete engineering and the like which have high requirement on anti-cracking performance.

Description

A kind of microdilatancy low-heat portland cement

Technical field

The invention belongs to building material technical field, particularly a kind of microdilatancy low-heat portland cement.

Background technology

At present general silicate cement series is developed by the silicate cement of invention in 1824, is with raw materials such as Wingdale, clays, design suitable rate value and composition, and processes forms, and is the most large present hydraulic cementing materials through " two mills, one burning ".Over nearly 200 years, the chemical ingredients of silicate cement and mineral composition do not have to change substantially, and the technical progress of Cement industry is mainly reflected on the production technique.

For a long time, silicate cement is with advantages such as stable performance, mature production technology and widespread use, but its hydration heat and water requirement in mass concrete, concrete for hydraulic structure hydration process is higher, and drying shrinkage is bigger, easily causes concrete cracking.

Low-heat portland cement is with the low characteristics of its hydration heat, in mass concrete, can effectively prevent the crack that thermal stress produces, but in engineering is used, for the present used cement expansive material of the concrete volume stability that guarantees its configuration is difficult to bring into play suitable swell increment, data shows that a kind of high magnesium low-heat portland cement grog has certain volumetric expansion performance, but it is to reach the microdilatancy effect by MgO content in control and the adjustment cement clinker, production technology difficulty height, case history proof poor stability is difficult to large-scale popularization and uses.Because the MgO swelling agent of mixing outward is different with the firing condition of the MgO component that cement includes, and causes both bulking effect differences in mass concrete.The externally mixing MgO concrete presents good delay microdilatancy characteristic, and long-term dilatational strain always tends towards stability, and main swell increment occurs in d in the length of times 7～90.And during this period of time, the significant hypothermal that takes place after the temperature rise rapidly of mass concrete shrinks the period just, so the expansion of this moment is highly profitable for the temperature drop contraction of compensation mass concrete, can accomplish traditional temperature control measures of whole or most of cancellation mass concretes.And the MgO that cement includes has only the part that surpasses solid melt could hydration swelling, and the expansion that causes of this ratio of expansion externally mixing MgO slowly many, expansion effect is poor, the phase of expansion is long and be difficult to control, the compensating action that the mass concrete temperature drop is shunk is little.In addition, use externally mixing MgO swelling agent mode, can be according to the final condition and the stress compensation needs of different sites, by adjusting the firing condition and the volume of MgO swelling agent, adjust the time of origin, steady time, rate of expansion, swell increment of concrete dilatational strain etc. neatly.Therefore, use externally mixing MgO bang bloated agent mode,, more can bring into play the superiority of MgO concrete technology than using height to contain Mg0 manufacture of cement Mg0 concrete.Therefore make a kind of low-heat portland cement and be necessary very much by mixing the Mg0 method outward with microdilatancy performance.

Summary of the invention

The purpose of this invention is to provide a kind ofly have low-heat micro-expansion, technology is simple, expansion character is stable, energy-saving and emission-reduction, microdilatancy low-heat portland cement with low cost, not only can overcome traditional silicate series hydration heat of cement height, problem easy to crack, also help environmental protection and resource circulation utilization.

Technical scheme of the present invention is:

A kind of microdilatancy low-heat portland cement is characterized in that: be mixed and made into by low-heat portland cement grog, gypsum, light-burned MgO, slag, wherein the weight percent of each component is as follows:

Low-heat portland cement grog 75～85%;

Gypsum 1～10%;

Light-burned MgO 0.01～6%;

Slag 5～20%.

The raw-material weight per-cent of described low-heat silicate grog is:

Calcareous raw material 65～90%

Raw clay 5～30%

Correction material 5～20%

Wherein, the MgCO in the calcareous raw material₃Content≤3%.

Described calcareous raw material is one or more the arbitrary combination in Wingdale, low-grade limestone or the high magnesium lime stone.

Described clayey raw material is one or more the arbitrary combination in clay, red mud, coal gangue, mine tailing and the industrial residue.

Described correction material is iron powder or sulfate slag class ferro-controlling raw material.

Described correction material is siliceous correction material, and concrete is quartzite, perhaps silica, perhaps yellow ground, perhaps red sand.

Described low-heat portland cement grog, the weight percent of its mineral composition is:

C₂S 40～80%

MgO 0.1～2%

All the other are C₃S, C₄These two kinds of component percentages of AF(are that GB requires) and other trace quantity mineral (this trace quantity mineral requires for commonly used).

Described gypsum is one or more the arbitrary combination in the plaster of paris, mixed gypsum or the artificial gypsum.

Among the described light-burned MgO, size range is MgO 〉=97% of 0～0.125 μ m.

Described light-burned MgO makes calcination time 15～90min by higher-grade magnesite stone ore naturally cooling after 750～1050 ℃ of calcinings; Also can be by producing in dolomite mineral, serpentine, the smelting lightweight magnesium alloy slag starting material.

Described slag is electric furnace oxidation sludge and converter slag, and its specific surface area is 290～450m²/ kg.

Know-why of the present invention is: form brucite Mg (OH) respectively after utilizing the CaO aquation in light-burned MgO and the slag₂And Ca (OH) 2 suction generation volumetric expansions, make cement have micro-expansibility on the macroscopic view; Utilize the high C in this cement₂S content reduces the hydration heat of cement; Utilize slag to obtain grinding aid and make and reduce the cement abrasion, remedy simultaneously that early stage MgO hydration swelling amount is difficult to satisfy the gelling material volume stability because the low-heat portland cement extent of hydration is low.

The present invention compared with prior art, its beneficial effect is as follows:

Characteristics such as cement provided by the invention has that microdilatancy, low-heat, water requirement are low, later strength enhancement rate height, longterm strength are stable are very suitable for the construction of mass concretes such as dam, cushion cap, maritime works's engineering.

Embodiment

Embodiment 1

Magnesite is calcined 60min down at 800 ℃, levigate mistake 0.125 μ m sieve behind the naturally cooling, slag is ground to specific surface area 300m²/ kg, according to following proportioning:

Low-heat portland cement grog 85%

Gypsum 5%

Light-burned MgO 2%

Slag 6%

Levigate behind the mixing, make fineness less than 12%, be mixed with the microdilatancy low-heat portland cement.The microdilatancy low-heat portland cement chemical ingredients and the mineral composition that prepare are as shown in table 1.

Embodiment 2

Magnesite is calcined 60min down at 850 ℃, levigate mistake 0.125 μ m sieve behind the naturally cooling, slag is ground to specific surface area 390m²/ kg is a low-heat portland cement grog 85% according to proportioning, gypsum 5%, light-burned MgO2%, slag 6%.Levigate behind the mixing, make fineness less than 12%, be mixed with the microdilatancy low-heat portland cement.

Embodiment 3

Magnesite is calcined 60min down at 950 ℃, levigate mistake 0.125 μ m sieve behind the naturally cooling, slag is ground to specific surface area 420m²/ kg, according to following proportioning:

Low-heat portland cement grog 85%

Gypsum 5%

Light-burned MgO 2%

Slag 6%

Levigate behind the mixing, make fineness less than 12%, be mixed with the microdilatancy low-heat portland cement.

Embodiment 4

Magnesite is calcined 60min down at 850 ℃, levigate mistake 0.125 μ m sieve behind the naturally cooling, slag is ground to specific surface area 390m²/ kg, according to following proportioning:

Low-heat portland cement grog 85%

Gypsum 5%

Light-burned MgO 4%

Slag 10%

Levigate behind the mixing, make fineness less than 12%, be mixed with the microdilatancy low-heat portland cement.

Embodiment 5

Magnesite is calcined 60min down at 850 ℃, levigate mistake 0.125 μ m sieve behind the naturally cooling, slag is ground to specific surface area 390m²/ kg, according to following proportioning:

Low-heat portland cement grog 85%

Gypsum 5%

Light-burned MgO 5%

Slag 15%

Levigate behind the mixing, make fineness less than 12%, be mixed with the microdilatancy low-heat portland cement.

The expansion character experimental result of each microdilatancy low-heat portland cement that the foregoing description makes (the rate of expansion experiment is carried out according to JC313-82 expansive cement rate of expansion experimental technique) is as shown in table 3.

Claims (10)

1. microdilatancy low-heat portland cement, it is characterized in that: be mixed and made into by low-heat portland cement grog, gypsum, light-burned MgO, slag, wherein the weight percent of each component is as follows:

Low-heat portland cement grog 75～85%;

Gypsum 1～10%;

Light-burned MgO 0.01～6%;

Slag 5～20%.

2. a kind of microdilatancy low-heat portland cement according to claim 1 is characterized in that: the raw-material weight per-cent of described low-heat silicate grog is:

Calcareous raw material 65～90%

Raw clay 5～30%

Correction material 5～20%

Wherein, the MgCO in the calcareous raw material₃Content≤3%.

3. a kind of microdilatancy low-heat portland cement according to claim 2 is characterized in that: described calcareous raw material is one or more the arbitrary combination in Wingdale, low-grade limestone or the high magnesium lime stone.

4. a kind of microdilatancy low-heat portland cement according to claim 2 is characterized in that: described clayey raw material is one or more the arbitrary combination in clay, red mud, coal gangue, mine tailing and the industrial residue.

5. a kind of microdilatancy low-heat portland cement according to claim 2 is characterized in that: described correction material is iron powder or sulfate slag class ferro-controlling raw material.

6. a kind of microdilatancy low-heat portland cement according to claim 2 is characterized in that: described correction material is siliceous correction material, and concrete is quartzite, perhaps silica, perhaps yellow ground, perhaps red sand.

7. a kind of microdilatancy low-heat portland cement according to claim 1 is characterized in that: described low-heat portland cement grog, and the weight percent of its mineral composition is:

C₂S 40～80%

MgO 0.1～2%

All the other are C₃S, C₄AF and other trace quantity mineral.

8. a kind of microdilatancy low-heat portland cement according to claim 1 is characterized in that: described gypsum is one or more the arbitrary combination in the plaster of paris, mixed gypsum or the artificial gypsum.

9. a kind of microdilatancy low-heat portland cement according to claim 1 is characterized in that: among the described light-burned MgO, size range is MgO 〉=97% of 0～0.125 μ m.

10. a kind of microdilatancy low-heat portland cement according to claim 1 is characterized in that: described slag is the mixture of electric furnace oxidation sludge or converter slag or electric furnace oxidation sludge and converter slag, and its specific surface area is 290～450m²/ kg.