A kind of minimum inflation low heat silicate cementTechnical field
The invention belongs to building material technical field, particularly a kind of minimum inflation low heat silicate cement.
Background technology
Silicate cement series general is at present developed by the silicate cement of invention in 1824, is with the raw material such as Wingdale, clay, designs suitable rate value and composition, and through " two mills one burn ", processes forms, and is hydraulic cementing materials the most large at present.Over nearly 200 years, chemical composition and the mineral composition of silicate cement do not change substantially, and the technical progress of Cement industry is mainly reflected in production technique.
For a long time, silicate cement widespread use with the advantage such as stable performance, mature production technology, but its hydration heat in mass concrete, concrete for hydraulic structure hydration process and water requirement higher, drying shrinkage is comparatively large, easily causes concrete cracking.
Low-heat portland cement is with the low feature of its hydration heat, the crack that can effectively prevent thermal stress from producing in mass concrete, but in engineer applied, for ensureing that concrete volume stability that it configures cement expansive material used is at present difficult to play suitable swell increment, data shows that a kind of high magnesium low-heat portland cement clinker aggregate has certain volumetric expansion performance, but it reaches microdilatancy effect by content of MgO in controlling and adjustment cement clinker, production technology difficulty is high, case history proves poor stability, is difficult to large-scale popularization application.Because the MgO swelling agent mixed outward is different with the firing condition of the MgO component that cement includes, the bulking effect both causing in mass concrete is different.Tracking Data presents good delayed microswelling characteristic, and longterm expansion distortion always tends towards stability, and main swell increment occurs in d in the length of time 7 ~ 90.And during this period of time, significant hypothermal after temperature rise rapidly occurs mass concrete just shrinks the period, so expansion is now shunk for the temperature drop compensating mass concrete and is highly profitable, and can accomplish all or most of conventional temperature control measure cancelling mass concrete.And the MgO that cement includes, only exceed the part ability hydration swelling of solid melt, and the expansion that this ratio of expansion externally mixing MgO causes is much slow, expansion effect is poor, and the phase of expansion is grown and is difficult to control, and the compensating action shunk mass concrete temperature drop is little.In addition, use externally mixing MgO swelling agent mode, according to the final condition of different sites and stress compensation needs, by firing condition and the volume of adjustment MgO swelling agent, the time of origin, steady time, rate of expansion, swell increment etc. of concrete expansion distortion can be adjusted neatly.Therefore, use externally mixing MgO bang swollen dose of mode, higher than use containing Mg0 manufacture of cement Mg0 concrete, more can play the superiority of MgO concrete technology.Therefore make a kind of low-heat portland cement with microdilatancy performance be necessary very much by mixing Mg0 method outward.
Summary of the invention
The object of this invention is to provide a kind of there is low-heat micro-expansion, technique is simple, expansion character is stablized, energy-saving and emission-reduction, minimum inflation low heat silicate cement with low cost, not only can overcome the problem that Conventional Portland series cement hydration heat is high, easy to crack, also help environmental protection and resource circulation utilization.
Technical scheme of the present invention is:
A kind of minimum inflation low heat silicate cement, is characterized in that: be mixed by low-heat portland cement clinker aggregate, gypsum, light-burned MgO, slag, wherein the weight percent of each component is as follows:
Low-heat portland cement clinker aggregate 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 calcareous raw material3content≤3%.
Described calcareous raw material is one or more the arbitrary combination in Wingdale, low-grade limestone or high magnesium lime stone.
Described clayey raw material is one or more the arbitrary combination in clay, red mud, coal gangue, mine tailing and industrial residue.
Described correction material is iron powder or sulfate slag class ferro-controlling raw material.
Described correction material is silico-regulating material, and concrete is quartzite, or silica, or yellow ground, or red sand.
Described low-heat portland cement clinker aggregate, 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 Standard) and other trace quantity mineral (this trace quantity mineral requires for conventional).
Described gypsum is one or more the arbitrary combination in the plaster of paris, mixed gypsum or artificial gypsum.
In described light-burned MgO, size range is MgO >=97% of 0 ~ 0.125 μm.
Described light-burned MgO is made up of higher-grade magnesite stone ore naturally cooling after 750 ~ 1050 DEG C of calcinings, calcination time 15 ~ 90min; Also can produce by dolomite mineral, serpentine, smelting lightweight magnesium alloy slag starting material.
Described slag is lectric furnace slag and converter slag, and its specific surface area is 290 ~ 450m2/ kg.
Know-why of the present invention is: form brucite Mg (OH) after utilizing the CaO aquation in light-burned MgO and slag respectively2absorb water with Ca (OH) 2 and produce volumetric expansion, macroscopically make cement have micro-expansibility; Utilize the high C in this cement2s content reduces the hydration heat of cement; Utilizing slag to obtain grinding aid makes reduction cement wear away, and makes up that early stage MgO hydration swelling amount is difficult to meet gelling material volume stability because low-heat portland cement extent of hydration is low simultaneously.
Compared with prior art, its beneficial effect is as follows in the present invention:
The features such as cement provided by the invention has microdilatancy, low-heat, water requirement is low, later strength enhancement rate is high, longterm strength is stable, are very suitable for the construction of the mass concretes such as dam, cushion cap, extra large work engineering.
Embodiment
embodiment 1
Magnesite is calcined 60min at 800 DEG C, and levigate mistake 0.125 μm sieve after naturally cooling, slag is ground to specific surface area 300m2/ kg, according to following proportioning:
Low-heat portland cement clinker aggregate 85%
Gypsum 5%
Light-burned MgO 2%
Slag 6%
Levigate after mixing, make fineness be less than 12%, be mixed with minimum inflation low heat silicate cement.The minimum inflation low heat silicate cement chemical composition prepared and mineral composition as shown in table 1.
embodiment 2
Magnesite is calcined 60min at 850 DEG C, and levigate mistake 0.125 μm sieve after naturally cooling, slag is ground to specific surface area 390m2/ kg is low-heat portland cement clinker aggregate 85% according to proportioning, gypsum 5%, light-burned MgO2%, slag 6%.Levigate after mixing, make fineness be less than 12%, be mixed with minimum inflation low heat silicate cement.
embodiment 3
Magnesite is calcined 60min at 950 DEG C, and levigate mistake 0.125 μm sieve after naturally cooling, slag is ground to specific surface area 420m2/ kg, according to following proportioning:
Low-heat portland cement clinker aggregate 85%
Gypsum 5%
Light-burned MgO 2%
Slag 6%
Levigate after mixing, make fineness be less than 12%, be mixed with minimum inflation low heat silicate cement.
embodiment 4
Magnesite is calcined 60min at 850 DEG C, and levigate mistake 0.125 μm sieve after naturally cooling, slag is ground to specific surface area 390m2/ kg, according to following proportioning:
Low-heat portland cement clinker aggregate 85%
Gypsum 5%
Light-burned MgO 4%
Slag 10%
Levigate after mixing, make fineness be less than 12%, be mixed with minimum inflation low heat silicate cement.
embodiment 5
Magnesite is calcined 60min at 850 DEG C, and levigate mistake 0.125 μm sieve after naturally cooling, slag is ground to specific surface area 390m2/ kg, according to following proportioning:
Low-heat portland cement clinker aggregate 85%
Gypsum 5%
Light-burned MgO 5%
Slag 15%
Levigate after mixing, make fineness be less than 12%, be mixed with minimum inflation low heat silicate cement.
The expansion character experimental result (rate of expansion experiment is carried out according to JC313-82 expansive cement rate of expansion experimental technique) of each minimum inflation low heat silicate cement that above-described embodiment obtains is as shown in table 3.