CN1092747A

CN1092747A - High-efficiency concrete expansion admixture and manufacture method thereof

Info

Publication number: CN1092747A
Application number: CN 94100423
Authority: CN
Inventors: 李乃珍
Original assignee: SPECIAL CEMENT PLANT OF SHIJIAZHUANG CITY
Current assignee: SPECIAL CEMENT PLANT OF SHIJIAZHUANG CITY
Priority date: 1994-01-28
Filing date: 1994-01-28
Publication date: 1994-09-28
Anticipated expiration: 2014-01-28
Also published as: CN1040741C

Abstract

The invention provides a kind of high-efficiency concrete expansion admixture and method for making thereof, it is characterized in that by 20-40% sulphoaluminate cement clinker or 15-35% calcium aluminate clinker, 35-60% anhydrite, 6-60% unslaked lime, the common grinding of 5-10% natural alumstone forms.The advantage of this swelling agent is: 1. rate of expansion height; 2. add-on is few; 3. cost is low; 4. help keeping cement alkalinity, reduce strength of cement loss and steel bar corrosion; 5. alkalinity is lower than 0.5%, can avoid or alleviate the concrete alkali; 6. technology is simple, easy to implement.

Description

High-efficiency concrete expansion admixture and manufacture method thereof

The invention belongs to concrete filler component or technical field of concrete additives.

Available coagulation soil expansion agent kind is more both at home and abroad, and is main listed as table 1.All there is weak point in these swelling agents.For example, NO1 and NO2 use the calcining of high-quality alumina to form, and contain the calcium sulphoaluminate grog of a large amount of fcao, the energy consumption height, and the cost height, the rotary kiln burning techniques is still immature, and NO5 uses waste slag of fluorine gypsum, should not be used for water works; Except that NO.1 and NO.2, the alunite that all mixes more than 10% is made main component, and the alkali content of introducing is unfavorable for suppressing the concrete alkali more than 0.7%; Each swelling agent all need rely on silicate cement hydration product C a(OH) 2 participation could form enough ettringite, therefore, speed of expansion slowly, poor efficiency, often need to increase the swelling agent consumption and just can play the compensate for shrinkage effect.NO9 and NO10 are with Ca(OH) 2 be expansion sources, should not be used for water works.

Task of the present invention provides that a kind of speed of expansion is very fast, rate of expansion is higher, efficient, low alkali content and the cement expansive material that has small expansion mid-term again, and its production technique is simple, easy to implement, cost is lower.

The present invention is achieved in that a kind of high-efficiency concrete expansion admixture and method for making thereof, it is characterized in that, by the sulphoaluminate cement clinker of 20-40% or the calcium aluminate clinker of 15-30%, the anhydrite of 35-60% or through the dihydrate gypsum of 400-500 ℃ of processed, the unslaked lime of 5-20%, the common grinding of the natural alumstone of 5-10% forms, and general specific surface area is greater than 250m ²/ kg gets final product.Above-mentioned sulphoaluminate cement clinker is with commercially available or make with rotary kiln or shaft kiln calcination, because of its cost lower.

Reaction mechanism of the present invention is represented with following chemical equation:

2. formula reaches formula and 3. shows, forms the needed CaO of ettringite C3A3CaSO4H32, and mainly the unslaked lime that is contained by swelling agent self provides, and no longer relies on the hydrated product Ca(OH of C3S with C2S basically) 2.By the Al203 in the commercially available sulphoaluminate cement clinker, can make big of phase or all form ettringite short, give full play to the expansion function; The Al203 that is provided by alunite then forms ettringite in mid-term, form the required theoretical amount of ettringite because the unslaked lime that adds is lower than, so CaO is not neither expansion sources can cause stability bad yet.

Advantage of the present invention is tangible:

(1) form the necessary CaO of ettringite because this swelling agent self has contained, the expansion function can obtain higher utilization in early days.

(2) owing to form the hydrated product Ca(OH that ettringite no longer consumes C3S and C2S basically) 2, be beneficial to the maintenance silicate cement, particularly the basicity of slag cement, trass cement, pulverized fuel ash cement for reducing the concrete strength loss, prevents that steel bar corrosion is significant.

(3) because this swelling agent self only contains the alunite below 10%, when guaranteeing the small expansion that produces mid-term, make K2O+Na20＜0.5%, be beneficial to and suppress the concrete alkali.

(4) only use milling equipment owing to make this swelling agent, need not calcine, so it is technology is simple, easy to implement; Because available merchant's stone raw material: sulphoaluminate cement clinker, so cost is reduced greatly.

(5) compare with the listed NO1 of the table 1 close, NO2 with this swelling agent, because with cheap unslaked lime and commercially available sulphoaluminate cement clinker, equivalence has replaced the special calcium sulphoaluminate grog that technical difficulty is big, unit-hour output is low, energy consumption is high, pollution is heavy, and the swelling agent production cost is reduced more than 50-60 unit/t.

(6) by Japanese J1S A6202-1980 or the standard test of Chinese JC476-92 cement expansive material, product performance reach and are higher than the level of standard code.Especially rate of expansion is higher, and consumption is less.

(7) use this swelling agent 6-10% equivalent to replace that cement can prepare expansive concrete, 11-13% equivalent replaces cement and can prepare big dilatation seams concrete, can form the self-stress value of 0.2-0.1MPa, receive the effect of anti-crack and anti-seepage, 18-23% equivalent replaces cement can prepare self-stressing concrete, and consumption is few, freight charges are low, construction investment is economized.

Table 2 is production examples.Table 3 has been listed used starting material and swelling agent Chemical Composition among the embodiment 1, swelling agent proportioning; Table 4 has been listed the swelling agent standard test performance under different curing conditions, swelling agent specific surface area 400m/kg, 1: 30 presetting period, final setting time 2: 20; ' table 5 listed C28, the Sb concrete determination data with the preparation of this swelling agent.

Remarks: the used reference of table 1 is as follows:

(1) Building technology, 1978, NO147, Japan.

(2) Chinese patent, CN85107101A.

(3) Chinese patent, 88102924.6.

(4) Chinese patent, 89108124.0.

(5) Chinese patent, 91110609.X.

(6) Chinese patent, 92105187.5.

(7) composite expanding agent technical evaluation certificate, 1987.

(8) alumite plumping agent technical evaluation certificate, 1980.

(9) You Baokun etc., " swelling agent and alkali-aggregate reaction ", 1992.

Table 2:

Table 3

Item is not	LoSS	SiO ₂	AL ₂O ₃	Fe ₂O ₃	TiO ₂	CaO	MgO
								Sulphoaluminate cement clinker		10.13	32.30	2.50	1.26	43.34	1.12
Anhydrite	9.86	1.29	0.18	0.03		37.68	1.58
								Alunite	7.04 crystal water	55.13	16.34	1.67	0.58	0.36	0.01
Unslaked lime	9.03	2.23	0.86	0.23		84.38	2.89
								Swelling agent	6.58	9.22	11.42	0.96	0.44	40.32	1.42

Table 3 is continuous

Item is not	SO ₃	K ₂O	Na ₂O	Σ	Proportioning %
						Sulphoaluminate cement clinker	9.25			99.90	30.0
Anhydrite	49.05			99.67	50.0
						Alunite	14.70	3.89	0.41	99.72	10.0
Unslaked lime				99.62	10.0
						Swelling agent	28.78	0.39	0.04	99.87

Table 5

Item is not	3d	7d	14d	28d	360d	Remarks
							Limited expansion rate %	0.011	0.014	0.018	0.033	0.045	Replace cement
Ultimate compression strength MPa		27.9	33.1	35.3	49.9	Rate 10%

Claims

1, a kind of high-efficiency concrete expansion admixture and method for making thereof, it is characterized in that, by the sulphoaluminate cement clinker of 20-40% or the calcium aluminate clinker of 15-35%, the anhydrite of 35-60% or through the dihydrate gypsum of 400-500 ℃ of processed, the unslaked lime of 5-20%, the common grinding of the natural alumstone of 5-10% forms.

2, high-efficiency concrete expansion admixture according to claim 1 and method for making thereof is characterized in that used sulphoaluminate cement clinker is commercially available or makes with rotary kiln or shaft kiln calcination.