CN103713116B - A kind of method evaluating high MgO cement stability - Google Patents
A kind of method evaluating high MgO cement stability Download PDFInfo
- Publication number
- CN103713116B CN103713116B CN201310718641.6A CN201310718641A CN103713116B CN 103713116 B CN103713116 B CN 103713116B CN 201310718641 A CN201310718641 A CN 201310718641A CN 103713116 B CN103713116 B CN 103713116B
- Authority
- CN
- China
- Prior art keywords
- cement
- examination body
- stability
- mgo
- high mgo
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Abstract
The invention discloses a kind of method evaluating high MgO cement stability, including: step 1, high MgO cement to be measured, iso standard sand, water are mixed according to the weight ratio of 450:1350:225, prepares glue sand；Step 2, utilizes the glue sand preparation examination body that step 1 prepares, measures the first length of examination body, then boiled in 100 DEG C of water by examination body and boil 3～6 hours, then steam 3～6 hours 216 DEG C of temperatures after the described examination body demoulding；Step 3, measures examination body length after step 2 presses steaming to process, and the length after steaming according to pressure calculates tensile strain rate with just long, characterizes the volume stability after high MgO hardening of cement with the tensile strain rate calculating gained.Evaluation methodology method of the present invention is simple to operate, and course of reaction is steady, it is not necessary to complicated consersion unit, it is adaptable to the cement stability evaluation that cooling is shunk resisted by mass concrete.
Description
Technical field
The present invention relates to cement performance detection technique field, particularly relate to a kind of method evaluating high MgO cement stability.
Background technology
After cement and water mixing, in hardening process, owing to carbonization, chemical reaction and variations in temperature can cause volume contraction.In concrete for hydraulic structure hardening process, temperature shrinkage impact is bigger.Control the MgO(periclase in cement to a certain extent), CaO or sulfate, it is possible to improve the volumetric expansion of cement in concrete for hydraulic structure.The method is to offset owing to temperature reduces one of important channel causing water conservancy project dam concrete to shrink.If the hydration process of expansion sources controls well, it is possible to mate with the contraction phase of cement minerals hydration process, concrete for hydraulic structure volume stability will be produced positive effect.In CaO, MgO and sulfate expansion sources, owing to MgO expands stable, not easily relaxing obtains extensive concern.If but the MgO(periclase in cement), CaO or sulfate surplus more, cement matrix harden after also may proceed to produce expand, therefore concrete for hydraulic structure it is possible to can be destroyed.The time occurred due to this destruction is longer, the aquation unpredictable this destruction probability in a short time under normal condition, is typically based on short time acceleration of hydration, and test examination body change in volume result is predicted.Existing GB/T750 " Autoclave method for soundness of portland cement " dominant response is the expansion status of MgO in cement, and GB/T1346 " cement normal consistency water consumption, setting time, the stability method of inspection " dominant response is the expansion status of CaO in cement.It should be noted that GB/T750 and GB/T1346 is both for the volume method of testing that general concrete cement is formulated.Owing to not having the detection method of the suitable prediction cement and expanded rate of high MgO, in clinker, concrete compensation is utilized and fails to be utilized effectively always by periclase delayed expansion.
Concrete for hydraulic structure is different from general concrete, and one is that the cement amount needed in unit concrete is less, and two is that hydrated cementitious lies substantially in adiabatci condition, and internal temperature even can reach 60 DEG C, and after dam temperature slowly declines, temperature shrinkage is bigger.At present, mostly adopting and bury cooling water pipe underground, the mode carrying out concrete-agitating even with frozen water reduces concrete temperature, to reduce temperature shrinkage.Some engineerings also attempt adopting the outer mode mixing extender, reduce concrete temperature and shrink.And in mix MgO, namely improving content of MgO in clinker is very important approach.But owing to GB/T750 is the cement stability method of inspection worked out for general concrete, cause the cement qualified according to this standard test, do not reach the requirement of concrete for hydraulic structure temperature-compensating, and the cement of concrete for hydraulic structure requirement can be reached, the cement of requirement is disclosure satisfy that by GB/T750, do not reach the effect of concrete for hydraulic structure temperature-compensating, it is necessary to find the cement stability detection method mated with concrete for hydraulic structure.
Existing GB/T750 " Autoclave method for soundness of portland cement " standard adopt press-steamed method measure the stability of high MgO (periclase) clinker.Normal consistency is utilized only to starch two examination bodies of molding 25*25*285, first boil in 100 DEG C of water and boil three hours, again at 216 DEG C, steaming three hours is pressed under 2.0Mpa, test examination body pressure steam after with the change than length of the first appearance, characterize the volume stability after the hardening of high MgO (periclase) clinker with this tensile strain rate.
The delayed expansion that periclase produces can resist mass concrete cooling contraction distortion, and in expansion sources, only the expansion of MgO is not easy to be relaxed.And undertaken testing after mass concrete prepared by the cement meeting requirements hardens by GB/T750, microdilatancy can only be produced, even shrink, it is impossible to meet the requirement of mass concrete microdilatancy.Actually concrete is the mixed hardening body of cement, water, aggregate, and interstitial hole is more entirely different with cement paste situation, is more suitable for cement mortar as object of study.
What GB/T750 described is the expansion status trying body under naturalness, it is impossible to characterize the stress situation that expansion sources produces.Confined expansion method is combined by this method with pressure steaming method, accelerates cement minerals aquation by pressing to steam, and characterizes cement volume stability with glue sand free swelling rate and self-stress value.
Summary of the invention
The purpose of the present invention is to propose to a kind of method evaluating high MgO cement stability, to solve the problem that high MgO cement stability cannot be waken up with a start accurate evaluation by existing clean slurry stability detection method.
In order to solve above-mentioned technical problem, present invention employs following technical scheme: a kind of method evaluating high MgO cement stability, comprise the following steps:
Step 1, mixes high MgO cement to be measured, iso standard sand, water according to the weight ratio of 450:1350:225, prepares glue sand；
Step 2, utilizes the glue sand preparation examination body that step 1 prepares, measures the first length of examination body, then boiled in 100 DEG C of water by examination body and boil 3～6 hours, then steam 3～6 hours 216 DEG C of temperatures after the described examination body demoulding；Preferably, pressure is steamed and is carried out under 1.5～2.2Mpa pressure.
Step 3, measures examination body length after step 2 presses steaming to process, and the length after steaming according to pressure calculates tensile strain rate with just long, characterizes the volume stability after high MgO hardening of cement with the tensile strain rate calculating gained.
Compared with prior art, the beneficial effects of the present invention is:
Try body formed after it is boiled boil, press steaming, the mode of this acceleration of hydration can accelerate the aquation of cement and MgO simultaneously.Occurring the MgO in the cement mortar plastic stage to expand harmless, only after Behavior of Hardened Cement Paste hardens, MgO continues expansion and will result in hardenite stress raisers, damages；Above-mentioned process can accelerate cement simultaneously and MgO expands, and expands, for prediction MgO, the risk being likely to result in significant.
Additionally, evaluation methodology of the present invention can characterize cement volume stability in mass concrete.Test method is simple to operate, and course of reaction is steady, it is not necessary to complicated consersion unit, it is adaptable to the cement stability evaluation that cooling is shunk resisted by mass concrete.
Detailed description of the invention
Below in conjunction with specific embodiment, the present invention is described in further detail, but not as a limitation of the invention.
At the low-heat portland cement (KH=0.86+0.02, n=0.80+0.02, p=0.80+0.02) that Sichuan Jia Hua Cement Co., Ltd produces, adjust raw-meal ingredient, make MgO=4.95% in grog, 5.99%, 7.03%, 7.43%, 8.06%, 8.16%.Traditionally the method for testing of GB/T750, evaluation of the present invention are tested respectively for the method for high MgO cement stability of concrete for hydraulic structure, concrete autogenous volumetric deformation test, and result data is in Table 1.
Evaluation of the present invention, for the method for the high MgO cement stability of concrete for hydraulic structure, comprises the following steps:
Step 1, mixes high MgO cement to be measured, iso standard sand, water according to the weight ratio of 450:1350:225, prepares glue sand；
Step 2, utilizes glue sand preparation examination body (25mm*25mm*285mm) that step 1 prepares.Measure the first length of examination body after the demoulding, then examination body is boiled in 100 DEG C of water and boil 3～6 hours, then at 216 DEG C of temperature, under 2.0Mpa pressure, carry out pressure steaming 3～6 hours；
Step 3, measures examination body length after step 3 presses steaming to process, and the length after steaming according to pressure calculates tensile strain rate with just long, characterizes the volume stability after high MgO hardening of cement with the tensile strain rate calculating gained.Tensile strain rate according toCalculate, wherein LxExamination body length, L after steaming for pressure0For long at the beginning of examination body.
Table 1
Adopting the inventive method, it is qualified that expansion rate ranges for 0.05%～0.10%.Research also finds at MgO > after 8.0%, between the difference examination body of a sample, expansion rate is jumped difference and is strengthened, it was shown that after MgO > 8.0%, in hardenite, MgO expands uneven trend.
As can be seen from the above table, the test data that the present invention obtains is consistent with concrete autogenous volumetric deformation conclusion, has good dependency.And GB/T750 method is all undesirable with the dependency of the dependency of MgO and concrete autogenous volumetric deformation.When MgO is increased to 7.43% from 5.99%, the expansion rate of GB/T750 method declines on the contrary.
Above example is only the exemplary embodiment of the present invention, is not used in the restriction present invention, and protection scope of the present invention is defined by the claims.The present invention in the essence of the present invention and protection domain, can be made various amendment or equivalent replacement by those skilled in the art, and this amendment or equivalent replacement also should be regarded as being within the scope of the present invention.
Claims (2)
1. the method evaluating high MgO cement stability, it is characterised in that said method comprising the steps of:
Step 1, mixes high MgO cement to be measured, iso standard sand, water according to the weight ratio of 450:1350:225, prepares glue sand, and in described high MgO cement, MgO mass fraction is 7.43%, 8.06%, 8.16% or 8.56%；
Step 2, utilizes the glue sand preparation examination body that step 1 prepares, measures the first length of examination body, then boiled in 100 DEG C of water by examination body and boil 3～6 hours, then steam 3～6 hours 216 DEG C of temperatures after the described examination body demoulding；
Step 3, measures examination body length after step 2 presses steaming to process, and the length after steaming according to pressure calculates tensile strain rate with just long, characterizes the volume stability after high MgO hardening of cement with the tensile strain rate calculating gained.
2. the method for the high MgO cement stability of evaluation according to claim 1, it is characterised in that the pressure in step 2 is steamed and carried out under 2.0～3.0Mpa pressure.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310718641.6A CN103713116B (en) | 2013-12-24 | 2013-12-24 | A kind of method evaluating high MgO cement stability |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201310718641.6A CN103713116B (en) | 2013-12-24 | 2013-12-24 | A kind of method evaluating high MgO cement stability |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN103713116A CN103713116A (en) | 2014-04-09 |
| CN103713116B true CN103713116B (en) | 2016-07-27 |
Family
ID=50406257
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201310718641.6A Active CN103713116B (en) | 2013-12-24 | 2013-12-24 | A kind of method evaluating high MgO cement stability |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN103713116B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN106908343B (en) * | 2017-03-24 | 2019-04-02 | 中国建筑材料科学研究总院 | The measuring method of periclase degree of hydration in cement |
| CN106969996B (en) * | 2017-03-24 | 2019-04-02 | 中国建筑材料科学研究总院 | The method that minusing quantitative determines periclase mass percentage in cement |
| CN106885752B (en) * | 2017-03-24 | 2019-04-02 | 中国建筑材料科学研究总院 | The measuring method of periclase mass percentage in cement |
| CN106885753B (en) * | 2017-03-24 | 2019-04-02 | 中国建筑材料科学研究总院 | The method that minusing measures periclase degree of hydration in cement |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1763525A (en) * | 2005-10-12 | 2006-04-26 | 中国建筑材料科学研究院 | Method and apparatus for measuring rapid drying shrinkage of cement-based material |
| CN101082619A (en) * | 2006-05-31 | 2007-12-05 | 上海宝钢综合开发公司 | Method for detecting stabilizing ability of steel slag sand for replacing sand |
| CN102825663A (en) * | 2012-09-07 | 2012-12-19 | 贵州师范大学 | Method for determining MgO soundness mixing amount in hydraulic concrete |
-
2013
- 2013-12-24 CN CN201310718641.6A patent/CN103713116B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1763525A (en) * | 2005-10-12 | 2006-04-26 | 中国建筑材料科学研究院 | Method and apparatus for measuring rapid drying shrinkage of cement-based material |
| CN101082619A (en) * | 2006-05-31 | 2007-12-05 | 上海宝钢综合开发公司 | Method for detecting stabilizing ability of steel slag sand for replacing sand |
| CN102825663A (en) * | 2012-09-07 | 2012-12-19 | 贵州师范大学 | Method for determining MgO soundness mixing amount in hydraulic concrete |
Non-Patent Citations (2)
| Title |
|---|
| 水泥标准稠度用水量、凝结时间、安定性检验方法;颜碧蓝 等;《中国人民共和国国家标准 GB/T1346-2001》;20011001;第1-8页 * |
| 水泥蒸压安定性试验方法;张大同 等;《中华人民共国家标准GB/T750-92》;19930601;第1页：1 主题内容与适用范围、4 术语；第2-3页：9 试件的煮沸、10 试件的压蒸以及11结果的计算与评定 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN103713116A (en) | 2014-04-09 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| Galobardes et al. | Estimation of the modulus of elasticity for sprayed concrete | |
| CN103713116B (en) | A kind of method evaluating high MgO cement stability | |
| Galobardes et al. | Maturity method to predict the evolution of the properties of sprayed concrete | |
| Shen et al. | Relationship between tensile Young’s modulus and strength of fly ash high strength concrete at early age | |
| Kwan et al. | Adding limestone fines as cement paste replacement to reduce shrinkage of concrete | |
| CN104291757B (en) | A kind of non-evaporating pressure PHC pile tube being applicable under corrosive environment | |
| CN104496387A (en) | Similar material based on softening characteristics of soft rocks after encountering water and preparation method for similar material | |
| CN106517969B (en) | Rapid-hardening water does not leak and preparation method thereof | |
| Meng et al. | A strength-based mix design method for recycled aggregate concrete and consequent durability performance | |
| Su et al. | The influence of salt-frost cycles on the bond behavior distribution between rebar and recycled coarse aggregate concrete | |
| CN106587683A (en) | Method for improving water resistance of magnesium phosphate cement base | |
| Zhang et al. | An experimental study on the lateral pressure of fresh concrete in formwork | |
| CN104591660B (en) | Modified inorganic waterproof plugging material | |
| Pinto et al. | Unified modeling of setting and strength development | |
| CN101786819A (en) | Compound expanding agent and application thereof in blocking concrete for diversion tunnel | |
| CN105806737B (en) | The assay method of building mortar polypropylene fibre content | |
| CN110981392A (en) | Self-leveling thermal insulation mortar and preparation method thereof | |
| CN110372320A (en) | A kind of phosphate cement cement mortar ratio method | |
| CN105967567A (en) | High-polymer quick structure repairing material special for bridge expansion joint and preparation method thereof | |
| CN105315977A (en) | Oil well cement retarder and preparation method therefor | |
| Cui et al. | Early solidification process of the slurry with quicklime for fissure restoration of earthen sites | |
| CN104250076A (en) | Emergency first-aid repair special cement for construction engineering | |
| Galobardes et al. | Wet mix sprayed concrete set accelerating admixtures: Comparison between traditional aluminate based accelerators and new formulations of alkali free accelerators | |
| CN109942234A (en) | A kind of foam concrete preparation method adding aqueous epoxy resins and curing agent | |
| Sun et al. | Experimental study on the impact of admixture for concrete heat of hydration and early-age contractile properties |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C06 | Publication | ||
| PB01 | Publication | ||
| C10 | Entry into substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant |