JPH03170354A - Ultrahigh early strength cement composition - Google Patents

Abstract

PURPOSE:To obtain an ultrahigh early strength cement composition, capable of developing a high strength at a material age of one day by containing a specific amount of gypsum in a binder of a specified composition composed of ultrafine blast furnace slag powder having a specific particle size distribution and portland cement. CONSTITUTION:An ultrahigh early strength cement composition, containing 5-20 pts.wt. gypsum in 100 pts.wt. binder composed of 30-70 pts.wt. ultrafine blast furnace slag powder (with >=13000cm<2>/g Blaine specific surface area), having <=6mum maximum particle diameter and containing >=50 pts.wt. particles having <=2mum particle diameter and 70-30 pts.wt. portland cement, capable of developing a high strength at a material age of one day and utilizable for cast-in-place concrete, etc. Quick hardening properties can be also provided thereto by blending 0.5-2.5 pts.wt. aluminum sulfate with 100 pts.wt. aforementioned cement composition. The above-mentioned composition is capable of developing practical strength of mortar concrete for several hr even in steam curing at relatively low temperatures.

Description

[Detailed Description of the Invention] <Industry> Second Field of Application The cement composition according to the present invention is an ultra-early strength cement composition that can exhibit high strength in one day and has quick hardening properties. Concerning cast-in-place concrete,
Can be used for repair work such as prestressed concrete, emergency construction, and overlay of paving concrete. By using this cement composition in mortar and concrete, it is possible to quickly remove the formwork, improve the curing method, and shorten the curing period. In addition, the strength development effect of steam curing is remarkable, and practical strength can be achieved in a few hours, increasing the turnover rate of product formwork and improving productivity.
We believe that it can be used in a wide range of fields, including economic effects, such as the following.

<Conventional technology> Ultra-early-strength cement is standardized in JISR5201 as ultra-early-strength Portland cement, and the compressive strength of mortar according to JIS for commercially available and proven wood cement is ■
200~2301f/cA in 1 day, 35'OK in 3 days
It is about 9 f /cJ. The main technology was to increase the amount of alisotho (3CaOSI02), which is the main mineral of Portland cement clinker minerals, and to increase the fineness of the cement to about 6,000 aM/9 at the Blaine specific surface (( be.

However, since wood cement has a high powder content, when it is applied to concrete, it suffers from rapid initial hydration, resulting in poor workability and latheability. As a result, it loses its solid superiority in strength over early-strength Bol 1 land cement, and its use is limited to special cases.

Cement that determines quick hardening properties include dienoto cement, cement made by mixing Auin clinker with Bol 1 and Ranodocemen 1, and cement mixed with alumina cement or general-purpose cement. It is called one hour cement as opposed to one hour cement, and is mainly used for emergency construction, repair buttons, and spraying.

Cement using dienodic cement and Auin-based clinker utilizes the early formation of phosphorus phosphorus from calcium aluminate hydrate due to the presence of alkali and gypsum, and these cements have a unique property of continuous hardening. Although it is made of cement, it is essential to use a retardant to secure the space between the ships.

Alumina cement utilizes the hydration of a large amount of carunium aluminate, and has the problem of hydrate transfer, making it difficult to use as a permanent concrete.

There are many additives that can be added to cement to give it quick hardening properties, but they are generally difficult to control within a usable range and have poor reproducibility. Also, although it has continuous hardness, its strength is low and its strength development is poor, so it cannot be used for practical concrete. ! }Na〈Special use
It is only used in part of Grau 1).

In terms of conventional technology, there has been no development example of ultra-early strength cement that uses blast furnace slag as its main advantage, or that has added rapid hardening properties.

<Problems to be solved by the invention> Ultra-early and strong Pol 1 land cement and quick-hardening cement were developed focusing on Portland cement clinker minerals, and their fineness is 5,000 in Blaine specific surface area.
~6.000 cd/9, which is high. Ultra-early-strengthening Portland cement has difficulty in workability, and the concrete strength level in one day is superior to 1 (poor, and the increase in strength after the initial rate is also small. With rapid-hardening cement 1-, it is difficult to control the work time) , high water utilization, low strength increase,
It has drawbacks such as high cost, and also cannot be mixed with general-purpose cement, making it difficult to manufacture at a ready-mixed concrete factory and requiring special concrete manufacturing equipment.

The present invention does not focus on Portland cement clinker, but rather on the hydration characteristics of fine powder of blast furnace slag sieve, and the technical idea is completely different. Developing a cement composition that uses blast furnace slag as the main material and can impart ultra-early strength and quick-hardening properties will improve the workability of concrete, increase strength after the initial stage, and improve durability. is considered to be of high value.

The name of the invention is that one bite has a strong odor.
It surpasses the strength of strong Portland cement, and its rapid hardening properties (l hardness) make it possible to obtain the required hardening properties in a few hours, and by steam curing, practical strength concrete can be produced within a few hours. We have discovered a blast furnace slag-based ultra-early strength cement that is highly functional.

Means for Solving the Problems> There are various mechanisms for using cement and additives to obtain rapid hardening, but the production of ettringite is effective and the strength development is stable. In addition to ettringite, calcium silicate aquariums (C-3-
1-1) It is necessary to start eating early and increase the amount produced.

The main focus of the present invention is ettringite and C-S-I-
This study focused on the water utilization characteristics of Portland cement depending on the particle size and blending amount of pulverized blast furnace slag powder, which affects the hydration requirement of 1. When blast furnace slag particles come into contact with water, the surface hydration of the particles quickly evaporates, resulting in extremely ``C monopoly,'' but with Bonoretland cement crimp J particles, and subsequent water utilization is slow. The blast furnace slag powder used in 1゜5 i-+ cement has a maximum particle size of 48 μm, an average particle size of 9/'m, and a Blaine specific surface area of 4.000 cA.
The initial strength of blast furnace cement is generally said to be low because powder dust of this fld degree has poor initial strength development. By reducing the blast furnace slag particle size, the elution amount of each ion in the alkaline solution increases quadratically.
02) Activate initial water usage unprofitably.

By using the 1b furnace slag highly fine powder of the present invention,
In the presence of gypsum, the water utilization of the slag itself and of the alitte proceeds rapidly, and ettringite from calcium aluminate ethrinate {C enables the early growth of C-S-H, resulting in ultra-early strength. It was found that a stable hydrate form can be produced even in long-term cultivation by adding it to Shiraki. Fast hardening II
The presence of a relatively large amount of so4' in the A-phase in the alkaline liquid phase is necessary for the production of Ettringai 1, which causes IJ. It has also been found that aluminum sulfate is suitable for the process and has the effect of increasing the initial strength.It is well known that the hydration of blast furnace slag particles is highly temperature dependent;
Mortar concrete using the ultra-early-strengthening cement composition of the Wood invention significantly promotes water utilization under temperature conditions due to steam curing, and can develop high strength in a short period of time.

The material structure of the present invention will be explained below.

The smaller the particle size of blast furnace slag is, the better for determining ultra-early strength, but if the maximum particle size is 6 μIn or more (Blaine specific surface 12,000 cJ/'Y or less), JI8
It is not possible to obtain a mortar compressive strength of 220K9f/cJ or more in one day.Also, it is poor in quick hardening due to aluminum sulfate.

In the case of high-fine blast furnace slag powder containing 50 parts by weight or more of particles with a maximum particle size of 6 μn1 or less and 2 μm or less, by blending 30 to 70 parts by weight with Portland cement, compaction strength can be reduced by the 1-day regulation. 0 K9f/al 2 was obtained, and the formulation 1c J: t'C I. t 2 5 0
K9 f/cJ or more, 400K9 (/ty) with 3-day interest rate
A grade of A or higher is easily obtained.

In addition to the cement specified by JISR 5201K, white Portland cement can be used as the Portland cement. From the purpose of the present invention, it is preferable to use strong Boltland cement 1-, which has a large number of ants.

Gypsum is an important component in the cement composition of the present invention,
The form of the gypsum does not matter, but the powder level is 7g at the Blaine surface ratio.
44,000 cA/9 or more is preferable. The amount of plaster is bond +4. u2+: Furnace slag fine powder + Bortland cement 1-) It is preferable to use 5 to 20 parts by weight of C5 to 20 parts by weight, and the optimum amount of gypsum changes depending on the blending amount of ll'Jl furnace slag fine powder. However, as the blending amount increases, the optimal amount of gypsum increases.

{jl[Aluminum has a function as a quick-hardening material for Portland cement, but when the high-fine blast furnace slag powder of the present invention is used, the continuous hardening property is not impaired. 250Kp in daily strength
f/cJ or more can be 1 (}.The amount of aluminum sulfate added to 100 parts by weight of the cement composition is 05
A range of ~25 parts by weight is preferable; if it is less than 25 parts by weight, the quick hardening effect will be poor; if it exceeds 25 parts by weight, the quick hardening property will be reduced, but the amount of water per unit to obtain work will also increase, and the 1-day strength will also decrease. It is used as an ultra-early and strong cement. }
I can't do it. Aluminum sulfate can be handled as a powder or as a solution, and must be treated with mortar before turning. There is an advantage of being able to choose the waiting period for adding Hakusan to concrete.

It is common for the physicochemical activity of cement-based shrines to increase by increasing the temperature, but in the case of the Song dynasty, where high carbon slag fine powder was used, the initial water use activity due to temperature differences was greatly affected by the particle size. . The cement composition according to the present invention also has a steam curing odor at a relatively low temperature, which increases the initial water availability of Portland cement powder and blast furnace slag (1)'G fine powder.
It is possible to obtain the practical strength of mortar concrete in a few hours.

Examples will be given and explained below.

Example 1 A cement composition consisting of the second barley composition was trial-produced using two types of fine slag powder with different particle sizes (based on laser beam diffraction method) and different Blaine specific surfaces as shown in Table 1.
01, mold the mortar,
Compressive strength was measured after 7 days.

This example also shows that the particle size of fine slag powder has a remarkable effect on the ultra-early strength of cement composites, with a maximum particle diameter of 1
For slag fine wood of 21' m or more, Ll strength is 200K.
9f/c+fl or more F, but the maximum particle size of the present invention is 6 μm
When using the following fine slag powder (USP), conventional N
A value exceeding the strength of 17'-strong Voltland Cement 1~ was obtained, and 250~300 Kyf/cA in one day,
It was discovered that more than 400 K9f/ca could be secured in 3 days.

The ability to obtain ultra-early strength cement composites using blast furnace slag is considered to be of great significance as it also contributes to improving the durability of concrete.

Table 1 Table 2 Table 1-I P C: Early-strength Portland cement Example 2 Using the three types of fine slag powder shown in Table 1, a cement composition having the composition shown in Table 3 was prepared as a sample, and JIS R
5201) Shape C mortar according to C, 6 hours, ■
The compressive strength was measured on days 1 and 3. The results are shown in Table 3.

This example also shows that the particle size of the fine slag powder has a remarkable effect on the quick hardening and ultra-early strength of the cement composition, and the fine slag powder (S S P) with a maximum particle size of 12 μm or less has a small amount. By doing more, your daily strength will increase.

When using the fine slag powder (USP) of the wood invention example, 6
N interval TeI O-1 5 K9 (/oR, 1 day f
Over 250K9f/cJ, 400K9r/ty in 3 days!
It was confirmed that high strength of + or higher can be easily achieved.

Table 3 Example 3 In order to confirm the strength effect of steam curing of mortar using the cement composition of the present invention, based on the formulation shown in Table 4, mortar C was molded based on JIsR52o1.

In formulations with a low water ratio of W/C 4 5%, water reducing agent Mighty I50 (manufactured by Kao) was added to the cement composition (TO.7
5 parts by weight was used. The conditions for steam curing are after mortar molding t)
The compressive strength was determined for 15 seconds, a gastric temperature rate of 15°C/h, and a maximum temperature of 50°C for 1 hour for 6 hours. The strength results are shown in Table 4.

In this example as well, the effect of steam curing of the cement composition using fine slag powder (USP), which is the main elemental phase of the present invention, is remarkable regardless of Wκ, and
The daily compressive strength is 150 with W/C 65% JIS mortar.
, 330K? f/cJ, and high intensities of 250 and 450κqr/rU were obtained by 1'J at W/C45%, respectively.

Table 4

Claims (3)

[Claims] (1) 30 to 70 parts by weight of highly fine blast furnace slag powder (plain specific surface area 13,000 cm^2/g or more) containing 50 parts by weight or more of particles with a maximum particle size of 6 μm or less and 2 μm or less,
An ultra-early strength cement composition characterized by high strength development in one day of age, containing 5 to 20 parts by weight of gypsum to 100 parts by weight of a binder consisting of 70 to 30 parts by weight of Portland cement. (2) The ultra-early-strengthening cement composition according to claim 1, which has rapid hardening properties and contains 0.5 to 2.5 parts by weight of aluminum sulfate per 100 parts by weight of the cement composition. (3) The ultra-early strength cement composition according to claims 1 and 2, which develops the practical strength of mortar concrete in several hours by steam curing.