JPS62123046A - Manufacture of hydraulic road bed material - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing a hydraulic roadbed material using steelmaking slag and granulated blast furnace slag as raw materials, and particularly relates to a method for producing a hydraulic roadbed material using steelmaking slag and granulated blast furnace slag as raw materials, and particularly for improving the physical properties (especially compressive strength) of the hardened material. The present invention relates to a method for producing a novel hydraulic roadbed material that has good properties and improved swelling and collapsing properties.

[Prior art] Steelmaking slag, which is produced in large quantities as a by-product during the steel production process, is extremely heavy because its main components are lime, silica, and iron oxide, and the mineral phase is composed of calcium silicate, bustite, calcium ferrite, titanate, etc. It is also a hard mineral. For this reason, various studies are being conducted to try to use it effectively as aggregate for roadbed materials, etc. However, this steelmaking slag contains a very large amount of lime, and has the defect that the lime absorbs moisture in the soil, expands, and collapses, making it unsuitable for use as a roadbed material that requires durability. lack Moreover, since the main component of steelmaking slag is lime and the main mineral is calcium silicate, there is a problem that even after treatments such as aging, the eluate remains highly alkaline with a pH of 10 to 12. It is only used as timber and temporary road material. Even under these circumstances, there are still technologies that have succeeded in effectively utilizing steelmaking slag as a roadbed material.
No. 55-44802, etc. have been proposed.

[Problems to be solved by the invention] However, in the above-mentioned Japanese Patent Publication No. 50-32927, steelmaking slag is used as so-called tararasharan for the lower roadbed, and high levels of compressive strength and durability are required. It cannot be used as an upper layer roadbed material, and on the other hand,
Although it is thought that the roadbed material No. 44802 can satisfy the required performance in terms of physical properties, it can only achieve its purpose by using a small amount of steelmaking slag in combination with a large amount of hydraulic blast furnace slag, and the steelmaking slag is consumed. There is a natural limit to the amount. Moreover, in this method, a large amount of hydraulic blast furnace slag, which has high commercial value as a cement raw material, etc., must be diverted to this field, so there is a problem that the supply amount of hydraulic blast furnace slag as a cement raw material, etc. is reduced.

Under the above-mentioned circumstances, the present invention aims to provide a method for manufacturing a roadbed material that effectively utilizes a large amount of steelmaking slag and has sufficient hydraulic hardness, physical properties, and durability for practical use as an upper roadbed material. That is.

[Means for Solving the Problems] The present invention combines steelmaking slag with a particle size of 30 mm or less and granulated blast furnace slag with a fineness index (F) of 50 to 110 expressed by the following formula as F '' P too + P so+ P 3G (However, 2100, P 50+ P50+P30 is A37M
Weight percentage passing through standard sieves No. 100, No. 50, and No. 30) The gist is that the ingredients are blended so as to satisfy the following formula.

(400-3,6F)≦10' (G/S)50≦S
≦80 However, G: Blending ratio of granulated blast furnace slag (% by weight) S: Blending ratio of steelmaking slag (%).

[Function] As mentioned above, the mineral phase of the steelmaking slag used in the present invention is a hard and heavy mineral mainly composed of calcium silicate, bustite, etc., but in order to ensure its suitability as a roadbed material, It must be crushed to a particle size of 30 mm or less.

On the other hand, granulated blast furnace slag, which is used in combination with steelmaking slag, is obtained by rapidly cooling blast furnace slag with high-pressure water, and as is well known, it has latent hydraulic properties, but its particle size distribution is within the range of coarse sand. (The fine grain size F of normal granulated blast furnace slag is 20 or more and less than 50). Therefore, if the granulated blast furnace slag is mixed with steelmaking slag as it is, the coarse particles will increase and the hardened product will Physical properties become poor. However, if granulated blast furnace slag is crushed and refined to a predetermined particle size composition and mixed with steelmaking slag, the voids caused by the lack of fine particles in the steelmaking slag will be filled with the fine particles of the granulated blast furnace slag, reducing the overall porosity. In addition to improving the strength of the hardened product, the surface area of the granulated blast furnace slag itself increases due to its finer grain size, which greatly improves its hydraulic properties.Furthermore, the reduction of pores within the particles improves the hardness of steelmaking slag. It was confirmed that the expansion and disintegration properties were also suppressed and the durability of the cured product could be significantly improved. In particular, granulated blast furnace slag originally has many air bubbles in its particles and is rich in ridge angles, and can be easily reduced to fine particles using a cone crusher. Glass material has a high level of hydraulic properties, so by blending it with steelmaking slag to act as a binder, a roadbed material with excellent hydraulic properties and strength of the cured product can be obtained. It has been confirmed that the effect of using granulated blast furnace slag in combination is closely related to its particle size composition and blending ratio with steelmaking slag. Incidentally, Figure 1 uses granulated blast furnace slag (before and after refining) with the particle size composition shown in Table 1, and calculates the mixing ratio (G/S) of the granulated slag/steelmaking slag. This figure shows the relationship between the uniaxial compressive strength of the cured product. However, the first
In the figure, the blending ratio of steelmaking slag is set to 60% (weight %: the same hereinafter), and the remaining component is blast furnace slowly cooled slag (a component with many fine particles and no expansion and collapse properties).

In addition, the sieve size of the A37M standard sieve No. 100, No. 50, and No. 30 is 0.15 mm, 0.3 m + n,
It is 0.6 mm.

As is clear from Figure 1, as the mixing ratio (G/S) of granulated blast furnace slag/steelmaking slag increases, the unconfined compressive strength of the hardened product tends to increase, and the grain size becomes finer. (those with a large F value) have a large effect of enhancing compressive strength. From these experimental values, we selected ``r12K, which is the unconfined compressive strength specified in the standard for conventional hydraulic slag hardened products.''
G/S value and fine grain size F required to obtain g-f/Cm2J
By extracting and arranging the value J of , the relationship shown in Figure 2 is obtained,
It turns out that the relationship expressed by equation [1] below holds true.

103 (G/S)≧(400-3,6F)... [
I] (The meanings of G, S, and F are as described above.) The effectiveness of [H can also be confirmed from the experimental data in Table 2 below, which was obtained by compounding to satisfy the relationship of this formula. .

Furthermore, as a result of examining the changes in unconfined compressive strength over time for each of the roadbed materials shown in Table 2 above, the compressive strength of all roadbed materials increased significantly over time, and at 180 days old, it reached 30 gf/c.
It was confirmed that the value was greater than m2.

In other words, if the blending ratio (G/S) of granulated blast furnace slag and steelmaking slag is adjusted to satisfy the relationship of Equation 11 above according to the fineness (F) of the granulated blast furnace slag used, -axial compressive strength It is possible to obtain a roadbed material that satisfies the standard value of thickness. However, as mentioned above, the purpose of the present invention is to use a large amount of steelmaking slag (50% by weight or more in terms of the composition ratio of the entire roadbed material), and the amount of granulated blast furnace slag that is mixed in such a large amount (the amount of granulated blast furnace slag mixed is naturally reversed) In order to ensure sufficient unconfined compressive strength due to the requirement that granulated blast furnace slag has a fineness of F of 50 or more (a fine grain that exhibits high hydraulic properties even in a small amount). must be used.

On the other hand, when granulated blast furnace slag is mixed with steelmaking slag, it has the effect of reducing the amount of expansion and fineness F. Relationship is third
As shown in the figure, the fine grain size F of granulated blast furnace slag is 11
If it exceeds 0, the effect of absorbing the amount of expansion on the steelmaking slag will be poor, making it impossible to satisfactorily suppress expansion and collapse of the hardened material. For these reasons, in the present invention, the fineness F of the granulated blast furnace slag is set in the range of 50 to 110.

Figure 4 is a graph showing the results of examining the unconfined compressive strength of the cured product when the G/S value and F value were variously changed (however, the amount of steelmaking slag was kept constant at 50% by weight). It can also be seen that a high level of single glaze compressive strength can be ensured by setting the F value in the range of 50 to 110.

Next, the blending amount of steelmaking slag is determined based on "effective utilization of steelmaking slag."
In order to meet the intended purpose, the lower limit was set at 50%,
The upper limit is preferably about 80% for the reasons shown below.

That is, as is clear from the formula I1, the F value is 50 to 11.
In the range of 0, there is a proportional relationship between the proportion S of steelmaking slag and the proportion G of granulated blast furnace slag, and as mentioned above, in a three-component system that includes air-cooled blast furnace slag as the third component, By reducing the amount of slowly cooled slag, the amount of steelmaking slag can be increased in proportion to the amount of granulated blast furnace slag. However, for hydraulic roadbed materials, in addition to the standards for physical properties shown in the margins of Table 2 above, there are also standards for particle size distribution, and as shown in Table 1, blast furnace water, which is classified as coarse sand and has a narrow particle size distribution, If too much crushed slag is added, the particle size distribution of the roadbed material will become uneven, leading to deviations from the specifications. Therefore, it is not possible to mix more than a certain amount of granulated blast furnace slag, and accordingly, the upper limit of the mixing ratio of steelmaking slag is also determined. If coarse-grained (F value is 50 or less) granulated blast furnace slag is used, the proportion of steelmaking slag should be approximately 70% or less even if the requirements of formula [I] above are specified. was confirmed. However, in the present invention, in which granulated blast furnace slag is used after being refined to an F value of 50 to 110, the blending ratio of granulated blast furnace slag to steelmaking slag can be reduced to 80%. Even when a steelmaking slag of 100% is mixed, it is possible to obtain a roadbed material that satisfies both the standards for physical properties and grain size composition. By the way, in Figure 5, the fine grain size is 50.
Roadbed material obtained by blending 17% of granulated blast furnace slag (F value = 44) with a fineness of less than 17% and 70% of steelmaking slag; The particle size distribution of the roadbed material obtained by blending 80% slag (the remaining components are blast furnace slowly cooled slag) was determined by JIS-A5Q15 (7
) This is shown in comparison with the range specified by HMS-25.

As is clear from this result, when using granulated blast furnace slag with a fine grain size of less than 50%, the upper limit for the content of steelmaking slag is considered to be 70% in terms of grain size composition; In the present invention, which uses the above-described granulated blast furnace slag, it is possible to obtain a roadbed material having a particle size structure that meets the standards even if the blending ratio of steelmaking slag is increased to about 80%. However, if the amount of steelmaking slag exceeds 80%, it becomes difficult to control the production process to ensure an appropriate particle size distribution, and it becomes impossible to suppress the expansion and disintegration of the hardened product to a low level. The slag content is the cured product -φ+hl)
As shown in the graph showing the relationship between E shrinkage strength (where the F value was kept constant at 80), the uniaxial compressive strength may deviate from the standard for hydraulic slag cured products depending on the G/S value. It comes out.

In the present invention, as long as the above-mentioned requirements are met, it is possible to use only two components, steelmaking slag and granulated blast furnace slag, as a roadbed material. It is best to mix an appropriate amount of air-cooled blast furnace slag to make a three-component roadbed material.

[Example] Using steelmaking slag, granulated blast furnace slag, and slow-cooled blast furnace slag with the component composition and particle size distribution shown in Table 3 below, these were mixed in the ratio shown in Table 4 to obtain the particle size shown in the table. The distribution and physical properties of the roadbed material were adjusted.

Using the three types of roadbed materials obtained, their performance as upper layer roadbed materials was investigated in the following manner. In other words, a road with a width of 10 m and a length of 5
After laying the lower base course material (balance) at three locations (total 150 m) over a length of 0 m, each of the above base base materials was laid as the upper base base material (15 cm thick), compacted, and asphalt mixture was further added to a thickness of 5 cm. The surface was paved with. Table 5 shows the physical properties of each layer.

When we investigated the condition of the roadbed one year after it was paved, we found that
There were no collapses, upheavals, depressions, or cracks in the road surface caused by the expansion of the upper roadbed material, and it was confirmed that the roadbed had excellent properties.

[Effects of the Invention] The present invention is constructed as described above, but the point is that by appropriately adjusting the blending ratio of granulated blast furnace slag and steelmaking slag according to the fineness of the granulated blast furnace slag, hydraulic properties, - A roadbed material with excellent axial compressive strength and durability can be manufactured, and a large amount of steelmaking slag can be effectively used as a raw material for the roadbed material within a range that satisfies the above requirements. Moreover, according to the present invention, the amount of granulated blast furnace slag, which has high added value as a cement raw material, can be significantly reduced, and the roadbed material can be provided at an extremely low cost.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between G/S value and unconfined compressive strength when various granulated blast furnace slags with different F values are used, and Figure 2 is a graph showing the relationship between unconfined compressive strength of 12 Kgf/C0.
A graph showing the relationship between the F value and the G/S value of granulated blast furnace slag to obtain a hardened product that is I2, FIG. 3 is a graph showing the relationship between the fineness F of granulated blast furnace slag and the expansion absorption rate, Figure 4 is a graph showing the influence of G/S value and F value on the single glaze compressive strength of the cured product. Figure 5 is the particle size distribution of the roadbed material specified in JIS and the particle size distribution of the roadbed material used in mounting. A graph showing,
FIG. 6 is a graph showing the relationship between the blending amount S of steelmaking slag and the unconfined compressive strength.

Claims (1)

[Claims] Steelmaking slag with a particle size of 30 mm or less and granulated blast furnace slag with a fineness index (F) of 50 to 110 expressed by the following formula are combined into F=P_1_0_0+P_5_0+P_3_0 (where P
_1_0_0, P_5_0, and P_3_0 are weight percentages passing through ASTM standard sieves No. 100, No. 50, and No. 30). (400-3.6F)≦10^3 (G/S)50≦S≦
80 However, G: Blending ratio of granulated blast furnace slag (% by weight) S: Blending ratio of steelmaking slag (%).