JPS6140902A - Hydraulic composition for road - 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 hydraulic composition for roadbeds.

[Conventional technology]

Grain-adjusted crushed stone is known as a material for the upper road base course, and as a road base construction method, a bituminous stabilization method, a stabilization method using cement or lime, etc. are known.

These roadbed materials and roadbed construction methods are valued using equivalent conversion coefficients (Japan Road Association [Material constants specified in the Asphalt Paving Guidelines, conversion coefficients with road surface asphalt as 1]) which are design constants. It is customary to evaluate 0.35 for particle-sized crushed stone, 0680 for bitumen stabilization method, 0.55 for cement stabilization method, and 0.45 for lime stabilization method. Each is given as a standard value. When selecting such roadbed materials and construction methods, it is important to: ■ have a large equivalent conversion coefficient, ■ have excellent durability, and ■ do not cause shrinkage cracks during hardening, and will not cause uneven settlement of the embankment or subgrade. It is desired that the material be able to follow the deformation of the material and not cause cracks, that it be easily available and not limited to the area around the manufacturing site, and that it be inexpensive.

[Problem that the invention seeks to solve]

Regarding the above request items ■ to ■, the particle size-adjusted crushed stone mentioned above has problems in points ■ and ■, the bitumen stabilization method has problems in points ■, and the cement stabilization method has problems in points ■ and ■. In addition, the lime stabilization treatment method has problems in (1) and (2). In addition, the amount of traffic has increased significantly in recent years, leading to frequent problems with ruts.While improvements and developments in asphalt compositions are progressing, roadbed materials are required to have an increasingly high level of durability. It is starting to look like this.

On the other hand, it is known that granulated blast furnace slag, which is produced in large quantities as a by-product in the steel industry, has latent hydraulic properties, and some of it is also used as blast furnace cement, but compared to Portland cement, etc. The hardness activity is low and the compressive strength of the cured product is not sufficient.

Under these circumstances, the present invention aims to provide a hydraulic composition for roadbeds that uses granulated blast furnace slag as a main raw material and can satisfy the above requirements (1) to (3).

[Means for solving problems]

The present invention is characterized in that an appropriate amount of an alkaline stimulant is blended into granulated blast furnace slag that has been crushed and adjusted to have a fineness index (F value) of 80 to 200 as determined by the following formula. This is a hydraulic composition for roadbeds having the following features.

F value=P-10P5o+P.

(However, Plg) s PsO%Pso is the weight percentage passing through ASTM standard sieves No. 100, No. 50, and No. 30) [Operation] The well-known granulated blast furnace slag is made by quenching blast furnace slag with water and crushing it. It has latent hydraulic properties. However, normal granulated blast furnace slag has relatively coarse grains, with a small amount of fine grains of about 0.4 mmφ or less, and the fineness index (F value: same as before) is about 2.
It is as small as 0-50. Moreover, since a calcium carbonate film is formed on the particle surface due to contact with water or air during production, the hydraulic activity is low. However, when this granulated blast furnace slag is pulverized with a crusher such as a rod mill or a cone crusher until the F value reaches 80 or more, the surface area increases due to the finer particles and the surface coating layer described above is It was confirmed that the hydraulic activity was further increased, and the compressive strength of the cured product was also significantly improved. Figure 1 shows the relationship between the F value of crushed blast furnace slag and the unconfined compressive strength of the hardened product [However, 10% by weight of cement was added as an alkaline stimulant: Value after 14 days of age, a
W is a graph showing the amount (% by weight) of the blend relative to the fine aggregate.y1 As the F value of the granulated blast furnace slag increases, the compressive strength increases proportionally. And JIS
HMS, which is road slag specified in A 5015
It can be seen that in order to ensure the same uniaxial compressive strength as -25, it is sufficient to finely grind until the F value becomes 80 or more.

From the perspective of compressive strength, there is no upper limit for the F value, but pulverization until the F value exceeds 200 requires extremely high-performance crushing equipment and requires a large amount of time and energy to crush. Therefore, considering practicality based on economic efficiency, the upper limit of the F value is about 200.

However, for crushed blast furnace slag, even if the F value is 8-θ~
Even when it is within the range of 200, it is not possible to obtain practical hydraulic properties and cured product strength when used alone. However, when an appropriate amount of an alkaline stimulant is added to this, it is possible to obtain a cured product that exhibits hydraulic properties comparable to conventional hydraulic compositions containing cement or lime as the main components, and also exhibits excellent compressive strength. can.

As the alkaline stimulant, various alkaline substances which themselves have hydraulic properties can be used, but in consideration of economy and performance, Portland cement and lime are considered to be most suitable. We also investigated the suitable blending ratio of these stimulants, and found that if they were blended in an amount of 10% by weight or more to the crushed granulated blast furnace slag, as shown in Figure 2, the stimulant would have a uniaxial compressive strength comparable to that of HMS-25. It was confirmed that it is possible to ensure the If ordinary Portland cement is selected as the stimulant, the unconfined compressive strength of the cured product will increase as the amount of cement increases;
If it exceeds 50% by weight, the relative amount of granulated blast furnace slag used will be small and the original purpose of ``effective use of granulated blast furnace slag'' cannot be effectively utilized, so the blending amount of cement #'i50% by weight Hereinafter, it is desirable to suppress the content to 30% by weight or less. However, depending on the degree of compressive strength required, it is of course possible to mix more than the specified amount of cement. On the other hand, when using lime as an alkaline stimulant, the maximum uniaxial compressive strength is shown when <10 to 40% by weight (preferably 25 to 35% by weight) of lime is blended, as shown in Figure 3. , even less than 10% by weight or 40% by weight
It is not possible to obtain a satisfactory unconfined compressive strength even if the

As described above, the present invention uses inexpensive granulated blast furnace slag as the main raw material, finely pulverizes it, adjusts the fineness index to within a specific range, and then mixes it with an appropriate amount of an alkaline stimulant. It has now become possible to obtain a hydraulic composition that is completely comparable to conventional hydraulic materials for roadbeds. In putting the hydraulic composition of the present invention into practical use, it may be used by mixing it with aggregate such as particle size-adjusted crushed stone on the road, or it may be used as it is in the form of mortar without adding aggregate. Example] 80 parts by weight of granulated blast furnace slag was finely pulverized to give an F value of 112, and ordinary Portland cement was mixed with water and hardened to investigate its performance as a roadbed material. Material property values were obtained.

When the cured product was examined for changes in -axial compressive strength over time, the results shown in FIG. 4 were obtained.

In addition, Fig. 4 also shows the changes over time of the cement stabilization treated material and JIS A 5015 standard HMS-25 as comparative data.

Table 1 In Table 1, “Modified CBRJ has the following meaning,
The standard value for roadbed material is R811 or higher.

- The standard value of axial compressive strength is “i 2 kgf/CII
+2 or more.”

(Modified CBR) CB R (California Bearing R)
atio) is an evaluation value of the material strength of roadbeds, roadbeds, etc. used for roads, and the test method is J r s A1
211-197Or Subgrade Soil Bearing Ratio (CBR) Test Method" and "Modified CBR Test Method for Subgrade Materials" specified in Asphalt Pavement Requirements #1 (Japan Road Association). Modified CBR
means the value obtained by the latter method.

It can also be seen from Table 1 and FIG. 4 that the cured product of the hydraulic composition according to the present invention has excellent effects as a roadbed material.

[Effects of the Invention] The present invention is configured as described above, but the key point is that granulated blast furnace slag is finely pulverized and adjusted so that the rope particle size index falls within a specific range, and a specific amount of an alkaline stimulant is By using it in combination with the present invention, it has become possible to provide a hydraulic composition for roadbeds at a low cost, which has excellent hydraulic activity and excellent compressive strength after curing.

[Brief explanation of drawings]

Figure 1 is a graph showing the relationship between the fineness index (F value) and -axial compressive strength of crushed granulated blast furnace slag, and Figures 2 and 3 are graphs showing the relationship between the amount of cement or lime added and uniaxial compressive strength. The graph shown in FIG. 4 is a graph showing the relationship between the age of the cured product and the unconfined compressive strength.

Claims (1)

[Claims] The fineness index (F value) determined by the following formula is 80 to 2.
1. A hydraulic composition for roadbeds, comprising 10 to 50% by weight of an alkali stimulant added to granulated blast furnace slag. F value = P_1_0_0 + P_5_0 + P_3_0 (However, P_1_0_0, P_5_0, P_3_0 are the weight percentages passing through ASTM standard sieves No. 100, No. 50, and No. 30)