JP2007197239A - Mortar, hardened mortar product, and bridge - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide mortar which is lightweight and has good flowability, its hardened product, and a bridge using it. <P>SOLUTION: The mortar contains water of 350-400 kg, cement of 640-680 kg, and residual aggregate in its total volume of 1 m<SP>3</SP>. The aggregate consists of only lightweight fine aggregate substantially having a particle diameter of ≤1.2 mm and specific gravity of ≤1.3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a mortar, a cured product thereof, and a bridge using the mortar.

  Conventionally, as a method for reinforcing and repairing a structure, a method of filling a hollow steel member with concrete or mortar has been performed. The concrete and mortar used at that time must be (1) lightweight to suppress an increase in the weight of the structure, and (2) have good fluidity in order to satisfactorily fill. On the other hand, in structures such as bridges that are actually in service, (3) in order to perform construction in a short time and minimize social loss, it is necessary to have characteristics that it can be hardened quickly and obtain practical strength. It becomes.

  Patent Document 1 discloses a lightweight structure with a lightweight mortar comprising 15 to 25% by weight of a lightweight aggregate, 82 to 72% by weight of Portland cement, and 3 to 7% by weight of a hardening accelerator, and a small amount of a thickener and a setting modifier. It is disclosed that an object can be formed in a short time.

  Patent Document 2 discloses that 100 parts by weight of cement having a specific specific surface area, 10 to 40 parts by weight of fine particles having a specific specific surface area, 10 to 50 parts by weight of inorganic particles A having a specific specific surface area, and specific parts A hydraulic composition containing 5 to 35 parts by weight of inorganic particles B having a specific surface area, a water reducing agent, and water, wherein the total amount of the inorganic particles A and the inorganic particles B is 100 parts by weight of the cement. On the other hand, it is disclosed that a hydraulic composition of 15 to 55 parts by weight has excellent fluidity and excellent mechanical properties after curing.

JP-B-1-46478 Japanese Patent No. 3397775

However, when a conventional concrete or mortar is filled into a structure and the structure is reinforced and repaired, for example, the lightweight mortar disclosed in Patent Document 1 satisfies the above feature (1). The feature of 2) may not be satisfied, and the feature of (3) could not be expected.
On the other hand, for example, the hydraulic composition disclosed in Patent Document 2 is a so-called grout material, and satisfies the characteristics of the above (2) and (3), but has a specific gravity of about 2 or more. The feature of (1) could not be satisfied.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the mortar which is lightweight and good fluidity, its hardened | cured material, and a bridge using the same. Furthermore, an object of the present invention is to provide a mortar that can be quickly cured to obtain practical strength, a cured product thereof, and a bridge using the mortar, in addition to the above features.

In order to solve the above problems, the present invention employs the following means.
That is, the mortar of the present invention contains 350 kg or more and 400 kg or less of water, 640 kg or more and 680 kg or less of cement, and the remaining aggregate in a total volume of 1 m ³ , and the aggregate is substantially granulated. It consists only of a lightweight fine aggregate with a diameter of 1.2 mm or less and a specific gravity of 1.3 or less.
Increasing the water improves the flowability of the mortar, but tends to cause separation of water and solids (breathing). Moreover, when water is decreased, the fluidity of the mortar is deteriorated. Therefore, the blending amount of water was set to 350 kg or more and 400 kg or less in 1 m ³ of the total capacity of the mortar.
If the amount of water is constant, decreasing the amount of cement improves the fluidity of the mortar and reduces the specific gravity, but the strength of the cured product is reduced. Further, when the amount of water is constant, if the amount of cement is too much, the strength is improved, but the flowability of the mortar is deteriorated, and the specific gravity is increased, so that it becomes heavy. Therefore, the blending amount of cement was set to 640 kg or more and 680 kg or less in 1 m ³ of the total volume of the mortar.
The blending amount of the remaining aggregate is, for example, about 420 kg or more and 485 kg or less in a total volume of 1 m ^{3 of the} mortar, although it depends on its specific gravity.
The mortar of the present invention having the above composition has a specific gravity of about 1.5 and is lightweight. Moreover, it has a good fluidity of 15 cm or more as a flow value with a mortar cone.

The mortar of the present invention may have a composition containing 390 kg to 400 kg of water, 640 kg to 660 kg of cement, and 80 kg to 120 kg of a curing accelerator (hereinafter referred to as this composition) in a total volume of 1 m ^3. The type of mortar is also called “quick hardening type”).
The more the accelerator is used, the shorter the time required to cure the mortar, but the workability deteriorates. Therefore, the blending amount of the curing accelerator is set to 80 kg or more and 120 kg or less in 1 m ³ of the total volume of the mortar.
In this quick-hardening type mortar, the amount of the remaining aggregate is, for example, about 420 kg or more and 440 kg or less in the total volume of 1 m ^{3 of the} mortar, depending on the specific gravity.
The rapid hardening type mortar according to the present invention has rapid hardening within 5 hours required to reach a practical strength of 5 N / mm ² or more.

Alternatively, the mortar of the present invention may have a composition containing the water of 350 kg or more and 360 kg or less and the cement of 660 kg or more and 680 kg or less in a total volume of 1 m ³ (hereinafter, the mortar type of this composition is referred to as “early” Also called “strong type”).
In this early-strength type mortar, the amount of aggregate in the remaining amount is, for example, about 455 kg or more and 485 kg or less in a total volume of 1 m ^{3 of the} mortar, although it depends on its specific gravity.
The early strength type mortar according to the present invention has early strength within 12 hours required to reach a practical strength of 5 N / mm ² or more.

  In the mortar of the present invention, hard pearlite can be suitably used as the lightweight fine aggregate.

The mortar of the present invention may contain 20 kg or more and 50 kg or less of an expanding material in a total volume of 1 m ³ .
The expansion material has a function to compensate for the shrinkage of the mortar during curing. If the amount of the expanded material is too small, the mortar shrinks, and if the amount is too large, it becomes uneconomical. Therefore, the amount of the expanded material is 20 kg or more and 50 kg or less in the total volume of 1 m ^{3 of the} mortar.

The mortar of the present invention may contain a high-performance AE water reducing agent or an AE water reducing agent in an amount of 0.5 wt% to 5 wt% of the total amount of the cement and the expansion material.
The high-performance AE water reducing agent or the AE water reducing agent is blended in order to maintain the fluidity of the mortar, and exhibits its effect within the above blending amount range.

The mortar cured product of the present invention is obtained by curing the mortar of the present invention.
This mortar cured product is light and has a good filling state. In particular, a mortar cured product obtained by curing the rapid-hardening type or early-strong type mortar of the present invention can be quickly cured to obtain practical strength.

The bridge of the present invention is characterized by having a steel floor plate reinforced with the hardened mortar of the present invention.
This bridge is lightweight and has a good filling state of a mortar cured product that is a reinforcing material. In addition, when the mortar cured product is obtained by curing the rapid-hardening type or the early-hardening type mortar of the present invention, the mortar quickly cures to obtain practical strength. Loss can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the mortar which is lightweight and has favorable fluidity | liquidity can be provided. Moreover, according to this invention, the mortar hardened | cured material used as a lightweight and favorable filling state can be provided. Further, according to the present invention, it is possible to obtain a bridge that is lightweight and has a good filling state of a mortar cured product that is a reinforcing material.

Hereinafter, embodiments of the present invention will be described.
Examples of the cement used in the mortar of the present invention include Portland cement. Among them, the early strong Portland cement specified in JIS R 5210 is preferable because the cement itself has early strength.

  Examples of the lightweight fine aggregate used in the mortar of the present invention include pearlite and shirasu balloon. Among them, hard pearlite (pearlite pearlite) having a particle size of 1.2 mm or less is preferable because the aggregate has strength and is easily available.

  Examples of the expanding material used in the mortar of the present invention include a lime-based expanding material and a CSA (calcium sulfoaluminate) -based expanding material. Among them, the lime-based fast-strength expanding material is preferable because it has fast-strength itself.

  As a hardening accelerator used for the mortar of this invention, a basic calcium chloride type hardening accelerator, a calcium aluminate type | system | group early strengthening material, etc. are mentioned. Among these, a basic calcium chloride-based curing accelerator is preferable because it is inexpensive.

  Examples of the high-performance AE water reducing agent and AE water reducing agent used in the mortar of the present invention include polycarboxylic acid-based AE water reducing agents and lignin sulfonic acid compounds. Of these, polycarboxylic acid-based high-performance AE water reducing agents and AE water reducing agents are preferred because they do not have a cement retarding action.

The mortar hardened | cured material of this invention is obtained by leaving still for a fixed time, after filling the desired location with the said mortar of this invention like the normal mortar hardened | cured material.
Since the mortar of the present invention has good fluidity, a self-filling method can be adopted.
The mortar cured product obtained by curing the quick-hardening type mortar of the present invention has a practical strength within about 5 hours after filling. The mortar cured product obtained by curing the early strength type mortar of the present invention has a practical strength within about 12 hours after filling.

  The bridge of the present invention is, for example, a steel plate slab structure comprising a deck plate constituting a floor slab of a traveling road and a plurality of ribs fixed to the lower surface of the deck plate and formed in a closed cross section having an internal space. In the closed cross-sectional space of the rib, the mortar of the present invention is filled and cured.

(Example)
Hereinafter, the present invention will be described in more detail with reference to examples.
Table 1 shows mortar materials used in this embodiment. However, these materials are examples of materials used in the mortar of the present invention, and the present invention is not limited by these materials.

Using the above materials, quick hardening type and early strength type mortar were blended. Table 2 shows the amount of material blended per unit volume of each type of mortar.
Each material was mix | blended in the following procedures.
(1) Stir cement, expanded material, and lightweight fine aggregate with a mixer.
(2) Add water, curing accelerator, and AE water reducing agent.
(3) Stir the whole.
Table 2 also shows the density of the mortar after blending. Table 2 also shows the actual measured values of the mortar breathing rate. As shown in Table 2, neither the rapid-hardening type nor the early strong type mortar caused breathing (water separation).

(Compressive strength test)
The rapid hardening type and early strength type mortar was cast and cured for a predetermined time to obtain a cylindrical specimen having a diameter of 50 mm and a height of 100 mm. In Table 3, the compression strength test result based on JIS A 1108 of the obtained cylindrical specimen is shown for every hardening time.

(Fluidity test)
Regarding the rapid hardening type and early strength type mortar, the flow value immediately after mixing the materials was measured based on the flow test defined in JIS R 5201. Table 4 shows the flow values immediately after removing the flow cone (before applying the falling motion).

(Filling test)
A filling test was performed with a model imitating a U-rib of a bridge shown in FIGS. 1 (a) to 1 (c). 1A is a cross-sectional view of a container used in the filling test, FIG. 1B is a cross-sectional view showing a state in which a transverse gradient is applied to the container, and FIG. 1C is a longitudinal gradient of the container. It is a longitudinal cross-sectional view which shows the state which gave.
The container 10 includes a container body 11 and a lid 12 each made of vinyl chloride. The container 10 has a longitudinal length of about 2.5 m and a volume of about 0.2 m ³ . An inlet 15 for injecting mortar is opened at one end in the longitudinal direction of the bottom of the container body 11, and the other end communicates from the outside of the bottom of the container body 11 to the vicinity of the top inside the container body 11. An open outlet 16 is provided.
The container 10 was provided with the longitudinal gradient and the transverse gradient shown in Table 5 and filled by injecting mortar from the injection port 15. The mortar flow value and pumping speed are also shown in Table 5. In this test, early mortar types shown in Table 2 are used. Numbers 1 and 2 and numbers 3 and 4 have the same composition, but numbers 2 and 4 are about 1 hour after mixing. The test was conducted after the passage of time and the flow value was lowered.

  Immediately after filling the container 10 with mortar, the voids were visually confirmed. In all the samples, small voids remained, but no large voids causing problems occurred. Therefore, it was confirmed that the mortar of the present invention can be filled well.

It is a figure which shows the container used for the filling test in an Example, (a) is a cross-sectional view of a container, (b) is a cross-sectional view which shows the state which gave the cross gradient to the container, (c) is a longitudinal section in a container It is a longitudinal cross-sectional view which shows the state which gave the gradient.

Explanation of symbols

10 container 11 container body 12 lid 15 inlet 16 outlet

Claims (8)

During the entire capacity 1m ^3,
350 kg or more and 400 kg or less of water,
640 kg or more and 680 kg or less of cement;
A mortar containing a remaining amount of aggregate,
A mortar characterized in that the aggregate consists essentially of a lightweight fine aggregate having a particle size of 1.2 mm or less and a specific gravity of 1.3 or less. During the entire capacity 1m ^3,
390 kg to 400 kg of water,
640 kg or more and 660 kg or less of the cement;
The mortar according to claim 1, comprising a curing accelerator of 80 kg or more and 120 kg or less. During the entire capacity 1m ^3,
350 kg or more and 360 kg or less of the water,
The mortar according to claim 1, comprising 660 kg or more and 680 kg or less of the cement.   The mortar according to any one of claims 1 to 3, wherein the lightweight fine aggregate has hard pearlite. During the entire capacity 1m ^3,
The mortar according to any one of claims 1 to 4, comprising 20 kg or more and 50 kg or less of an expanding material.   The high-performance AE water reducing agent or AE water reducing agent is contained in an amount of 0.5 wt% to 5 wt% of the total amount of the cement and the expansion material. Mortar.   A mortar cured product obtained by curing the mortar according to any one of claims 1 to 6.   A bridge comprising a steel floor reinforced with a hardened mortar according to claim 7.

Images