JP2867088B2 - Underwater mortar - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to underwater mortars, and more particularly to underwater mortars used to construct underwater structures.

[0002]

2. Description of the Related Art Underwater mortars have conventionally been cast when constructing underwater structures such as foundation piles and footings. To the underwater mortar, a water-immiscible admixture is added so that the respective materials mixed in the water during casting are not separated, and a high-performance water reducing agent is added to ensure its fluidity. . Therefore, the action of the admixture delays the development of the strength of the mortar in water, and even when an early-strength cement or an early-strength admixture is used, for example, 30 kgf / cm ² in one day of age and two days in age of two days. 200kgf / cm ²
Only a degree of strength can be obtained.

[0003]

However, in the above-mentioned conventional underwater mortar, when these are used to construct an underwater structure, for example, a pile foundation, for which it is desired to develop strength immediately after the casting, the underwater mortar is cast. The pile must be fixed using a crane ship or the like until the underwater mortar reaches the specified strength. Therefore, it is necessary to fix the piles for a long time, and there is a problem that the usage fee of the crane ship or the like increases, the construction cost increases, and the construction period is prolonged.

Accordingly, the present invention has been made in view of the above-mentioned problems, and it is possible to develop a predetermined strength in a short time after casting while maintaining the inseparability and fluidity of mortar in water. It is intended to provide a mortar in water.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and the gist of the present invention is to provide an underwater mortar using blast furnace cement, wherein the underwater mortar comprises a rapid-hardening admixture, a setting modifier and Mortar in water, characterized by containing

[0006] Here, the underwater mortar using blast furnace cement is a mortar using blast furnace cement as a cement component, and is a mortar having water inseparability that does not cause material separation in water.

Hereinafter, the present invention will be described in more detail.

The underwater mortar according to the present invention is a mortar containing blast furnace cement, water and fine aggregate, wherein the mortar in water is blended with a rapid-hardening admixture and a setting modifier.

The underwater mortar of the present invention comprises, for example, blast-furnace cement, water, fine aggregate, a rapid-hardening admixture, a setting modifier, a water-immiscible admixture, and a water-immiscible admixture. It is preferred to be constituted by an auxiliary agent.

Here, as the blast furnace cement used in the underwater mortar of the present invention, for example, blast furnace cements A, B, C and the like shown in JISR 5211 "Blast furnace cement" are used.

The water and fine aggregate used are those usually used as concrete materials. And
The amount of water added to the underwater mortar is preferably 50 to 63 parts by weight based on 100 parts by weight of the blast furnace cement used for the mortar. If the amount of water is less than 50 parts by weight, the flow becomes small and it is difficult to cast. If the amount exceeds 63 parts by weight, the strength development is slowed down and the strength is lowered. The amount of the fine aggregate is preferably 100 to 270 parts by weight based on 100 parts by weight of the blast furnace cement. If the blending amount of the fine aggregate is less than 100 parts by weight, the flow becomes small, the viscosity becomes high and the casting becomes difficult, and the material cost becomes high. If it exceeds 270 parts by weight, the strength is lowered. Is also not preferred.

[0012] The rapid-hardening admixture refers to an admixture having an action of promoting the development of strength of the mortar, for example, a cement mineral-based, organic-based, or inorganic salt-based rapid-hardening admixture, preferably calcium sulfoaluminum. Nate-based admixture, more preferably product name "DENCAPRACT-1"
(Manufactured by Denki Kagaku Kogyo) or the like. The amount of the rapid-hardening admixture is preferably 25 to 33 parts by weight based on 100 parts by weight of the blast furnace cement. If the amount is less than 25 parts by weight, the strength development becomes slow, and if the amount is more than 33 parts by weight, the material cost is increased, and neither is preferable.

The above-mentioned setting modifier refers to an admixture which has an action of adjusting the setting time so that the mortar does not rapidly set, and is, for example, a retarder or a long retarder, preferably a product name "Setter" (Electric Co., Ltd.) Chemical industry) is used. The amount of the setting modifier is preferably 0.5 to 0.8 parts by weight based on 100 parts by weight of the blast furnace cement. If the amount is less than 0.5 part by weight, the pot life becomes 60 minutes or less, and if it exceeds 0.8 part by weight, strength development becomes slow and kneading becomes difficult.

The water-immiscible admixture refers to an admixture having an action of preventing the material from being separated by washing with water even when a fresh mortar is poured into water. For example, a cellulosic admixture, preferably a product Use the name "Nissha Ocean SP-12" (manufactured by Nissho Iwai Chemical). The amount of the inseparable admixture is preferably 0.1 to 0.4 parts by weight based on 100 parts by weight of the blast furnace cement. If the amount is less than 0.1 part by weight, the mortar in water separates in water, and if the amount exceeds 0.4 part by weight, the setting time of the mortar in water is lengthened and the strength development is delayed, and the material cost is also increased. Absent.

Further, the water-insoluble sedimentation adjuvant refers to an admixture that enhances the fluidity of the mortar so that it has a lubricating function. For example, a melanin sulfonate-based fluidizer, preferably a product Use the name "UC-150" (manufactured by Pozoris) or the like. The compounding amount of the water-insoluble separable admixture is 100 parts.
It is preferred that the amount be 2.0 to 5.0 parts by weight based on parts by weight. If the addition amount is less than 2.0 parts by weight, the fluidity of the mortar becomes small. Therefore, if the addition amount is more than 5.0 parts by weight, the flow effect does not change and the material cost increases, which is not preferable.

[0016]

The present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0017]

Examples 1 to 5 Blast furnace cement type B, water, fine aggregate, rapid-hardening admixture, setting modifier, insoluble in water admixture, and auxiliary insoluble in water admixture in the proportions shown in Table 1. With respect to the mixed underwater mortars shown in Examples 1 to 5, the material properties obtained by experiments performed in accordance with the “Guidelines for Design and Execution of Underwater Inseparable Concrete (Draft)” by the Japan Society of Civil Engineers are shown in Tables 1 to 5 in Examples 1 to 5. Shown in "Dencaplac-1" (manufactured by Denki Kagaku Kogyo Co., Ltd.)
, Setter (manufactured by Denki Kagaku Kogyo Co., Ltd.) as a coagulant, Nissho Ocean SP-12 (manufactured by Nissho Iwai Chemical) as an inseparable admixture in water, and an insoluble admixture in water "UC-150" (manufactured by Pozzolith) was used as an agent. The material characteristics required for these underwater mortars are that the material has a compressive strength of 30 kgf / cm ² or more in 5 hours of age, a visible time of 60 minutes or more, and has fluidity that can be poured by a pump.

[0018]

[Comparative Example 1] A comparative example in which blast furnace cement B, water, fine aggregate, water-insoluble sedimentation admixture, and water-inseparable admixture adjuvant are mixed in the proportions shown in Table 1 without using an expansive admixture. For the underwater mortar shown in Table 1, material properties obtained by an experiment conducted in accordance with the “Guidelines for Design and Execution of Underwater Inseparable Concrete (draft)” by the Japan Society of Civil Engineers are shown in Comparative Example 1 in Table 2.
Shown in The same water-immiscible admixture and auxiliary water-immiscible admixture as in Examples 1 to 5 were used.

[0019]

[Table 1]

[0020]

[Table 2]

In addition, JIS A110 performed on mortar in water by the blending of Comparative Example 1 and Examples 1 to 5
FIG. 1 shows the test results of the compressive strength test according to No. 8 “Method for testing compressive strength of concrete”.

From the above experimental results, it can be seen that the mortars in water of Examples 1 to 5 according to the present invention have improved properties in order to develop strength at an early stage, and have a predetermined compressive strength of 30 kgf / cm ² after 5 hours of material age. Turns out to be reached.

[0023]

As described above, the mortar-in-water of the present invention is constituted by adding a quick-hardening admixture and a setting modifier to mortar-in-water using blast furnace cement. While maintaining the fluidity and fluidity, the time until these strengths are developed can be greatly reduced. Therefore, by using such underwater mortars, in underwater structures which are required to develop strength immediately after casting, economical underwater structures can be used without using other construction machinery for a long time. Construction can be performed, and the construction period can be shortened.

[Brief description of the drawings]

FIG. 1 is a chart showing test results of a compressive strength test performed on a mortar in water by a combination of Comparative Example 1 and Examples 1 to 5.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Kazuya Miyano 2-5-8 Kitaaoyama, Minato-ku, Tokyo Hazumanai Co., Ltd. (56) References JP-A-5-98643 (JP, A) JP 2-A 17504 (JP, B2) (58) Fields investigated (Int. Cl. ⁶ , DB name) E02D 15/06

Claims (1)

(57) [Claims] 1. An underwater mortar using blast furnace cement as a cement component, wherein the underwater mortar contains a rapid-hardening admixture and a setting modifier.