JP2008230890A - Grout or mortar material - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide grout and a mortar material, the drying shrinkage, autogenous shrinkage and shrinkage quantity of each of which can be reduced without using an expanding agent and a shrinkage reducing agent and each of which gives satisfactory compressive strength and is inexpensive since the expanding agent and the shrinkage reducing agent are not used. <P>SOLUTION: The grout or the mortar material is composed of limestone particles and cement. The limestone particles have 0.15-2.5 mm particle size and account for ≥50% of the solid content volume. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a grouting or mortar used for seismic reinforcement work in the field of civil engineering construction, machine foundation, steel frame / steel column base, ground injection, tunnel lining back, shield segment back filling, joint filling, etc. It relates to materials.

  Grout and mortar are used for adhesion and filling with existing structures, so high fluidity and low shrinkage are required. In general, the amount of water required for obtaining fluidity increases. In addition, the material particles used for the material that fills the thin gap and the material that is applied thinly must have a small particle size. In order to obtain high fluidity using a material having a small particle size, it is necessary to increase the amount of water.

  For these reasons, grout and mortar are generally formulated with a large amount of water, resulting in large drying shrinkage. Further, when the amount of water is reduced and the water cement ratio is reduced, the drying shrinkage can be reduced, but the self-shrinkage is increased, and as a result, the amount of shrinkage is not reduced.

Large shrinkage causes problems such as cracking in grout and mortar, and obstructing adhesion to existing structures. In order to solve these problems, an expansion material and a shrinkage reducing agent are used. However, these are expensive, but the expansion material is difficult to control expansion, and there is a risk of excessive expansion. The shrinkage reducing agent has problems such as a decrease in strength such as inhibiting the hardening of cement or increasing the entrainment of air (see, for example, Patent Document 1).
JP 2004-345898 A

  The present invention has been made in view of such circumstances, and without using an expansion material or a shrinkage reducing agent, drying shrinkage and self-shrinkage are reduced, the amount of shrinkage is reduced, and sufficient compressive strength is obtained. An object of the present invention is to provide a grouting material and a mortar material which are low in cost since no expansion material and shrinkage reducing agent are used.

  According to the present invention, a grout or mortar material comprising limestone particles and cement, wherein the limestone particles having a particle size of 0.15 to 2.5 mm occupy 50% or more of the solid volume. Or a mortar material is provided.

  The grout or mortar material according to the present invention can obtain a sufficient compressive strength and reduce the amount of shrinkage. In addition, there is an excellent effect that it can be manufactured at low cost without requiring an expensive expansion material or shrinkage reducing agent.

  Hereinafter, embodiments of the present invention will be described in detail. The type of cement used in the present invention is not particularly limited, and examples thereof include various Portland cements such as ordinary Portland cement, early-strength Portland cement, moderately hot Portland cement, low heat Portland cement, blast furnace cement, fly ash, and the like. Mixed cements such as cement and silica fume cement can be used.

Limestone particles are used as the fine aggregate used in the present invention, and the particle size of the fine aggregate is preferably 0.15 mm to 2.5 mm. In order to obtain a grout material excellent in horizontal fluidity and gap filling property, the maximum particle size of the fine aggregate is preferably 2.5 mm or less. In addition, when a particle having a particle size of less than 0.15 mm is used, the consistency required for a grout cannot be obtained, which is inappropriate.

In the grout and mortar materials of the present invention, it is necessary that limestone particles having a particle size of 0.15 to 2.5 mm occupy 50% or more of the solid content volume. The solid content volume means the total volume of the solid excluding the liquid among the materials used for the grout and mortar materials of the present invention.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

1.
Materials used Cement: Ordinary Portland cement (manufactured by Taiheiyo Cement)
Limestone A: Limestone particles with a particle size of 0.15 to 2.5 mm and water absorption of 0.6% Mineral sand: Mineral sand particles with a particle size of 0.15 to 2.5 mm and water absorption of 0.8% River sand: Particle size River sand particles with 0.15-2.5 mm and water absorption rate of 1.6% Blast furnace slow cooling slag: Particle size of 0.15 to 2.5 mm, blast furnace slow cooling slag with water absorption rate of 1.4% Limestone F: Particle size Limestone particles of 0.15 mm or less For any fine aggregate (excluding limestone F), the particle size of 0.15-0.3 mm is 20%, 0.3-0.6 mm is 60%, 0.6- 1.2 mm was 15% and 1.2 to 2.5 mm was 5%.

2. Test method Ordinary Portland cement, fine aggregate, and water were kneaded with the formulation shown in Table 1 to obtain a grout (mortar). In addition, the grout (mortar) consistency for kneading was added with a high-performance water reducing agent in an amount necessary for a flow-down time of 8 ± 1 seconds in the J14 funnel test.

3. Measurement of shrinkage Drying shrinkage was measured according to JIS A 1129. For details, place the mixed grout on a 10 × 10 × 40 cm prismatic steel formwork, cure in a 20 ° C room with a vinyl sheet so that the surface does not dry, and then remove the mold. . The base length was measured immediately, and then placed in a room at 20 ° C. and a humidity of 65 ± 5% RH until the age of 28 days, and the amount of shrinkage was determined by measuring the change in length. The measurement was performed by the dial gauge method. The results are shown in Table 1.

4). Measurement of compressive strength Grout (mortar) kneaded for shrinkage measurement was placed in a 5 × 10 cm cylindrical steel mold according to JIS A 1108, cured at 20 ° C. for 24 hours, and then demolded. Measurement was carried out under water until 28 days. The results are shown in Table 1.

5. Test results From the results shown in Table 1, when Sample 2 and Samples 4, 5, and 6 and Sample 3 and Sample 5 having the same composition of grout are compared, Samples 2 and 3 that are examples of the present invention have the same particle size. It can be seen that the amount of shrinkage is smaller than those of Samples 4, 5, 6, and 7 containing the same particles at the same rate. Therefore, it turns out that the particle | grains of a limestone are preferable for reduction of shrinkage | contraction amount. Further, comparing Sample 2 and Sample 4, Sample 6, Sample 7, and Sample 3 and Sample 5 with the same proportion of fine aggregate, it can be seen that Sample 2 and Sample 3 according to the present invention have higher compressive strength. . However, even when limestone particles are used, when the particles having a particle size of less than 0.15 mm are used, the necessary consistency as a grout cannot be obtained, which is inappropriate. If the particle size is increased, the consistency can be improved, but there is a limit to the grout material used in a narrow place, and the maximum particle size must be 2.5 mm or less. In addition, it does not mean that a single particle having a particle size of 2.5 mm or more should not be mixed, but mixing of about 5% is allowed if the particle size is 2.5 to 5 mm. Similarly, about 10% of particles of 0.15 mm or less are allowed.

Moreover, 50% or more of a solid content volume is preferable for the blending of limestone particles having a particle size of 0.15 to 2.5 mm. Sample 9 in Table 1 has a blending ratio of limestone particles having a particle size of 0.15 to 2.5 mm of about 47% of the solid content volume and sufficient compressive strength, but the shrinkage is smaller than that of Sample 1. Large, sufficient shrinkage reduction effect does not appear. Therefore, by making the limestone particles having a particle size of 0.15 to 2.5 mm 50% or more of the solid content volume, it is possible to reduce the same amount of shrinkage without using an expansion agent and a shrinkage reducing agent. In terms of compressive strength, it is possible to obtain a compressive strength higher than that when an expansion agent and a shrinkage reducing agent are used.

Claims (1)

  A grout or mortar material comprising limestone particles and cement, wherein the limestone particles having a particle size of 0.15 to 2.5 mm occupy 50% or more of the solid content volume.