JPH07172957A - Mortal laminated to alc board - Google Patents

Abstract

PURPOSE:To reduce the generation of cracks in an ALC board in a process for hardening a mortal by laminating a specific mortal, when the mortal in a considerable thickness is laminated to the ALC board as a floor board. CONSTITUTION:In the conventional technique for finishing a floor, a mortal is laminated in a thickness of maximum 15 mm to an ALC board. But, when the rigidity or sound insulation of the floor is enhanced, the mortal is laminated in a thickness of >=15mm. When a conventional mortal is used, the hardened product of the mortal is contracted by the evaporation of water on the hardening of the mortal. Especially, in a process for hardening the mortal on the ALC board, the ALC board is warped, and cracks are sometimes generated between reinforcing steel layers and other layers in the ALC board. For solving theme, a mortal comprising 100 pts.wt. of sand, 15-25 pts.wt. of high early strength Portland cement, 5-15 pts.wt. of spherical fly ash, 0.5-2.5 pts.wt. of polypropylene glycol having a mol.wt. of 100-800, 2.5 pts.wt. of an expanding agent (e.g. containing unslaked lime and calcium sulfoaluminate as main components), and water is used.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the composition of laminated mortar for ALC boards, especially ALC boards used for floors.

[0002]

BACKGROUND OF THE INVENTION The use of ALC boards for building floors is well known in the art. It is also known that one of the finishing construction methods for the floor is to stack mortar on the ALC plate with a maximum thickness of 15 mm {"Construction Standard Specification / JASS
21 ", p. 119 (1989, Architectural Institute of Japan)}. A so-called ordinary mortar is used as the mortar.

[0003]

When it is desired to increase the rigidity of the floor itself or to improve the sound insulation, it is necessary to make the thickness of the mortar more than 15 mm. When the mortar hardens, the cured mortar shrinks due to water evaporation. Since the ALC plate and the cured product are in close contact with each other, a force for contracting the ALC plate is generated in the cured product when the cured product contracts. This force increases as the thickness of the mortar increases. Therefore, there is a problem that the ALC plate warps in the process of hardening the mortar on the ALC plate, and in some cases, cracks occur between the reinforcing bar layer and other layers in the ALC plate. Therefore, an object of the present invention is to provide a mortar composition capable of suppressing cracking of an ALC plate even if the mortar is laminated on the ALC plate as a floor plate so as to have a thickness larger than that of the prior art.

[0004]

In order to solve the above-mentioned problems, the invention of claim 1 is based on 100 parts by weight of sand. 15-25 parts by weight of early strength Portland cement and 5-15 parts by weight of spherical fly ash. Part, 0.5 to 2.5 parts by weight of polypropylene glycol having a molecular weight of 100 to 800, and water. In order to solve the above-mentioned problems more efficiently, the invention of claim 2 is based on 100 parts by weight of sand, 15 to 25 parts by weight of early strength Portland cement, 5 to 15 parts by weight of spherical fly ash, and 100 to 100 parts of molecular weight. 80
0.5 to 2.5 parts by weight of polypropylene glycol of 0,
A mortar containing 2.5 parts by weight or less of an expanding agent and water.

[0005]

In the invention of claim 1, the early-strength Portland cement has less shrinkage than the ordinary Portland cement in the course of hardening of the mortar. Spherical fly ash uses less water than mortar where it is not used. The smaller the amount of water used, the more the shrinkage of the mortar is reduced. Polypropylene glycol is soluble in water and lowers the interfacial tension of water, so when the mortar becomes a cured product, it enters the fine gaps of the cured product and remains in the gaps of the cured mortar, compared to the case where only water is present. Suppresses mortar shrinkage.

According to the second aspect of the present invention, the expanding agent slightly expands the mortar in the initial stage of hardening the mortar.
The amount of the expansion reduces the shrinkage of the mortar.

[0007]

Next, one embodiment embodying the present invention will be described in detail. First, a mortar raw material is prepared. The sand used in this example is river sand, which is a fine aggregate having a coarse grain ratio of 2.92 shown in Table 1 according to JIS A1102.

[0008]

[Table 1]

JIS as early strength Portland cement
The cement prescribed by R5210 (manufactured by Onoda Cement Co., Ltd.) is a fly ash having a mean particle size of 6 microns as spherical fly ash {trade name: ONODA Super Flow (manufactured by Onoda Cement Co., Ltd.)}, and as polypropylene glycol. Each diol having an average molecular weight of 450 was prepared.

Then, the above raw materials were mixed with water in a mixing ratio shown in Table 2 to prepare a mortar of this example. The fluidity of this mortar immediately after kneading is measured according to JIS R52.
170m when measured by the method specified in 01
A flow value of m × 170 mm was obtained.

[0011]

[Table 2]

The mortar prepared as described above was subjected to ALC.
A known floorboard using a board, for example, JP-A 1-2308
A floor structure was formed by placing the floor plate disclosed in Japanese Patent Laid-Open No. 42-42 so as to have a thickness of 40 mm. After a lapse of 24 hours, a plurality of pairs of gauges for measuring dimensional change {two-point distance measuring gauge manufactured by Marui Co., Ltd. (trade name: Whitmore)} are set on the surface of the cured laminate on the ALC floor plate, and 2
It was measured how the distance between points changed over time. And the average value of the length change between each gauge was calculated.
The results are shown in the figure. As is clear from the figure, even after 40 days, only a length of 0.1 mm per unit length (1 m) of the laminate contracted.

[0013]

[Comparative Example] For comparison, as a raw material in the above-mentioned Examples, ordinary Portland cement was used instead of early-strength Portland cement, and river sand with a coarse grain ratio of 2.50 used for ordinary mortar was used instead of river sand in Examples. I prepared. Then, without using spherical fly ash and polypropylene glycol, ordinary mortar was prepared from the cement, river sand and water in the mixing ratio shown in Table 3. The flow value of this mortar is 173mm × 172mm
Met.

[0014]

[Table 3]

This mortar was subjected to ALC in the same manner as in the above embodiment.
It was cast on a plate and its dimensional change was measured. The results are shown in the same figure as the above-mentioned embodiment. As is clear from the figure, the dimensional change of the mortar of the comparative example was significantly worse than that of the example.

The present invention is not limited to the embodiment described above, but a part of the embodiment can be modified as follows. (1) A mortar or a concrete expander may be added to the raw materials of Examples in an amount of 2.8 parts by weight or less, preferably 0.5 to 2.5 parts by weight, based on 100 parts by weight of sand. it can. If it exceeds 2.8 parts by weight, the mortar cured product itself will crack due to mortar expansion. As a swelling agent, quicklime and calcium sulfaluminate are preferable because they react with water in the mortar to exhibit swelling properties.

(2) The mixing ratio of the early-strength Portland cement can be changed to 15 to 25 parts by weight with respect to 100 parts by weight of sand. If the amount is less than 15 parts by weight, the strength of the cured mortar cannot be maintained above a predetermined level, and conversely, if the amount exceeds 25 parts by weight, shrinkage of the cured product becomes large. (3) The compounding ratio of spherical fly ash is 5 to 5 as in the above.
It can be changed within the range of 15 parts by weight. If it is less than 5 parts by weight, the predetermined flow value cannot be maintained. The flow value can be maintained within a predetermined range by increasing the amount of water, but in this case, the contraction becomes large. When it exceeds 15 parts by weight, the strength of the cured mortar is lowered.

(4) When the compounding ratio of polypropylene glycol is less than 0.5 parts by weight, the effect of reducing shrinkage is not exhibited, and when it exceeds 2.5 parts by weight, the strength cannot be maintained at a predetermined value. (5) The mixing ratio of water can be changed so as to have a predetermined flow value. The normal flow value is 140 to 200 as a guide.
The flow value is determined in consideration of work efficiency when forming the laminate. (6) When the thickness of the mortar laminate is made larger than that of the prior art, the present invention exerts its effect remarkably. In the present invention, the thickness of the cured mortar can be increased to 50 mm.

[0019]

As described in detail above, when the mortar according to the present invention is laminated on an ALC plate as a floor plate with a considerable thickness, it is possible to suppress cracking of the ALC plate during the curing process of the mortar. The present invention exerts the effect.

[Brief description of drawings]

FIG. 4 is a diagram showing a change in length of a mortar laminate with time.

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Claims (4)

[Claims] 1. 15 to 25 parts by weight of early-strength Portland cement and 5 spherical fly ash to 100 parts by weight of sand.
~ 15 parts by weight, 0.5-2.5 parts by weight of polypropylene glycol having a molecular weight of 100-800 and water and AL
Mortar for C plate. 2. 15 to 25 parts by weight of early-strength Portland cement and 5 parts of spherical fly ash to 100 parts by weight of sand.
A mortar for an ALC plate comprising ˜15 parts by weight, 0.5 to 2.5 parts by weight of polypropylene glycol having a molecular weight of 100 to 800, 2.5 parts by weight or less of an expanding agent, and water. 3. The mortar for an ALC plate according to claim 2, wherein the main components of the expanding agent are quicklime and calcium sulfaluminate. 4. The A according to claim 1 or 2, wherein the sand has a coarse grain ratio of 2.8 or more according to JIS A1102.
Mortar for LC plate.