JPS62288264A - Method for casting hydraulic cement composition - 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] 3. Detailed Description of the Invention'' [Industrial Field of Application] This Q[ relates to a method for placing hydraulic cement compositions (hereinafter referred to as mortars) such as concrete slurry and cement mortar.

[Problem to be solved by the invention 3: According to a recent theory, the strength of mortar after hardening is determined by setting and hardening the amount of water relative to cement near the minimum amount required for hydration of cement. It is said to be extremely strong.

On the other hand, mortars require work such as mixing, pouring, and molding before hardening, and the difficulty of such work, that is, workability, is controlled by the softness, fluidity, viscosity, plasticity, etc. of the mortar. The value had to be appropriate. Conventionally, in order to ensure this workability, it was customary to mix a fairly large amount of water, and it was not easy to put mortar with a low water-to-cement ratio into practical use while maintaining good workability.

The inventor of the present application previously proposed a means for improving the workability of mortars containing the above-mentioned low water cement ratio of 1 to 1 in a patent application published in
It was proposed in No. 299074. This method is a method for producing mortars with a low water-to-cement ratio that uses small ice cubes instead of water. It is characterized by stirring and mixing in the solid state to form a macroscopic homogeneous system, and then gradually transitioning to a homogeneous mixing system as small ice blocks melt, so that substantially all the ice blocks are melted by the time of pouring. .

This manufacturing method has a low water-cement ratio, and even if the amount of small ice blocks added is small, the small ice blocks behave as small blocks with sticky surfaces in a pseudo-solid state, and the surrounding cement, aggregate, etc. By dispersing it in solid particles and mixing for a short period of time dominated by convective mixing, it becomes a macroscopically homogeneous system in which aggregates etc. are evenly dispersed, and then the small ice cubes gradually melt at ambient temperature. The melt water wets the surrounding solids and transitions from a quasi-solid state to a viscous homogeneous composition. Therefore, according to this manufacturing method, even with a low water-cement ratio,
Mortars with high homogeneity can be easily produced. However, even with mortars made using this manufacturing method, it is difficult to provide sufficient fluidity when the water-cement ratio is extremely low, and methods such as pressure molding are required to achieve dense filling. required.

This invention has been made in view of the above-mentioned problems.

The purpose is to propose a mortar pouring method that increases the fluidity of mortar during pouring even at a low water-to-cement ratio and allows for easy and dense sales floor space.

[Means for solving problems]

The method of placing this mortar is cement.

When pouring mortar made of aggregate, water, etc., some of the water is made into small ice blocks and mixed in the mortar, and the temperature of the mortar is raised to O''C0 or higher to gradually melt the small ice blocks, It is characterized by applying vibration to the composition.

When mortar is at rest, the solid particles are interlocked with each other and stable, but when vibration is applied, this interlock separates, reducing resistance to shearing force and promoting fluidization. In this driving method, at the same time as vibration, free water from melting ice blocks is present, and this water loosens the bonding force between solid particles for a short period of time before being finely dispersed and diffused, temporarily fluidizing the mortar. significantly promote. Therefore, compared to the conventional method of pouring mortar with the same water-to-cement ratio, this pouring method improves the fluidity of the mortar during pouring and enables dense filling of the mortar. Note that the free water that contributed to the promotion of fluidization gradually diffuses into the surrounding composition and transforms into a homogeneous system.

The size of the ice cubes used in this driving method is 10 fins or less in diameter. The diameter of the ice cubes at the time of driving is usually about 5 mm or less, and it is necessary to ensure that most of the large number of ice cubes melts and generates free water within a short period of time during the driving process. If the temperature of the mortar or the surrounding environment is relatively high, it is preferable to shift it to the larger diameter side, and if it is lower, it is better to shift it to the smaller diameter side.

The ratio of ice blocks to the total amount of water at the time of implantation is 50% or less. Preferably it is 40% or less. If the amount of water to be pre-kneaded is less than 60% of the total water amount, the fluidity of the base mortar will be poor, and if the amount of ice blocks is 40% or more, it will take a relatively long time to melt, which is not preferable. Furthermore, when the proportion of ice blocks is less than 5%, the effect of promoting fluidization by melt water is poor, and the effect generally decreases. The specific amount and diameter of the ice block are set in consideration of the overall submergence, temperature, driving conditions, etc., so that most of the ice block melts during the driving process.

There are various ways to make mortar used in this driving method. For example, the entire amount of water mixed into mortar (excluding water accompanying aggregates, etc.) is added as ice blocks, and is gradually melted while being mixed with cement, aggregates, etc., until the desired proportion of ice blocks remains and 0. Mortar is prepared in which the ice blocks gradually melt at temperatures above ℃, and this is used for pouring.

Alternatively, some water is mixed to make a hard mortar, and an amount of ice blocks corresponding to the amount of remaining water is added and mixed so that the desired proportion of ice blocks remains and the ice blocks gradually melt. Used for state mortar and pear casting.

The means for applying vibration includes a method using a rod vibrator, a method using a formwork vibrator, etc., and can be selected from conventionally known methods.

The mortar used in this casting method is not limited to one with a low water-to-cement ratio, but the use of mortar in the so-called low-water-to-cement ratio field, where the water-to-cement ratio is 45% or less, is particularly effective.

〔Effect of the invention〕

This invention is as described above. According to this typing method,
Even with mortars with a low water-to-cement ratio, it significantly increases the fluidity of the mortar during pouring, enables dense filling of the mortar, and produces a high-strength cured product with no defects. be able to.

Claims (1)

[Claims] (1) When pouring a hydraulic cement composition consisting of cement, aggregate, water, etc., some of the water is mixed into the composition as small ice blocks, and the temperature of the composition is kept at 0°C or higher. A method for driving a hydraulic cement composition, characterized by applying vibration to the composition while gradually melting ice blocks.