JPH08136486A - Quick determination of unit quantity of cement and water-cement ratio in slurry discharged by cement jetting injection - Google Patents

Abstract

PURPOSE: To quantitatively determine the unit quantity of cement in a slurry quickly by carrying out wet-screening for a discharged slurry and dissolving the cement in a prescribed amount of obtained mortar in a cation exchange resin. CONSTITUTION: A slurry of cement silk used for soft ground stabilization work and discharged by jetting infection is sampled and wet-screening of the slurry is carried out. The obtained mortar is poured in an one litre beaker and stirred, and then 2.00g of the mortar is weighed, taken, and put in 100ml beaker and 50ml distilled water is added to the mortar. To the obtained mortar slurry, 20g of H-R washed by distilled water and filtered at decreased pressure is added, and while being stirred, the resulting slurry is left to completely dissolve cement in the mortar. On the completion of stirring, the slurry is filtered and the electric conductivity of the filtered liquid is measured and in the case the measured values are put in Y-axis and planed unit cement quantities are put in X-axis, a linear relation is found between the values and the quantities. Consequently, a unit cement quantity can be quantitatively measured only by measuring the electric conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for rapidly determining the amount of cement in a cement-containing material and the water-cement ratio, and more specifically, a slurry discharged by injection injection of cement milk used in soft ground improvement work. The present invention relates to a determination method capable of quantifying the amount of unit cement in the cement-containing material and measuring the water-cement ratio quickly and easily.

[0002]

2. Description of the Related Art Conventionally, there are JSG method (FIG. 5), column jet grout method (FIG. 6) and the like as injection injection method, which are widely used for ground improvement and water stoppage. Basically, it is a construction method in which water, cement milk, a chemical solution, and in some cases, air is jetted at the same time as water to crush the ground, and the ground is hardened with a solidifying material such as cement milk.

The column jet grouting method as a typical example of the method is to artificially reach the ground by ejecting ultrahigh pressure water accompanied by air while rotating the ground to cut the ground and discharge the slime to the surface of the ground. This is a construction method in which a space is created and a solidified material is simultaneously filled in it to form a columnar solidified body.

According to this method, a solidified body having a diameter of about 2 m can be formed with a hole having a diameter of about 15 cm, a mechanical device is relatively simple, and the target soil can be applied to any ground except a boulder layer. Since it has many advantages, it is widely used for ground improvement.

A large amount of cement is contained in the slurry discharged and discarded by the injection pouring method using cement milk as a solidifying material used in soft ground improvement work and the like. Therefore, there is a strong desire from the viewpoint of effective utilization of resources, construction cost, etc. to establish a technology for reuse by quantifying the unit cement amount in the slurry and measuring the water cement ratio quickly and simply. There is.

[0006]

DISCLOSURE OF THE INVENTION The present invention provides a quick and simple method for quantifying the amount of cement in a slurry discharged by a jet injection method using cement milk used for improving soft ground and for measuring the water-cement ratio. It proposes a method to do.

[0007]

The present invention was developed in view of the above situation, that is, it was obtained by wet screening the cement-containing material in the slurry discharged by cement injection injection. A predetermined amount of mortar or soil cement is sampled, the cement in the mortar is melted with a cation exchange resin, and then the electrical conductivity in the solution is measured to determine the unit amount of cement in the cement-containing material. The present invention proposes a rapid method for determining the amount of unit cement in a cement-containing material and the water-cement ratio, which is characterized by determining the water-cement ratio.

The present invention, which is configured as described above, is capable of quantifying the amount of unit cement in the slurry discharged by the cement injection injection method and measuring the water cement ratio quickly and easily. Hereinafter, test examples and examples of the present invention will be described.

Test Example 1 (Quantification of Unit Cement Amount) The materials used in this Test Example 1 and the test method therefor are as follows. (A) Materials used: As cement used for ground improvement,
About 90% or more of the cement currently used is Portland cement,
The cement was tested, and as the ion exchange resin, Dowex 50W × 4 (200-
A 400-mesh H-type strongly acidic cation exchange resin (hereinafter, simply referred to as HR) was used.

(B) Test method: About 2 liters of soil cement was wet-screened with a 5 mm sieve to obtain mortar. The mortar was placed in a 1 liter beaker and sufficiently stirred, then 2.00 g was precisely weighed and sampled to obtain 100 ml. It was placed in a beaker and 50 ml of distilled water was added with a pole pipette.

H was washed with distilled water and then filtered under reduced pressure.
-R20g was added and left for 15 minutes with occasional stirring to completely dissolve the cement in the mortar. next,
After completion of stirring, this was filtered, and the electric conductivity (hereinafter, referred to as K) of the obtained filtrate was measured.

(C) Regarding test results: The measured values of [K] obtained by the above test method are shown in FIG. 1 with the Y axis as the planned unit cement amount [C] on the X axis. As can be seen from FIG. 1, [K] (ms / cm) and the planned unit cement amount [C] (kg / M ³ ) show a linear relationship, and the relationship between the two can be expressed by the following equation (1). it can. [K] =-0.0935 + 0.0046 [C] (1)

The variation in this case is ± 5% of the equation (1).
Was within the range (inside the dotted line in FIG. 1). It was thought that the cause of this variation was how to collect 2.00 g of mortar, so the results of repeated sampling from the same sample showed that
Since [K] is a variation within the range of about 0.1 (ms / cm), this is well within the error range.

Further, the relationship between the estimated unit cement amount and the planned unit cement amount is shown in FIG. 2, and the relationship between them is within ± 5% (within the dotted line in FIG. 2).

From the above test results, the unit cement amount (k
It was found that g / M ³ ) can be quantified only by the measured value of electric conductivity [K].

Test Example 2 (Measurement of Water Cement Ratio) The materials used in Test Example 2 and the test method therefor are as follows. (D) The materials used are the same as in Test Example 1. (E) Test method: a) About 2 liters of soil cement was wet-screened with a 5 mm sieve to obtain mortar. The mortar was placed in a 1 liter beaker and sufficiently stirred, and then 2.00 g was precisely weighed and sampled, and a 100 ml beaker. Then, 50 ml of distilled water was added with a pole pipette.

H was thoroughly washed with distilled water and filtered under reduced pressure.
-R20g was added and left for 15 minutes with occasional stirring to completely dissolve the cement in the mortar. After completion of stirring, the electric conductivity [K] of the filtrate obtained by filtering this was measured.

Obtained [K] measurement value and mortar 2.00
FIG. 3 shows the relationship with the amount of cement in g, and from this, the amount of cement [B] in 2.00 g of mortar can be determined.

B) Next, similarly to the above a), 20.00 g is accurately weighed from a well-stirred mortar obtained by wet screening with a 5 mm sieve, sampled in a 200 ml beaker, dried for 15 minutes, and dried. After that, weigh it and measure the mass [M] of the mortar.

C) Next, the mass [G] of the fine aggregate in 2.00 g of mortar was determined by the above a) and b) [A], [B].
And the water absorption rate (%) [q] (specific value) of the fine aggregate,
It is calculated by the following equation (2).

D) Next, the water-cement ratio [W / C] is obtained from the relational expression (3) from the [A], [B], [G] and [q] obtained as described above.

(F) Test results: When the water-cement ratio is measured without correction, it is 10% higher than the planned water-cement ratio. The reason for this is that the amount of water in soil cement increases due to wet screening, and the water-cement ratio [W /
It is considered that C] became higher.

Therefore, the result calculated by adding the correction term (-10) as shown in the equation (3) is shown in FIG. 4 as a relationship between the estimated water cement ratio and the planned water cement ratio. It can be seen that the relationship between the two is almost the same within the range of ± 3% (dotted line in the figure).

Around the water-cement ratio [W / C] = 60%, the soil cement was soft, and therefore some variation was observed. Therefore, when mortar was sampled three times from the same sample and a judgment test was conducted, the water-cement ratio was ± 1.
It could be judged within the range of 2%.

From the above results, it has been found that the water-cement ratio can be determined with relatively high accuracy, quickly and easily.

[0026]

【Example】

Example 1 Slurry discharged from the site during construction of the injection injection method using cement milk as a solidifying material in the soft ground work of Company B was sampled, and the unit amount of cement was quantified by the same method as in Test Example 1 above. Then, the water-cement ratio was measured in the same manner as in Test Example 2.

As a result, the unit cement amount (Kg / M ³ )
Can be quantified only by the measured value of electrical conductivity [K].
The cement ratio could be measured with relatively high accuracy, quickly and easily.

[0028]

EFFECTS OF THE INVENTION According to the present invention, the quantitative determination of the unit cement amount and the water-cement ratio of the cement-containing material such as the slurry discharged from the injection injection method using cement milk as the solidifying material in the soft ground improvement work etc. The measurement can be performed quickly and easily.

Further, according to the present invention, the time required for the measurement is about 30 minutes for both, and since the measurement can be performed easily and easily without requiring a special device or skill, it is possible to perform the measurement on site. There are many advantages such as that quality control before placing fresh concrete can be sufficiently performed and that soil cement slurry discharged from soft ground improvement work can be reused.

[Brief description of drawings]

[Fig. 1] Electric conductivity [K] and planned unit cement amount [C]
It is a graph which shows the relationship with.

FIG. 2 is a graph showing the relationship between the estimated unit cement amount and the planned unit cement amount.

FIG. 3 is a graph showing the relationship between electrical conductivity [K] and the amount of cement in 2 g of mortar.

FIG. 4 is a graph showing the relationship between the estimated water cement ratio and the planned water cement ratio.

FIG. 5 is a schematic explanatory diagram of a JSG method related to a jet injection method.

FIG. 6 is a schematic explanatory view of a column jet grout method related to a jet injection method.

[Explanation of symbols]

 1-Sand Pump or Vacuum Vehicle 2-Slime 3-Guide Hole (Casing Rod) 4-Drilling Diameter 5-Double Pipe 6-Triple Pipe 7-Compressed Air 8-Ultra High Pressure Water 9-Ultra High Pressure Hardener 10-Hardener 11-feather bit

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadashi Nishino 694 Hiro Hakamacho, Machida City, Tokyo (72) Inventor Katsumi Kodama 2-5-6 Nishinogawa, Komae City, Tokyo (72) Inventor Makio Yahiro Tokyo 4-17-7 Nishisugamo, Toshima-ku, Tokyo (72) Inventor Kiyosasa 1-8-3-101 Yamato, Shizuoka-shi, Shizuoka

Claims (4)

[Claims] 1. Cement-containing material in a slurry discharged by injection injection of cement is wet-screened, a predetermined amount of the obtained mortar is sampled, and the cement in the mortar is dissolved with a cation exchange resin. A method for rapid determination of the amount of unit cement in a slurry discharged by cement injection injection, which comprises quantifying the amount of unit cement in the cement-containing material by measuring the electrical conductivity in the solution. 2. A predetermined amount is sampled from a cement-containing material in a slurry discharged by injection injection of cement, and 5
After thoroughly agitating the mortar obtained by wet screening with a mm sieve, a predetermined amount of the mortar was precisely weighed, sampled, washed thoroughly with water, and filtered under reduced pressure to obtain an H-type strong acidic cation exchange resin in an amount of 10 A double amount is added, and the mixture is stirred, allowed to stand for a predetermined time and then filtered, and the electric conductivity [K] of the obtained filtrate is measured, and the relational expression between the electric conductivity [K] and the unit cement amount [C] [ K] =-0.0935 + 0.0046 [C] The unit cement amount [C] is rapidly quantified, and the rapid determination method of the unit cement amount in the slurry discharged by cement injection injection. 3. Cement-containing material in a slurry discharged by injection injection of cement is wet-screened, a predetermined amount of the obtained mortar is sampled, and the cement in the mortar is dissolved with a cation exchange resin. A method for rapid determination of the water-cement ratio in a slurry discharged by cement injection injection, which comprises determining the water-cement ratio in the cement-containing substance by measuring the electric conductivity in the solution. 4. A predetermined amount is sampled from the cement-containing substance in the slurry discharged by cement injection injection, and 5 m
After stirring the mortar obtained by wet screening with m sieve, 200 g was precisely weighed and sampled, and H-type strongly acidic cation exchange resin which was sufficiently washed with water and filtered under reduced pressure was added in an amount 10 times the amount of the mortar. Was added and stirred, and then filtered, and the mortar was obtained by the relational expression [K] = 0.065 + 3.293 [B] between the electric conductivity [K] of the obtained filtrate and the amount [B] of cement in 2.00 g of mortar. Or soil cement milk 2.00
The amount of cement [B] in g was determined, and then 20.00 g was precisely weighed after thoroughly stirring the mortar or soil cement milk obtained by wet screening with the above 5 mm sieve, and in a prescribed container for a prescribed time. After drying, the amount of water [A] in 2.00 g of the mortar or soil cement was determined by measuring the mass [M] of the mortar or soil cement milk, and the water absorption rate of the fine aggregate in 2 g of the mortar was calculated. (%) [Q]
And the above [A] and [B] The mass [G] of the fine aggregate in 2 g of mortar or soil cement is calculated by the following formula, and the relational expression is calculated from the above [A], [B], [G] and [q]. A rapid method for determining a water-cement ratio in a slurry discharged by cement injection injection, which is characterized by rapidly measuring a water-cement ratio [W / C].