JP4546313B2 - Pile circumference filling liquid - Google Patents

Description

  The present invention relates to a pile circumference filling liquid filled in a pile circumference portion of an existing pile (materials such as steel and concrete are not particularly limited) in order to increase friction with the ground.

  In the construction of pre-made piles, in order to increase the friction between the pile circumference and the ground, the pile circumference is filled with a curable filling liquid. While the required strength of the filling liquid ensures the required strength, not only in terms of functionality and construction, such as excellent frictional properties and filling properties, but also in terms of economics such as the addition of cement and admixtures can be reduced. An excellent filling liquid is desired.

  As a method for increasing the friction with the ground and further improving the bearing capacity of the pile, it is considered effective to give the filling liquid expansion performance. There are described inventions.

  Patent Document 1 describes that about 10% of the total amount of cement milk is mixed with expanded cement (expanded material) in order to give expansion performance to the pile circumference filling liquid.

  In Patent Document 2, a blast furnace slag fine powder mixed with blast furnace slag or ordinary Portland cement is mixed with an anhydrous gypsum of about 2% or less by weight, a thickener such as methylcellulose is added, and water is added. Pile circumference fixing liquid having a cement ratio of about 40 to 80% is described.

In Patent Document 3, as a filling liquid for creating an enlarged bulb portion of a foundation pile, a calcium sulfoaluminate-based expansion material is added to cement paste, and the water / binding material ratio including the expansion material is 65% or less. Is described.
Japanese Patent Publication No. 06-056014 JP 2003-277738 A JP 2000-080647 A

  Conventional pile circumference filling liquid or the like generally uses an expensive material in order to impart expansibility, has a small binder water ratio, and is expensive.

  For example, those described in Patent Documents 1 to 3 described above also use expensive materials such as thickeners and calcium sulfoaluminate (substantially CSA) -based expansion materials, and have a low water / binder ratio, and cement. And a large amount of expansion material. Therefore, the cost is high and the viscosity is high, so that the filling liquid has poor workability.

  The present invention was developed based on such a background, and in the use of an inflatable material having a lower cost while ensuring the strength in terms of friction required as a pile circumference filling liquid. An object of the present invention is to provide a pile filling liquid excellent in workability capable of blending with a low viscosity with a large water / binder ratio.

The pile circumference filling liquid according to claim 1 of the present application is a pile circumference filling liquid obtained by adding water to a binder mainly composed of cement, wherein the cement is blast furnace cement type B, and the binder is based on its weight. Anhydrous gypsum as an industrial by-product is contained in an amount of 7 to 9% by weight , and the water / binder ratio is 80 to 100%.

Moreover, the pile circumference filling liquid according to claim 2 of the present application is a pile circumference filling liquid obtained by adding water to a binder mainly composed of cement, wherein the cement is ordinary Portland cement, and the binder is added to its weight. On the other hand, it is characterized in that it contains 6% by weight or more and 8% by weight or less of anhydrous gypsum as an industrial by-product , and the water / binder ratio is 80 to 100%.

  As a material that gives expansion performance, there is a material that generates ettringite by reacting with cement, and an inexpensive gypsum generated in the process of generating hydrofluoric acid is a material that is low in cost. In addition, there are dihydrate gypsum produced as a countermeasure for desulfurization of factory flue gas, and dihydrate gypsum produced when fertilizer produces phosphoric acid.

  Although these are all industrial by-products, the present invention has been subjected to various experiments and studies using these inexpensive materials. Is obtained, and the compounding of the pile periphery filling liquid which was excellent also in workability was discovered.

  That is, when blast furnace cement type B is used as the main cement of the binder, 7% by weight or more of anhydrous gypsum is contained with respect to the total weight of the binder, and the water / binder ratio is 80 to 100%. (Claim 1), various performances aimed by the present invention can be obtained.

  When the anhydrous gypsum is less than 7% by weight, as can be seen from the test results described later, sufficient expansion performance and frictional resistance as a pile circumference filling liquid cannot be obtained. When anhydrous gypsum is included in an amount of more than 8% by weight, even if the expansion performance is increased, the frictional resistance is not improved so much. It is considered appropriate.

  In addition, the water / binder ratio was set to 80-100% by increasing the blending ratio of water so that the water / binder ratio was 80% or more. This is because it is easy to obtain fluidity, and when it exceeds 100%, it is difficult to ensure the required strength.

  In the present application, the water / binder ratio means the ratio between the weight of water and the total weight of the binder including cement and anhydrous gypsum or dihydrate gypsum.

  Claim 2 is a case where ordinary Portland cement is used instead of the blast furnace cement type B in Claim 1, and as can be seen from the test results described later, when ordinary Portland cement is used, anhydrous gypsum is added to the entire binder. When the content is 6% by weight or more with respect to the weight and the water / binder ratio is 80 to 100%, various performances aimed by the present invention can be obtained.

  Further, for the same reason as in the case of claim 1, it is considered that the anhydrous gypsum is about 8% by weight or less.

The pile circumference filling liquid according to claim 3 of the present application is a pile circumference filling liquid formed by adding water to a cement-based binder, wherein the cement is blast furnace cement type B, and the binder is based on its weight. It is characterized by containing dihydrate gypsum as an industrial by-product in an amount of 9% by weight to 12% by weight and a water / binder ratio of 80 to 100%.

  Claim 3 is a case where dihydrate gypsum is used instead of anhydrous gypsum in claim 1, and as can be seen from the test results described later, when dihydrate gypsum is used, it is 9% by weight or more based on the total weight of the binder. If it is contained and the water / binder ratio is 80 to 100%, various performances aimed by the present invention can be obtained.

  For the same reason as in the case of claim 1, it is considered that about 12% by weight of dihydrate gypsum is appropriate.

The pile circumference filling liquid according to claim 4 of the present application is a pile circumference filling liquid in which water is added to a binder mainly composed of cement, and the cement is ordinary Portland cement, and the binder is an industry for its weight. Dihydrate gypsum as a by-product is contained in an amount of 8% by weight or more and 10% by weight or less , and the water / binder ratio is 80 to 100%.

  Claim 4 is a case where ordinary Portland cement is used instead of the blast furnace cement type B in Claim 3, and as can be seen from the test results described later, when ordinary Portland cement and dihydrate gypsum are used, dihydrate gypsum. If the amount of water is 8% by weight or more based on the total weight of the binder and the water / binder ratio is 80 to 100%, various performances aimed by the present invention can be obtained.

  For the same reason as in the case of claim 1, it is considered that dihydrate gypsum is suitable within about 10% by weight.

  According to the present invention, a predetermined amount of a binder mainly composed of cement is replaced with a material that is inexpensively available as an industrial by-product such as anhydrous gypsum or dihydrate gypsum, so that an expensive expansion material, particularly an admixture, etc. Even if it is not used, the strength required as the pile circumference filling liquid can be ensured and the water / binding material ratio is set to 80 to 100%, so that a low viscosity workable pile circumference filling liquid can be obtained. .

  FIG. 1 relates to the invention according to claim 1 and shows the test results for determining the relationship between the anhydrous gypsum replacement rate and the expansion strain.

  That is, blast furnace cement type B is used as the main cement of the binder, the weight of anhydrous gypsum relative to the total weight of the binder is defined as the substitution rate, and the expansion strain is measured for various substitution rates. The graph shows the relationship between age and expansion strain for%, 6%, 7%, 8%, and 9%. The water / binder ratio (W / B) was 85%.

  In this test, a pile circumference filling liquid was placed in a 30 cm × 10 cm × 10 cm polypropylene mold with an embedded gauge installed in the center, and the mold was removed the next day. It was cured so as not to dry, and the amount of expansion was measured under a curing condition of 20 ° C.

  FIG. 2 relates to the invention according to claim 1 and shows the test results for the relationship between the anhydrous gypsum replacement rate and the punching resistance.

  In this test, a steel pipe having an outer diameter of 139.8 mm and a height of 160 mm is filled with a pile circumference filling liquid, and a circular plate having the same diameter as the inner diameter of the steel pipe is loaded at a predetermined age (7 days, 14 days). The maximum load value at the time of punching was measured by installing it on the surface and pressing it with a compression tester.

  As can be seen from FIGS. 1 and 2, when the punching resistance due to the expansion of the filling liquid filled in the steel pipe is measured, the values are almost the same at the substitution rates of 7% and 9%, and the expansion amount is 1200 μm or more as a guide. If there is, there is not much difference in punching resistance.

  However, if more gypsum is added, the strength is decreased and the cost is increased. Therefore, a substitution rate of 7% is a preferable mixing ratio in terms of performance and cost.

  In FIG. 1, when the replacement ratios are 5% and 6%, the expansion strain does not reach 1000 μm, which is not sufficient for the strength and friction required as the pile circumference filling liquid.

  FIG. 3 relates to the invention according to claim 2 and shows the test results for determining the relationship between the anhydrous gypsum replacement rate and the expansion strain.

  FIG. 4 shows the test results for determining the relationship between the dihydrate gypsum replacement rate and the expansion strain in the same manner as in the invention according to claim 3.

  FIG. 5 relates to the invention according to claim 4 and shows the test results for determining the relationship between the dihydric gypsum replacement rate and the expansion strain.

  As shown in FIGS. 3 to 5, the present inventor found that a preferable mixing ratio for obtaining an expansion amount of 1200 μm or more in each combination is 6% for a combination of ordinary Portland cement and anhydrous gypsum (Claim 2), and a blast furnace. It was found that the combination of Cement B type and dihydrate gypsum (Claim 3) was 9%, and the combination of ordinary Portland cement and dihydrate gypsum (Claim 4) was 8%.

  Table 1 summarizes typical blending examples of the pile periphery filling liquid of the present invention.

It is a graph which shows the test result which calculated | required the relationship between the anhydrous gypsum substitution rate and the expansion distortion regarding the invention which concerns on Claim 1. It is a graph which shows the test result which calculated | required the relationship of the anhydrous gypsum substitution rate and the punching resistance regarding the invention which concerns on Claim 1. It is a graph which shows the test result which calculated | required the relationship between the anhydrous gypsum substitution rate and the expansion distortion regarding the invention which concerns on Claim 2. It is a graph which shows the test result which calculated | required the relationship of the dihydric gypsum substitution rate and the expansion distortion regarding the invention which concerns on Claim 3. It is a graph which shows the test result which calculated | required the relationship of the dihydric gypsum substitution rate and the expansion distortion regarding the invention which concerns on Claim 4.

Claims (4)

In the pile circumference filling liquid in which water is added to a binder mainly composed of cement, the cement is blast furnace cement B, and the binder is 7 wt% or more and 9 wt % of anhydrous gypsum as an industrial by-product with respect to its weight. The pile circumference filling liquid is characterized in that it is contained within the range of 80% and the water / binder ratio is 80 to 100%. In the pile circumference filling liquid in which water is added to a binder mainly composed of cement, the cement is ordinary Portland cement, and the binder is 6% by weight to 8% by weight of anhydrous gypsum as an industrial by-product with respect to its weight. The pile circumference filling liquid is characterized in that it is contained within and the water / binder ratio is 80 to 100%. In pile circumferential packing solution comprising adding water to the binder mainly composed of cement, the cement is a blast furnace slag cement B species, the binding material is the weight to the gypsum as industrial byproduct 9 wt% or more 12 A pile circumference filling liquid containing within weight% and having a water / binder ratio of 80 to 100%. In a pile circumference filling liquid in which water is added to a binder mainly composed of cement, the cement is ordinary Portland cement, and the binder is dihydrate gypsum as an industrial by-product with respect to the weight of 10 wt % or more. The pile circumference filling liquid is characterized in that it is contained within the range of 80% and the water / binder ratio is 80 to 100%.

Images