JP6252008B2 - Seawater kneaded mortar used in pre-packed concrete methods and post-packed concrete methods, and methods for producing cold concrete using these methods - Google Patents

Description

  The present invention relates to a seawater kneaded mortar used in a prepacked concrete method or a postpacked concrete method. Moreover, it is related with the manufacturing method of the cold concrete using these construction methods.

  A large amount of concrete debris is generated by the Great East Japan Earthquake, and its effective use is urgently needed. In addition, harbor facilities have been severely damaged by the tsunami, and in the future, a large amount of concrete will be required to restore the facilities, but there is a concern that there will be a shortage of concrete aggregate.

  Under such circumstances, if concrete debris is crushed to produce concrete debris and the concrete debris can be used as coarse aggregate, the concrete debris can be effectively used and the shortage of aggregate for concrete can be suppressed.

  It is conceivable to use the prepacked concrete method described in Patent Document 1 when using concrete waste. This pre-packed concrete method is a method of manufacturing a new concrete product by containing concrete debris in a formwork and injecting and curing mortar or concrete into the voids of the concrete debris.

  It is also conceivable to use a post-packed concrete method similar to the pre-packed concrete method. This post-packed concrete method is a method of manufacturing a new concrete product by containing concrete scraps in a formwork infused with mortar or concrete and curing it.

JP 2004-203633 A

  Here, the concrete produced from concrete debris varies in quality such as strength. For this reason, when manufacturing a new concrete product, sufficient strength must be ensured even when using a concrete scrap having a relatively low strength.

  Moreover, when using concrete waste, there is a demand to use as much concrete waste as possible. This is because if large concrete waste can be used, it is possible to reduce the time and effort of crushing and increase the production efficiency of new concrete products. However, when large concrete waste is used, the concrete residue and mortar are easily separated from each other due to bleeding that occurs during curing. Bleeding can also cause sand bars on the surface of new concrete products. In addition, this bleeding occurs remarkably in a cold environment.

  Furthermore, early mold release of the mold is desirable when manufacturing new concrete products. This is because if the period until demolding is shortened, the frequency of use of the mold that is repeatedly used increases, and the mold can be used efficiently. In particular, in a cold environment, the period until demolding tends to be long. For this reason, there is a great demand for early demolding.

  This invention is made | formed in view of such a situation, The main objective is to ensure the intensity | strength required in a new concrete product, even if it uses the big concrete waste which has dispersion | variation in quality. Another object is to suppress bleeding by increasing the production efficiency by early demolding of the mold, particularly in a cold environment.

In order to achieve the above-mentioned object, the present invention is an injection mortar used in a prepacked concrete construction method or a postpacked concrete construction method using a concrete aggregate crushed into a size of 200 mm or more and 500 mm or less as a coarse aggregate. there are, and one or both of blast furnace slag cement B species and fly ash cement B-type, and lime expanding material comprising a binder, a mixing water seawater mixing kneaded and fine aggregate, the aluminum powder blowing agent Is added .

  According to the present invention, since the concrete waste crushed to a size of 200 mm or more and 500 mm or less is used, the labor of crushing can be reduced and workability is improved. When the minimum size of concrete is 200 mm or more, the amount of coarse aggregate is reduced compared to general pre-packed concrete and the strength burden on the mortar part is increased, but the mixing water for mixing the binder and fine aggregate is mixed. As seawater is used, the strength of the mortar can be increased as compared with the case where fresh water is used. Thereby, strength required for a new concrete product can be secured.

In addition, since the initial strength can be improved as compared with the case where fresh water is used as the kneading water, the period until demolding can be shortened, the production efficiency can be increased, and the bleeding can be suppressed.
Furthermore, since a blowing agent of aluminum powder was added and blast furnace cement type B or fly ash cement type B and an expanding material were used as the binder, adhesion between the mortar and the concrete residue was caused by the action of the expanding agent and the expanding material. And the integrity of new concrete products can be increased. Also, the mortar can be filled on the surface of the mold without gaps. Furthermore, higher strength is obtained than when ordinary Portland cement is used.

  In the above-mentioned mortar for injection, when the P funnel flow-down time is 20 seconds or more and 90 seconds or less, the minimum size of the concrete is large, so that the mortar can be used by kneading, which contributes to suppression of bleeding. .

  In the mortar for pouring described above, when the water binder ratio of the seawater and the binder is 40% or less, the strength in a new concrete product can be increased and bleeding can be suppressed.

In addition, the method for producing cold concrete according to the present invention includes a coarse aggregate made of concrete crushed to a size of 200 mm or more and 500 mm or less , one or both of blast furnace cement B type and fly ash cement B type, and lime-based A binder and a fine aggregate made of an expansion material are kneaded with seawater, and an injection mortar to which an aluminum powder foaming agent is added and the coarse aggregate are accommodated, and the injection mortar is injected. And using the mold, injecting the injection mortar into the mold containing the coarse aggregate, or storing the coarse aggregate in the mold into which the injection mortar is injected, and the injection The mold is removed on the condition that the period of initial strength has elapsed since the injection of the mortar for use.

  According to the present invention, concrete waste generated in large quantities in the earthquake can be effectively utilized without being crushed as much as possible. And even if it uses a big concrete bar with a dispersion | variation in quality, the intensity | strength required in a new concrete product can be ensured. Furthermore, bleeding can be suppressed even in a cold environment, and production efficiency can be increased.

It is a figure explaining the material of the mortar used for the test of a mixing | blending examination. It is a figure explaining concrete waste. It is a figure explaining the target performance and basic composition of mortar. It is a graph which shows the relationship between P funnel flow time and a fine aggregate binder ratio (S / B). It is a graph which shows the relationship between air quantity and a fine aggregate binder ratio (S / B). It is a graph which shows the relationship between an expansion coefficient and aluminum powder addition amount. It is a figure explaining the mixing | blending etc. which were determined. It is a graph which shows the result of a compressive strength test. It is a figure which shows the example of application of the concrete product in a breakwater restoration construction. It is a figure explaining the concrete product of manufacture object. It is a figure explaining the material of the mortar used for manufacture of a concrete product. It is a figure explaining the mixing | blending of mortar and concrete. It is a figure explaining the construction flow of the wave-dissipating block by a prepacked concrete construction method. It is a figure explaining the construction flow of the consolidation block by a post-packed concrete construction method. It is a photograph explaining the construction flow of the caisson model by the recycled aggregate concrete. It is a photograph of a core specimen taken from pre-packed concrete. It is a figure explaining the result of a compressive strength test. It is a graph which shows the initial strength change of each concrete heat-cured at the temperature of about 5 degreeC. It is a graph which shows the initial stage strength change of each concrete cured at different room temperature.

  In order to make effective use of concrete debris, the inventors of the present invention produce concrete debris by crushing concrete debris and manufacture concrete products by pre-packed concrete method and post-packed concrete method using this as coarse aggregate. Inspired. At that time, as the mortar for injection, a mixture and a fine aggregate kneaded with seawater were used. This is because the initial strength and long-term strength of the concrete product are improved by using seawater as the mortar mixing water.

  In order to realize this manufacturing method, the composition of mortar for injection was first examined, and then test construction using a pre-packed concrete method or a post-packed concrete method was performed. Hereinafter, these contents will be described.

  As shown in FIG. 1, the mortar for injection was prepared using water (W) for mixing, a binder (B), a fine aggregate (S), and a foaming agent (Al).

Two types of water were prepared: fresh water and seawater. Tap water was used as fresh water, and seawater having a chloride ion concentration of 1.88% was used. As the binder, cement (S) and an expansion material (Ex) were used. As the cement, a blast furnace cement type B having a density of 3.04 g / cm ³ was used, and as the expansion material, a lime-based expansion material having a density of 3.16 g / cm ³ was used. As the fine aggregate, crushed sand having a density of 2.66 g / cm ³ and a size of 5 mm or less was used. Aluminum powder was used as the foaming agent.

As shown in FIG. 2 (a), the concrete aggregate as the coarse aggregate was produced by crushing the concrete debris generated by the earthquake and selecting one having a predetermined size range. In this examination, as shown in FIG.2 (b), the thing with a dimension of 200-400 mm was selected. In addition, the dimension here means the dimension of the largest part in each concrete waste. The density of the selected concrete debris was 2.37 g / cm ³ , the water absorption was 7.18%, and the compressive strength was 37.2 N / mm ² .

  FIG. 3A shows the target performance of the mortar. As shown in the figure, P funnel flow time, air amount, bleeding rate, and expansion rate were used as indices.

  The P funnel flow-down time was measured by a fluidity test method for mortar for pouring pre-packed concrete defined in JSCE F 521, Japan Society of Civil Engineers. With regard to the P funnel flow time, the standard value of the P funnel flow time is set to 16 to 20 seconds in the pre-packed concrete specified in the concrete standard specification [construction]. However, the concrete used in this study has a size of 200 to 400 mm, which is larger than the coarse aggregate for prepacked concrete that is usually used. Therefore, the idea of using the mortar by kneading was conceived, and the target value of the P funnel flow-down time was set to 20 to 40 seconds to try to ensure the fillability.

  The amount of air was measured by a test method based on the pressure of the amount of air in fresh concrete specified in JIS A 1128. Assuming that the concrete product is subjected to freeze-thaw action in a cold environment, 8.0 to 12.0% was set as a target value for this air amount.

  The bleeding rate and the expansion rate were measured by the method of testing the bleeding rate and the expansion rate of the mortar for prepacked concrete specified in JSCE F 522 of the Japan Society of Civil Engineers. Regarding the bleeding rate, the target value was set to 3% or less in 3 hours. Moreover, regarding the expansion coefficient, 2 to 5% was set as a target value.

FIG. 3 (b) shows a basic composition of mortar using seawater. This mortar, the unit amount of seawater 357 kg / ^{m 3,} blast furnace cement type B unit amount of 703kg / ^{m 3,} defining the unit quantity of fine aggregate to 844kg / ^{m 3.} And the water binder ratio (W / B) of a binder and seawater was set to 50%, and the fine aggregate binder ratio (S / B) was set to 1.2. With respect to this basic composition, the foaming agent (aluminum powder) and the expanding material described in FIG. 1 were used for the purpose of ensuring the integrity of the mortar and concrete and suppressing cracking due to shrinkage.

Based on the basic composition, the seawater binder ratio and fine aggregate binder ratio were changed, and the amount of foaming agent added was changed for testing. Specifically, the water binder ratio is set to 50% and 45%, the fine aggregate binder ratio is set in the range of 1.0 to 2.0, and the addition amount of the foaming agent is 20, 40, 60 g / determined to m ^3.

  FIG. 4 shows the relationship between the P funnel flow time and the fine aggregate binder ratio. As shown in the figure, the P funnel flow time at a fine aggregate binder ratio of 1.0 was 20 seconds, and the P funnel flow time at a binder ratio of 1.7 was 40 seconds. For this reason, it was confirmed that the fine funnel binder ratio was set to 1.0 or more and 1.7 or less, so that the P funnel flow time could be kept within the target range (20 to 40 seconds). In this range, since mortar can be used by kneading, bleeding can be suppressed.

  FIG. 5 shows the relationship between the amount of air and the fine aggregate binder ratio. As shown in the figure, the air amount at the fine aggregate binder ratio of 1.17 was 8%, and the air amount at the binder ratio of 2.0 was 12%. For this reason, it has been confirmed that the air amount can be within the target range (8 to 12%) by setting the fine aggregate binder ratio to 1.17 or more and 2.0 or less.

FIG. 6 shows the relationship between the expansion rate and the amount of aluminum powder added. As shown in the figure, when 20 g / m ³ of aluminum powder was added, the expansion coefficient was 1%, and when 60 g / m ³ of aluminum powder was added, the expansion coefficient was slightly higher than 6%. From these results, it was considered that when 30 g / m ³ of aluminum powder was added, the expansion rate was 2%, and when 50 g / m ³ of aluminum powder was added, the expansion rate was 5%. Then, by determining the amount of aluminum powder to 30 g / ^{m 3} or more 50 g / ^{m 3} or less was considered to be videos expansion within the target range (2-5%). Moreover, when seawater was used as the kneaded water, it was also confirmed that the expansion rate tends to be higher than when fresh water was used.

FIG. 7 shows the blending of mortar determined based on these results. In this blending, 40 kg / m ³ of the expansion material was replaced with blast furnace type B cement with respect to the mortar with reference to the standard usage. Moreover, in order to satisfy the target value of the expansion coefficient, the amount of aluminum powder added was set to 40 g / m ³ .

  Using the determined mortar, a concrete block having a side of 800 mm was prepared by a prepacked concrete method. In addition, regarding the mixed water, two types of seawater and fresh water were used, and concrete blocks were prepared for each. Then, at a material age of 7 days, a core specimen of φ150 mm × 800 mm was sampled. A sample of only mortar was also prepared. This sample had a columnar shape with a diameter of 50 mm and a length of 100 mm, and was subjected to measurement at a material age of 28 days.

FIG. 8 shows the result of the compressive strength test. Compressive strength of mortar by mixing kneading in seawater increased from 24N / mm ² when kneaded with fresh water to 35N / mm ² to about 1.5 times. Moreover, the compressive strength of the prepacked concrete using seawater also increased to about 1.5 times the compressive strength of the prepacked concrete using fresh water, and became 27 N / mm ² .

  The prepared pre-packed concrete was filled with mortar to every corner of the mold, both using seawater and using fresh water. Further, it was confirmed that no gap was generated at the interface between the mortar and the concrete waste in the sampled core. As described above, the reason why the mortar is densely packed is that a foaming agent of aluminum powder is added and that the blast furnace cement B type and the expansion material are used as the binder.

  As shown in FIG. 7, the P funnel flow time of this mortar was 22.0 seconds. From this, when the minimum dimension of concrete waste was 200 mm, it was confirmed that the fillability could be ensured by adjusting the P funnel flow time of mortar to 22.0 seconds. In addition, the bleeding rate was 2.4%, and the target value of 3% or less was achieved.

In addition, in the prepacked concrete produced this time, the volume ratio of the concrete residue in the block was 50 to 53%. From this, it was confirmed that 0.5 m ³ of concrete waste can be processed per 1 m ^{3 of} the concrete product.

  Next, a description will be given of an application example of a concrete product made of concrete waste as coarse aggregate in breakwater restoration work. As shown in FIG. 9, three types of concrete products, a wave-dissipating block 1, a root-blocking block 2, and a caisson 3 model (caisson model), were actually produced and tested.

As shown in FIG. 10, the wave-dissipating block 1 is a tetrapot 25t type, and the design reference strength is set to 18 N / mm ² . There were two placement methods: a prepacked concrete method and a normal method (concrete). As the coarse aggregate, 300 to 500 mm of concrete waste (300 mm waste) was used in the prepacked concrete method, and 25 mm of normal aggregate was used in the normal method. Concrete debris used was crushed debris from existing caisson damaged. Regarding kneading water, two types of fresh water and seawater were used in the prepacked concrete method, and seawater was used in the normal method.

The root hardening block 2 has a relatively flat rectangular parallelepiped shape (L4.0 m × B3.0 m × H1.5 m), and the design standard strength is set to 18 N / mm ² . There were two placement methods: a post-packed concrete method and a normal method (concrete). As the coarse aggregate, a 300-500 mm concrete scrap was used in the post-packed concrete method, and a 25 mm normal aggregate was used in the normal method. As the kneading water, two kinds of fresh water and seawater were used in the post-packed concrete method, and seawater was used in the normal method.

The model of the caisson 3 is a block body (L2.5 m × B2.0 m × H2.5 m) having an L shape in a side view, and the design standard strength is set to 24 N / mm ² . The placement method was only the normal construction method (concrete). As the coarse aggregate, 40 mm concrete and 25 mm ordinary aggregate were used. For the mixing water, two kinds of fresh water and seawater were used for concrete, and seawater was used for ordinary aggregate.

  FIG. 11 shows the materials used, and FIG. 12 shows the formulation. Regarding the materials used, the water W used for mixing was seawater collected on site and tap water. As the cement C, blast furnace cement B type was used. As the expansion material Ex, a lime-based expansion material was used. Silica fume SF was used as an admixture. The fine aggregate S used crushed sand, and the coarse aggregate G for concrete used crushed stone. Special aluminum powder was used as the foaming agent AL. In addition, the high performance AE water reducing agent SP was added to the mortar for injection, and the special admixture AN and the AE water reducing agent WR were added to the concrete.

Regarding the blending, in the mortar for injection used in the pre-packed concrete method and the post-packed concrete method, the water binder ratio W / B was set to 40.0% and the fine aggregate binder ratio S / B was set to 1.7. The reason why W / B is set to 40.0% is to increase the strength of the manufactured concrete product and suppress bleeding. Then, the unit quantity of water W 263 kg / ^{m 3,} the unit amount of cement C 618kg / ^{m 3,} the expansion member unit amount of 40 kg / ^{m 3} of Ex, fine aggregate unit amount of 1119kg / ^{m 3} S and, The unit amount of the blowing agent AL was set to 0.04 kg / m ³ (40 g / m ³ ). Moreover, about the high performance AE water reducing agent SP and AE water reducing agent WR, the amount was adjusted and added so that desired water binder ratio W / B and unit water amount might be obtained.

  The target performance of the injection mortar is as described in FIG. 3A, but the target value of the P funnel flow time was extended to about 90 seconds. That is, it was set to 20 to 90 seconds. This is because the coarse aggregate size is as large as 300 to 500 mm and the gap to be injected is large.

Moreover, in the concrete used for the normal construction method, the water binder ratio W / B was set to 64.6%, and the fine aggregate ratio s / a was set to 48.8%. Then, the unit quantity of water W 172kg / ^{m 3,} the unit amount of cement C 241kg / ^{m 3,} the unit amount of 25 kg / ^{m 3} admixtures, 886Kg the unit quantity of fine aggregate S / ^{m 3,} coarse aggregate The unit amount of the material G was set to 944 kg / m ³ , and the unit amount of the special admixture AN was set to 13 kg / m ³ .

  In FIG. 13, the construction flow of the wave-dissipating block 1 by a prepacked concrete construction method is shown. As shown in the figure, in this construction method, concrete scrap 12 is first put into the mold 11 by a backhoe BH or the like. Then, while attaching the upper end part of the formwork 11, the injection pipe 13 of mortar is set. Further, the concrete scraper 12 is put into the upper end of the formwork by human power. When the concrete litter 12 is put into the entire mold 11, the pouring mortar 14 is poured from the bottom of the mold. When the injection mortar 14 is injected up to the upper end of the mold 11, the injection pipe 13 is removed to finish the top end. Then, when the predetermined period has elapsed and the necessary initial strength has been developed, the mold 11 is removed.

  In FIG. 14, the construction flow of the consolidation block 2 by a post-packed concrete construction method is shown. As shown in the figure, in this construction method, first, an injection mortar 22 having an amount slightly smaller than the required amount is placed inside the mold 21. Thereafter, concrete scrap 23 is put into the mold 22 by the backhoe BH or the like. If the concrete waste 23 is thrown in, the pouring mortar 22 will be driven to the upper end of the formwork 21, and the top end will be finished. Then, when a predetermined period has elapsed and a necessary initial strength has been developed, the mold 21 is removed.

  In FIG. 15, the construction flow about the model 33 of the caisson 3 by a normal construction method is shown. As shown in the figure, in the normal construction method, first, the epoxy coating rebar 31 is assembled into an L-shaped block shape. When the reinforcing bar 31 is assembled, the mold frame 32 is assembled so as to surround the reinforcing bar 31. After the formwork 32 is assembled, concrete is placed in the formwork. When concrete is poured to the top of the formwork, finish the top edge. Then, when a predetermined period has elapsed and a necessary initial strength has been developed, the mold 32 is removed, and a model 33 of the caisson 3 is obtained.

  Next, quality evaluation regarding the produced concrete product will be described. Quality was evaluated by compressive strength. Regarding the specimen for measuring the compressive strength, for the wave-dissipating block 1 and the rooting block 2, a core specimen of φ150 mm × 300 mm molded from a block having a side of 800 mm is used, and for the model 33 of the caisson 3, φ100 mm × 200 mm A specimen was created.

  FIG. 16 shows an overall photograph and a partially enlarged photograph of a core specimen (φ150 mm × 800 mm) collected from prepacked concrete. As shown in this photograph, it was confirmed that no gap was generated at the interface between the mortar and the concrete residue.

As shown in FIG. 17, regarding the model 33 of the wave-dissipating block 1, the root-setting block 2, and the caisson 3, the design reference strength (wave-dissipating block) can be used for any sample using fresh water and seawater as mixing water 1 and 18N / mm ² at the root compaction block 2, it was confirmed that satisfies 24N / mm ²⁾ in a model 33 of the caisson 3. In particular, for the sample using seawater, the design standard strength was satisfied at a material age of 7 days. From this, it was confirmed that when seawater was used as the mortar mixing water, the onset of initial strength was accelerated. Moreover, since blast furnace cement type B is used, it is considered that higher strength was obtained than when ordinary Portland cement was used.

  FIG. 18 is a graph showing changes in initial strength of each concrete heat-cured at an air temperature of about 5 ° C. In this graph, pre-packed concrete uses seawater as mortar mixing water. Post-packed concrete uses fresh water as mortar mixing water. And the compressive strength of the material age 1st, 3rd, 7th is measured and plotted.

As shown in the figure, in pre-packed concrete using seawater, 5 N / mm ^2, which is a strength necessary for demolding at a material age of 1 day (demolding strength), is expressed. On the other hand, post-packed concrete using fresh water takes 3 days until 5 N / mm ² is expressed. From this, it can be understood that by using seawater as mortar mixing water, the initial strength is excellent even in a cold environment, and demolding can be performed earlier than when using fresh water. Thereby, manufacturing efficiency can be improved and it contributes also to bleeding suppression.

  In order to confirm the superiority of the initial strength development by seawater, laboratory experiments were conducted. In this laboratory experiment, three types of concrete were compared. The first type is concrete using seawater, the second type is concrete using fresh water, and the third type is seawater kneaded with fly ash and special additives using seawater, crushed sand and sea sand. It is concrete. In addition, the blast furnace cement B type was used as the cement for any concrete. Then, these concretes were cured under an environment at room temperature of 5 ° C. and an environment at room temperature of 20 ° C., and the compressive strength was measured at each of the ages 1 day, 3 days, and 7 days.

As shown in FIG. 19 (a), in an environment of room temperature of 5 ° C., the concrete (seawater-kneaded concrete) kneaded with seawater has a demolding strength of 5N. / Mm ² higher. On the other hand, the concrete kneaded with fresh water was slightly higher than the demolding strength of 5 N / mm ² at 7 days of age.

As shown in FIG. 19 (b), in an environment of room temperature of 20 ° C., all the concrete kneaded with seawater has a compressive strength of 1 day of age than 5 N / mm ² which is a demolding strength. It became high. On the other hand, the concrete kneaded with fresh water exceeded the demolding strength of 5 N / mm ² at the age of 3 days.

  From the above experimental results, it was confirmed that by using seawater as the mixing water, the initial strength was developed earlier than when fresh water was used regardless of the room temperature, and demolding could be performed early. The reason is that the binder reacted early due to the salt contained in the seawater.

  Also, regarding the curing period until demolding, it took 1 day for concrete using seawater and 2 days for concrete using fresh water in an environment at room temperature of 20 ° C. It took 3 days for the concrete using 6 and 6 days for the concrete using fresh water. From this, it was confirmed that the curing period until demolding in a cold environment can be shortened by using seawater.

  The above results are summarized. This time, the concrete crushed to a size of 200mm or more and 500mm or less is used as coarse aggregate, and seawater is used as mixing water for mortar, and new concrete products (wave-dissipating block 1, rooting block 2) Was made. And it confirmed that the strength required as a concrete product was obtained.

  In this concrete product, since the concrete scrap of 200 mm or more is used as the coarse aggregate, it is possible to reduce the labor of crushing and improve workability. Moreover, since seawater is used as the kneading water, the strength of the mortar can be increased as compared with the case where fresh water is used. Thereby, strength required for a new concrete product can be secured.

  In addition, the binder reacts early due to the salt contained in the seawater. Thereby, initial strength can be improved rather than the case where fresh water is used as kneading water. Therefore, the period until demolding is shortened, and the production efficiency can be increased.

In addition, since a high-performance AE water reducing agent is added as a special admixture for the mortar for injection, while ensuring its fluidity (20 to 90 seconds, more preferably 20 to 40 seconds in P funnel flow time) The water binder ratio W / B can be 40% or less, and the unit water amount can be 270 kg / m ³ or less.

  The above description of the embodiment is for facilitating the understanding of the present invention, and does not limit the present invention. The present invention can be changed and improved without departing from the gist thereof, and the present invention includes equivalents thereof.

  For example, regarding the binding material, the above-described concrete product is configured by the blast furnace cement type B and the expansion material, but is not limited thereto. For example, fly ash cement B type may be used instead of blast furnace cement B type or together with blast furnace cement B type. As a result, a higher strength can be obtained than when ordinary Portland cement is used. Moreover, regarding the binding material, it may be composed only of cement, excluding the expansion material.

DESCRIPTION OF SYMBOLS 1 ... Wave-dissipating block, 2 ... Rooting block, 3 ... Caisson model, 11 ... Formwork, 12 ... Concrete, 13 ... Mortar injection pipe, 14 ... Injection mortar, 21 ... Formwork, 22 ... Injection mortar 23 ... Concrete, 31 ... Epoxy coated rebar, 32 ... Formwork, 33 ... Caisson model, BH ... Backhoe

Claims (4)

It is a mortar for injection used in a pre-packed concrete construction method using a coarse aggregate of concrete crushed to a size of 200 mm or more and 500 mm or less, or a post-packed concrete construction method,
And one or both of blast furnace slag cement B species and fly ash cement B-type, and lime expanding material comprising a binder, a Mixing water seawater mixing kneaded and fine aggregate,
A mortar for pouring characterized by adding a blowing agent of aluminum powder .   The mortar for injection according to claim 1, wherein the P funnel flow time is 20 seconds or more and 90 seconds or less.   The mortar for injection according to claim 1 or 2, wherein a ratio of water binding material between the seawater and the binding material is 40% or less. Coarse aggregate made of concrete crushed into a size of 200 mm or more and 500 mm or less,
A mortar for injection to which one or both of blast furnace cement type B and fly ash cement type B, a lime-based expanding material and a fine aggregate are mixed with seawater, and an aluminum powder blowing agent is added ,
With the coarse aggregate being housed and the mold in which the mortar for injection is injected,
Injecting the injection mortar into the mold containing the coarse aggregate, or containing the coarse aggregate in the mold filled with the injection mortar,
A method for producing cold concrete, characterized in that the formwork is removed on condition that the period of initial strength has elapsed since the injection of the mortar for injection.