Concrete treatment methods

Abstract

To establish a concrete treatment technique for suitably treating hydrated concrete without relying on the instinct and experiment of an operator so as to be reused without waste.SOLUTION: A concrete treatment method has: a sampling step for sampling unused concrete (a pts.wt.) from a storage part of the unused concrete (A pts.wt.); a water addition step for gradually adding and mixing cleaning water (b pts.wt.) in a prescribed range to prepare hydrated concrete; an inspection step for gradually adding and mixing a polymer flocculant in a prescribed range to prepare plural samples and to execute slump tests of the respective samples; a determination step, in which, with the confirmation of the addition amount (c pts.wt.) of the polymer flocculant in the sample(s) in which a slump value is 0 and gaps are confirmed in the surface, it is determined that granulation is executed; and a calculation step for calculating the input (B pts.wt.) of the cleaning water and the input (C pts.wt.) of the polymer flocculant based on the a pts.wt., the b pts.wt. and the c pts.wt.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a concrete treatment method for reusing water-treated concrete, which is unused concrete to which washing water has been added. [Background technology]

[0002] Ready-mix concrete (JIS standard products) used in construction and civil engineering works hardens over time, so ideally, it should be used completely. However, in actual construction sites, more ready-mix concrete is ordered than necessary to allow for some leeway, resulting in surplus concrete that is not used and is disposed of as industrial waste. Unused ready-mix concrete includes concrete left over from construction sites, known as "residual concrete," and concrete returned to manufacturers or distributors without being used at all, known as "returned concrete."

[0003] In order to make effective use of such discarded ready-mixed concrete, the applicant has developed a technology to reuse granulated concrete, obtained by adding a polymer flocculant to unused ready-mixed concrete and mixing it, as crushed stone that can be used as roadbed material for paved roads and parking lots (see, for example, Patent Documents 1 and 2).

[0004] The method for producing recycled material described in Patent Document 1 involves adding and mixing a powdered polymer flocculant having a specific particle size to unused fresh concrete, thereby granulating the fresh concrete through the flocculation action of the polymer flocculant.

[0005] The method for producing recycled material described in Patent Document 2 involves adding and mixing a liquid amphoteric polymer flocculant to unused fresh concrete, thereby granulating the fresh concrete through the flocculation action of the polymer flocculant. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Patent No. 7103608 [Patent Document 2] Japanese Patent Publication No. 2022-39907 [Overview of the project] [Problems that the invention aims to solve]

[0007] Incidentally, when discharging unused ready-mix concrete from a concrete container in order to reuse it, the container is cleaned at the same time, resulting in the mixing of cleaning water with the ready-mix concrete. This unused ready-mix concrete with added cleaning water is referred to as "hydrated concrete" in this specification. Hydrated concrete no longer meets JIS standards and its properties are not consistent, so it is generally considered difficult to handle. Therefore, in order to reuse hydrated concrete, modifications such as improving granulation properties or suppressing fluidity are necessary.

[0008] Patent documents 1 and 2 also describe the modification (granulation) of unused concrete by adding polymer flocculants. However, when polymer flocculants are added to water-hydrated concrete mixed with wash water, the concrete may not granulate properly, making it difficult to find the optimal conditions. Currently, the processing of water-hydrated concrete relies on the intuition and experience of the workers. Furthermore, if the amount of polymer flocculant added to the water-hydrated concrete is incorrect when reusing it, the processed concrete may not develop sufficient strength to withstand use as recycled material, ultimately forcing it to be discarded. In this case, a large amount of non-recyclable concrete waste is generated, posing a significant burden in terms of environmental impact, economic efficiency, and labor.

[0009] This invention was made in view of the above-mentioned problems, and its purpose is to establish a concrete processing technology that enables the proper processing of water-added concrete without relying on the intuition or experience of workers, and to allow for its efficient reuse. [Means for solving the problem]

[0010] The characteristic configuration of the concrete treatment method according to the present invention, which solves the above problems, is as follows: A concrete treatment method in which unused concrete has been treated with water-added concrete using a polymer flocculant, A sampling process in which a small amount of unused concrete (a parts by weight) is taken as a sample from a storage unit that contains unused concrete (A parts by weight), The process involves adding and mixing wash water (b parts by weight) to the collected unused concrete in stages within a predetermined range to prepare hydrated concrete, The inspection process involves adding and mixing a polymer flocculant (c parts by weight) to the aforementioned hydrated concrete in stages within a predetermined range to prepare multiple samples, filling each sample into a slump cone, and performing a slump test. In the inspection step, a determination step is made in which the amount of polymer flocculant added (c parts by weight) to a sample in which the slump value after the slump test is 0 and voids are observed on the surface is confirmed, thereby determining that the water-added concrete has been granulated. A calculation step to calculate the amount of washing water (B parts by weight) and the amount of polymer flocculant (C parts by weight) to be added to the container that contains the unused concrete (A parts by weight), based on the aforementioned a parts by weight, b parts by weight, and c parts by weight. The purpose is to include it.

[0011] According to the method for treating concrete of this configuration, when treating and reusing the hydrated concrete, a small amount of unused concrete (a parts by weight) is sampled as a sample from the unused concrete (A parts by weight) stored in the storage section, and washing water (b parts by weight) and a polymer flocculant (c parts by weight) are added and mixed step by step within a predetermined range to this sample to prepare a plurality of specimens with different conditions, and by performing a slump test on each specimen, the conditions under which the hydrated concrete is granulated can be found. Then, based on the conditions (a parts by weight, b parts by weight, and c parts by weight) determined to have granulated the hydrated concrete, the amount of washing water (B parts by weight) to be introduced into the storage section storing the unused concrete (A parts by weight) and the amount of polymer flocculant to be introduced (C parts by weight) are calculated, and it becomes possible to actually treat the returned concrete and the remaining concrete at a construction site or the like. Thus, according to the method for treating concrete of this configuration, the conditions under which the hydrated concrete is granulated can be grasped by the slump test performed in advance, so that the hydrated concrete can be appropriately treated and reused without waste, without relying on the intuition or experience of the operator.

[0012] In the method for treating concrete according to the present invention, It is preferable that the hydrated concrete prepared in the hydration step is set such that the water addition rate with respect to the unused concrete is less than 1 × 10⁻² v / v% and the cement ratio is less than 95%.

[0013] According to the method for treating concrete of this configuration, when preparing hydrated concrete by adding and mixing washing water to unused concrete, since the water addition rate and the cement ratio with respect to the unused concrete are appropriately set, it is possible to obtain hydrated concrete that is easy to handle. Further, for such hydrated concrete that is easy to handle, the range of the addition amount of the polymer flocculant for granulation can be set wide.

[0014] In the method for treating concrete according to the present invention, In the sampling step, the amount (a parts by weight) of unused concrete sampled as a sample is preferably 0.02% or more of the storage capacity (A parts by weight) of the unused concrete stored in the storage unit.

[0015] According to the concrete processing method of this configuration, since a necessary and sufficient amount of unused concrete for performing a slump test under a plurality of conditions can be collected, the conditions under which the hydrated concrete is granulated can be examined in more detail. In addition, since the amount of unused concrete sampled as a sample does not become excessive, the amount of waste (concrete used in the test) discarded after the slump test can be reduced.

[0016] In the concrete processing method according to the present invention, It is preferable to carry out an input step of inputting the calculated amount of washing water (B parts by weight) and the polymer flocculant (C parts by weight) into the storage unit within 24 hours after collecting the unused concrete (a parts by weight).

[0017] According to the concrete processing method of this configuration, the washing water and the polymer flocculant are added and mixed into the storage unit before the unused concrete stored in the storage unit hardens (within 24 hours after sample collection), and the concrete can be surely processed.

[0018] In the concrete processing method according to the present invention, The polymer flocculant preferably contains an anionic polymer flocculant.

[0019] According to the concrete processing method of this configuration, by using an anionic polymer flocculant as the polymer flocculant, the granulation of the hydrated concrete is further promoted. In addition, since the anionic polymer flocculant has no problems such as fish toxicity, the impact on the environment is less than that of the cationic polymer flocculant.

[0020] In the concrete processing method according to the present invention, The size of the slump cone used in the slump test is preferably 50 mm in inner diameter at the top, 100 mm in inner diameter at the bottom, and 150 mm in height, or 100 mm in inner diameter at the top, 200 mm in inner diameter at the bottom, and 300 mm in height.

[0021] According to this concrete treatment method, inspection can be performed using a mini-slump test or a slump test. The mini-slump test is effective when the water content (water content) of the water-added concrete is high and the sample is prone to crumbling. It also allows confirmation of the conditions under which water-added concrete can be granulated using a small amount of sample. The slump test is effective when a highly reliable test conforming to JIS standards is desired.

[0022] In the concrete treatment method according to the present invention, The aforementioned storage unit is preferably a drum mounted on an agitator truck, a mixer for ready-mixed concrete, a mixer for manufacturing ready-mixed concrete, a ready-mixed concrete bucket, or a ready-mixed concrete hopper.

[0023] This concrete processing method allows for the processing and reuse of surplus, unused ready-mixed concrete that may be generated at most construction sites where ready-mixed concrete is used, as well as at ready-mixed concrete manufacturing sites, without any waste. [Brief explanation of the drawing]

[0024] [Figure 1] Figure 1 is a flowchart illustrating the concrete treatment method of the present invention. [Figure 2] Figure 2 shows an example of the results of the minislump test, where (a) is an example of a sample judged as "○" and (b) is an example of a sample judged as "×". [Figure 3] Figure 3 is a judgment map created based on the granulation test results of hydrated concrete using a powdered anionic polymer flocculant composition. [Figure 4] Figure 4 is a judgment map created based on the granulation test results of hydrated concrete using a liquid anionic polymer flocculant composition. [Modes for carrying out the invention]

[0025] Embodiments of the concrete treatment method of the present invention will now be described. However, the present invention is not limited to the following description.

[0026] [Target of treatment and chemicals used] First, the present invention will describe the water-added concrete to be treated and the chemicals used in its treatment method.

[0027] <Hydrated concrete> In this invention, the water-treated concrete is obtained by adding wash water to unused ready-mix concrete. The ready-mix concrete corresponds to ready-mix concrete in accordance with JIS A 5308 and is manufactured by mixing cement, water, fine aggregate, coarse aggregate, and admixtures. Examples of cement include Portland cement (JIS R 5210), blast furnace cement (JIS R 5211), silica cement (JIS R 5212), fly ash cement (JIS R 5213), and eco-cement (JIS R 5214). Examples of fine aggregate include sand and crushed sand. Examples of coarse aggregate include gravel and crushed stone. Examples of admixtures include air-entraining agents, water-reducing agents, hardening accelerators, and fluidizers.

[0028] <Washing water> When unused ready-mixed concrete is discharged from the container that holds it, the container is cleaned at the same time, so the unused ready-mixed concrete becomes hydrated concrete mixed with the cleaning water. In this case, any fresh water can be used as the cleaning water, such as tap water, industrial water, deionized water, groundwater, well water, river water, or lake water. However, tap water or industrial water is preferred due to its availability and the stability of the quality of the prepared hydrated concrete.

[0029] <Polymer flocculant> A polymer flocculant is added to the hydrated concrete. Here, the polymer flocculant may be used alone (i.e., in a form where the polymer flocculant is 100%) or in a polymer flocculant composition containing other components (i.e., in a form where the polymer flocculant is not 100%). Hereafter, when "polymer flocculant" is used in this specification, unless otherwise specified, it will include both the meaning of "polymer flocculant" and "polymer flocculant composition". As for the type of polymer flocculant, any of anionic polymer flocculants, cationic polymer flocculants, amphoteric polymer flocculants, and nonionic polymer flocculants can be used, but anionic polymer flocculants are preferred due to their superior granulation properties for hydrated concrete (described later) and their low environmental impact. Furthermore, among amphoteric polymer flocculants, anion-rich amphoteric polymer flocculants, in which anionic groups outnumber cationic groups, can be used in the same way as anionic polymer flocculants.

[0030] Examples of anionic polymer flocculants include polycarboxylates or copolymers of polycarboxylates and acrylamide, polysulfonates or copolymers of polysulfonates and acrylamide, and derivatives thereof. Examples of polycarboxylic acids for forming polycarboxylates include acrylic acid, methacrylic acid, itaconic acid, and maleic acid. Examples of polysulfonic acids for forming polysulfonates include acrylamide 2-methylpropanesulfonic acid, vinylsulfonic acid, and styrenesulfonic acid.

[0031] Examples of cationic polymer flocculants include alkylaminoacrylate polymers or copolymers of alkylaminoacrylate polymers and acrylamide, alkylaminomethacrylate polymers or copolymers of alkylaminomethacrylate polymers and acrylamide, and derivatives thereof. Examples of alkylaminoacrylate polymers include dimethylaminoethyl acrylate, dimethylaminopropyl acrylamide, acryloyloxyethyltrimethylammonium chloride, acryloylaminopropyltrimethylammonium chloride, and acryloyl 2-hydroxypropyl lide. Examples of alkylaminomethacrylate polymers include dimethylaminoethyl methacrylate, dimethylaminopropyl methacrylamide, methacryloyloxyethyltrimethylammonium chloride, methacryloylaminopropyltrimethylammonium chloride, and methacryloyl 2-hydroxypropyl lide.

[0032] Examples of amphoteric polymer flocculants include random copolymers, alternating copolymers, block copolymers, and graft copolymers of anionic monomers (the constituent units of anionic polymer flocculants), cationic monomers (the constituent units of cationic polymer flocculants), and nonionic monomers (if necessary). From the viewpoint of stability, random copolymers or alternating copolymers are preferred. The polymerization ratio of anionic monomers to cationic monomers is 30-45 mol%, preferably 35-42 mol%, for anionic groups, 0.1-10.0 mol%, preferably 0.1-4.0 mol%, for cationic groups, with the remainder being nonionic groups. In amphoteric polymer flocculants, the anionic groups of anionic polymer flocculants and the cationic groups of cationic polymer flocculants exist in the same polymer structure, but unlike a mixture of anionic and cationic polymer flocculants, phase separation does not occur, thus enabling stable flocculation (granulation).

[0033] The molecular weight of the polymer flocculant is 1.0 × 10⁻⁶, expressed as the weight-average molecular weight (Mw). 7 ~2.5×10 7Preferably, 1.3 × 10 7 ~2.2×10 7 This is more preferable. If the molecular weight of the polymer flocculant is within the above range, the granulation of the hydrated concrete will be excellent, and the strength of the formed granules will also be excellent.

[0034] The particle size of the polymer flocculant is preferably 50 mesh pass (approximately 0.3 mm) or less. If the particle size of the polymer flocculant is 50 mesh pass or less, the dispersibility when added to hydrated concrete will be good, and the processing time can be shortened. In addition, the contact area between the cement contained in the hydrated concrete and the polymer flocculant will be increased, which can contribute to improving the granulation properties of the hydrated concrete. When using anionic polymer flocculants as polymer flocculants, anionic polymer flocculants (anionic polymer flocculant compositions) are generally sold in granular form, so the particle size may be larger than 50 mesh pass. In such cases, the particle size can be adjusted to 50 mesh pass or less by crushing the granular anionic polymer flocculant with a ball mill or the like and then sieving it as necessary.

[0035] <Other medications> In the concrete treatment method of the present invention, in addition to polymer flocculants, dispersants, pH adjusters, etc., may be used as needed. Dispersants are used to prevent the polymer flocculant from clumping when it is added to and mixed with hydrated concrete. Examples of dispersants include inorganic powder materials such as calcium carbonate, titanium dioxide, kaolin, clay, bentonite, and zeolite. pH adjusters are used to optimize the flocculation (granulation) when anionic polymer flocculants or amphoteric polymer flocculants are used as polymer flocculants. Examples of pH adjusters include alkali metal and / or alkaline earth metal carbonates, bicarbonates, hydroxides, oxides, and phosphates.

[0036] [Concrete treatment methods] Next, the concrete treatment method of the present invention will be described. Figure 1 is a flowchart illustrating the concrete treatment method of the present invention. The concrete treatment method of the present invention involves treating water-hydrated concrete, which is unused concrete to which washing water has been added, using a polymer flocculant, and includes the following steps: sampling, water addition, inspection, determination, and calculation. In addition, an input step can be added as needed. The following describes each step with reference to the flowchart in Figure 1.

[0037] <Step 1: Sampling Process> Ready-mix concrete is usually stored in a storage area. Examples of storage areas include drums mounted on agitator trucks, ready-mix concrete mixers, ready-mix concrete manufacturing mixers, ready-mix concrete buckets, and ready-mix concrete hoppers. Furthermore, storage areas are not limited to the artificial structures mentioned above. For example, in a configuration where a hole or trench is formed by excavating the ground and ready-mix concrete is discharged from an agitator truck or the like into that hole or trench and stored there, the hole or trench formed in the ground can be considered a storage area. Not all of the ready-mix concrete stored in a storage area is used; some remains as unused concrete. Therefore, when processing this unused ready-mix concrete, a small amount of unused concrete is taken as a sample from the storage area containing the unused concrete (S1; sampling process). Here, the weight of the unused concrete remaining in the storage area to be processed is A parts by weight, and the weight of the small amount of unused concrete taken as a sample is a parts by weight. The amount of unused concrete sampled (a parts by weight) should be equal to or greater than the capacity of the slump cone used in the slump test described later (1L, 6L). For example, it can be 0.02% or more of the total unused concrete volume (A parts by weight) contained in the container. To match the capacity of the slump cone (1L, 6L), if the specific gravity of the unused concrete is 2.27, the amount of unused concrete sampled (a parts by weight) will be 2.27 kg (for 1L) or 13.62 kg (for 6L). There is no particular upper limit on the amount of unused concrete sampled (a parts by weight), but for example, it can be 5% or less of the total unused concrete volume (A parts by weight) contained in the container.

[0038] <Step 2: Water Addition Process> Next, a small amount of unused concrete (a parts by weight) taken as a sample is gradually mixed with washing water (b parts by weight) within a predetermined range to prepare hydrated concrete (S2; hydration step). This takes into account that in actual cleaning work of the containment area, there will be some variation in the amount of washing water used by workers. The amount of washing water added (b parts by weight) can be set to several points, for example, increasing by approximately 13 to 15 g increments within the range of 0 to 115 g. Incidentally, it is preferable that the hydrated concrete prepared in this hydration step has a water content of less than 10 v / v% relative to the unused concrete, and the cement ratio (ratio of water to cement) is set to less than 95 mass%. By setting it this way, hydrated concrete that is easy to handle can be obtained. Furthermore, with such easy-to-handle hydrated concrete, the range of the amount of polymer flocculant added for granulation can be set to be wide.

[0039] <Step 3: Inspection Process> Next, multiple samples are prepared by gradually adding and mixing a polymer flocculant (c parts by weight) to the hydrated concrete within a predetermined range, and each sample is filled into a slump cone to perform a slump test (S3; inspection process). Filling the slump cone with the sample is done, for example, by introducing the sample into the opening of the slump cone in three separate batches, tamping the surface of the sample 25 times with a tamping rod each time, and finally leveling the surface so that it is flush with the opening of the slump cone, resulting in a densely filled state. When using a polymer flocculant composition, the amount of polymer flocculant added (c parts by weight) can be appropriately adjusted according to the polymer flocculant content in the polymer flocculant composition. For example, the amount of polymer flocculant composition added (c parts by weight) can be set to multiple points increasing by 0.1 g increments within the range of 0.0 to 2.0 g. Slump testing is generally performed using a slump tester (upper inner diameter 100 mm × lower inner diameter 200 mm × height 300 mm) as specified in the "Slump Test Method for Concrete" compliant with JIS A 1101:2020. However, it may also be performed using a smaller mini-slump tester (upper inner diameter 50 mm × lower inner diameter 100 mm × height 150 mm). Inspection using a mini-slump tester is effective when the water content (water addition rate) of the water-added concrete is high and the sample is prone to crumbling. It also allows for confirmation of the conditions under which water-added concrete can be granulated using a small amount of sample. In the examples described later, slump testing was also performed using a mini-slump tester.

[0040] <Step 4: Judgment Process> Next, for each sample, it is determined whether the slump value after the slump test is 0 or not (S4-1). Here, "slump value is 0" means that when the slump cone filled with the sample is placed on a flat plate and the slump cone is pulled upward, the top of the frustoconical sample does not substantially decrease. However, even if the internal stress of the frustoconical sample is diverted outward immediately after the slump cone is pulled upward, and the top momentarily decreases as a result, if the decrease in the top stops immediately, the slump value is determined to be 0. First, for the first sample, it is determined whether the slump value after the slump test is 0 or not. If it is not 0 (S4-1; No), it is determined that it has not been granulated (S4-3). If it is 0 (S4-1; Yes), it is further determined whether voids are observed on the surface (S4-2). Here, "voids are observed on the surface" means that multiple holes of approximately the same size as the fine aggregate are visible to the naked eye on the surface of the sample. Samples without visible voids on the surface (S4-2; No) are determined not to have been granulated (S4-3). Samples with visible voids on the surface (S4-2; Yes) are determined to have been granulated based on the amount of polymer flocculant added (c parts by weight) in the sample (S4-4). The above steps (S4-1 to S4-4) are repeated for all samples in which the amount of washing water and polymer flocculant added is changed stepwise within a predetermined range (S4-5). Once the determination of all samples is complete, the overall picture of the conditions under which hydrated concrete is granulated can be grasped (S4; determination step). At this time, for example, if a determination map is created by taking the amount of washing water added (water amount) in the column direction (horizontal) and the amount of polymer flocculant added in the row direction (vertical), and the determination results of all samples are entered into this determination map and mapped, it becomes easy to grasp the overall picture of the conditions under which hydrated concrete is granulated.

[0041] <Step 5: Calculation Process> Next, based on the weight of the sampled unused concrete (a parts by weight), the weight of the added washing water (b parts by weight), and the amount of polymer flocculant added to the sample determined to have granulated (c parts by weight), the amount of washing water (B parts by weight) and the amount of polymer flocculant (C parts by weight) to be added to the container for the unused concrete are calculated (S5; calculation step). Here, parts B and C are determined by the following formulas. B = b × A / a C = c × A / a This calculation process should ideally be performed on all samples determined to be granulated in the above determination process. However, in the determination map, it is sufficient to perform the calculation process only on granulated samples adjacent to samples determined to be non-granulated.

[0042] <Step 6: Input Process> The washing water (B parts by weight) and polymer flocculant (C parts by weight) calculated in the above calculation process are added to the container holding the unused concrete as needed (S6; adding step). Here, it is preferable that the adding step be carried out within 24 hours of taking the unused concrete (a parts by weight). In this case, the concrete can be reliably treated before the unused concrete contained in the container hardens (within 24 hours of sample collection). [Examples]

[0043] As an example, a granulation test of hydrated concrete performed based on the concrete treatment method of the present invention will be described. The materials, test equipment, and test method used in this granulation test are shown below.

[0044] <Material> (1) Unused concrete (specific gravity: 2.27) Portland cement (JIS R 5210) 293 kg / m 3 ·Water 177kg / m 3 ·Fine aggregate (mountain sand) 530kg / m 3 · Fine aggregate (hard sandstone crushed sand) 363 kg / m 3 · Coarse aggregate (hard sandstone crushed stone 2013) 541 kg / m 3 · Coarse aggregate (hard sandstone crushed stone 1305) 360 kg / m 3 · Admixture (AE water reducer) 4.102 kg / m 3 (2) Washing water · Tap water (3) Polymer flocculant · Powdered anionic polymer flocculant composition (recycling treatment agent "Comburas (registered trademark)" manufactured by Teknika Corporation, product containing 28% by weight of anionic polymer flocculant) Weight average molecular weight (Mw) is 1.6×10 7 ~2.​​​​​​​​​​​​​​​​​​​​​​​​​​The weight (A) was calculated by adding the ) to the concrete container. Here, since the specific gravity of unused concrete is 2.27, the weight (A) of the unused concrete contained in the concrete container in this embodiment was calculated to be 2270 kg. [2] A small amount of unused concrete (a) was taken from the concrete container as a sample. In this example, 1 L (1 L × 2.27 = 2.27 kg) of unused concrete was taken for the minislump test. [3] Add the following amounts of tap water (b) to the sampled unused concrete (2.27 kg): [1] 0g (0.0v / v%, 60%) [2] 13g (1.3v / v%, 65%) [3] 28g (2.8v / v%, 70%) [4] 43g (4.3v / v%, 75%) [5] 57g (5.7v / v%, 80%) [6] 72g (7.2v / v%, 85%) [7] 87g (8.7v / v%, 90%) [8] 100g (10.0v / v%, 95%) [9] 115g (11.5v / v%, 100%) The mixture was added and stirred for approximately 10 minutes to prepare the hydrated concrete. The values ​​in parentheses after the amount added (g) indicate the hydration rate (v / v%) and cement ratio (%). [4] For each of the hydrated concrete [1] to [9], (A) powdered anionic polymer flocculant composition (c), or (B) liquid anionic polymer flocculant composition (c), in the amounts shown in [a] to [u] below: [a] 0.0g (0.000g, 0.000g) [b] 0.1g (0.028g, 0.040g) [c] 0.2g (0.056g, 0.080g) [d] 0.3g (0.084g, 0.120g) [e] 0.4g (0.112g, 0.160g) [f] 0.5g (0.140g, 0.200g) [g] 0.6g (0.168g, 0.240g) [h] 0.7g (0.196g, 0.280g) [i] 0.8g (0.224g, 0.320g) [j] 0.9g (0.252g, 0.360g) [k] 1.0g (0.280g, 0.400g) [l] 1.1g (0.308g, 0.440g) [m] 1.2g (0.336g, 0.480g) [n] 1.3g (0.364g, 0.520g) [o] 1.4g (0.392g, 0.560g) [p] 1.5g (0.420g, 0.600g) [q] 1.6g (0.448g, 0.640g) [r] 1.7g (0.476g, 0.680g) [s] 1.8g (0.504g, 0.720g) [t] 1.9g (0.532g, 0.760g) [u] 2.0g (0.560g, 0.800g) The samples were prepared by adding the ingredients and mixing with agitation for approximately 10 minutes. The amounts in parentheses after the amount added (g) indicate, respectively, (A) the net amount of anionic polymer flocculant added (g) from the powdered anionic polymer flocculant composition and (B) the net amount of anionic polymer flocculant added (g) from the liquid anionic polymer flocculant composition. Each sample was filled into the slump cone of a minislump tester and a minislump test was performed. [5] In the mini-slump test, samples with a slump value of 0 and voids observed on the surface were marked "○". Conversely, samples with a slump value that was not 0, or samples with a slump value of 0 but no voids observed on the surface, were marked "×". An example of the results of the mini-slump test is shown in Figure 2. Figure 2(a) is an example of a sample judged as "○", and Figure 2(b) is an example of a sample judged as "×". Then, for the results of the mini-slump test for all samples, the amount of water added was taken in the column direction (horizontal) and the amount of anionic polymer flocculant composition (anionic polymer flocculant) added was taken in the row direction (vertical) and a judgment map was created. The judgment map created based on the granulation test results of hydrated concrete using a powdered anionic polymer flocculant composition is shown in Figure 3, and the judgment map created based on the granulation test results of hydrated concrete using a liquid anionic polymer flocculant composition is shown in Figure 4.

[0047] <Calculation of input amount> Based on the weight of unused concrete samples [a(kg) = 2.27 kg], the amount of water added [b(g)], and the amount of polymer flocculant composition (liquid anionic polymer flocculant composition or powdered anionic polymer flocculant composition) added [c(g)] as shown in the judgment maps of Figures 3 and 4, the amount of tap water [B(g)] and the amount of polymer flocculant composition (liquid anionic polymer flocculant composition or powdered anionic polymer flocculant composition) added [C(g)] to the concrete container containing unused concrete [A(kg) = 2270 kg] were determined using the following formulas. B(g) = b × 2270 / 2.27 C(g) = c × 2270 / 2.27 For example, in the judgment map shown in Figure 3, column 2e (amount of water added (b) is 13g, and amount of powdered anionic polymer flocculant composition added (c) is 0.4g) has a judgment result of "○", so the amount of tap water added to the concrete container (B) and the amount of powdered anionic polymer flocculant composition added (C) are calculated as follows. B(g) = 13 × 2270 / 2.27 = 13000g(13kg) C(g) = 0.4 × 2270 / 2.27 = 400g(0.4kg) Similarly, for the columns where the other judgment result is "○", the amount of tap water to be added to the concrete container (B) and the amount of powdered anionic polymer flocculant composition to be added (C) are calculated. Furthermore, for all or some of the calculated add-in amounts, if the amount of tap water to be added (B) is taken in the column direction (horizontally) and the amount of polymer flocculant composition (polymer flocculant) to be added (C) is taken in the row direction (vertically), as in Figures 3 and 4, and these are mapped to create an add-in amount map in advance, workers at the construction site can check at a glance the appropriate amount of tap water to be added (B) and the amount of polymer flocculant composition (polymer flocculant) to be added (C) for unused concrete (A), thereby dramatically increasing work efficiency and convenience. Thus, according to the present invention, it is possible to properly process water-added concrete without relying on the intuition or experience of workers and to reuse it without waste.

[0048] <Consideration> From the results of the granulation test of the hydrated concrete in this embodiment, the following findings were obtained regarding the conditions for granulation of hydrated concrete. (1) Unused concrete (1m 3 If the amount of tap water added is 0 kg (for a total of 2270 kg), the amount of powdered anionic polymer flocculant composition to be added should be 400 to 1800 g (112 to 504 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 400 to 1700 g (160 to 680 g as anionic polymer flocculant). (2) Unused concrete (1m 3 If the amount of tap water added is 13 kg for a total volume of 2270 kg, the amount of powdered anionic polymer flocculant composition to be added should be 400 to 1800 g (112 to 504 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 400 to 1700 g (160 to 680 g as anionic polymer flocculant). (3) Unused concrete (1m 3If the amount of tap water added is 28 kg for a total volume of 2270 kg, the amount of powdered anionic polymer flocculant composition to be added should be 400 to 1700 g (112 to 476 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 500 to 1500 g (200 to 600 g as anionic polymer flocculant). (4) Unused concrete (1m 3 If the amount of tap water added is 43 kg for a total volume of 2270 kg, the amount of powdered anionic polymer flocculant composition to be added should be 500 to 1600 g (140 to 448 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 500 to 1400 g (200 to 560 g as anionic polymer flocculant). (5) Unused concrete (1m 3 If the amount of tap water added is 57 kg for a total volume of 2270 kg, the amount of powdered anionic polymer flocculant composition to be added should be 500 to 1500 g (140 to 420 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 500 to 1300 g (200 to 520 g as anionic polymer flocculant). (6) Unused concrete (1m 3 If the amount of tap water added is 72 kg (for a total volume of 2270 kg), the amount of powdered anionic polymer flocculant composition to be added should be 500-1200 g (140-336 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 800-1000 g (320-400 g as anionic polymer flocculant). (7) Unused concrete (1m 3 If the amount of tap water added is 87 kg for a total volume of 2270 kg, the amount of powdered anionic polymer flocculant composition to be added should be 800-1200 g (224-336 g as anionic polymer flocculant), and the amount of liquid anionic polymer flocculant composition to be added should be 800-1000 g (320-400 g as anionic polymer flocculant). (8) Under conditions other than those mentioned above, hydrated concrete does not granulate, making it difficult to process properly. (9) Based on the judgment maps in Figures 3 and 4, in the water addition process, it is necessary to set the water addition rate to the unused concrete to be less than 10v / v% and the cement ratio to be less than 95%. (10) Incidentally, even when a slump test is performed using a slump cone (upper inner diameter 100 mm × lower inner diameter 200 mm × height 300 mm) instead of the mini-slump test described above, a judgment map similar to those in Figures 3 and 4 can be created, and it has been confirmed that the appropriate amount of tap water to be added to unused concrete (A) (B) and the amount of polymer flocculant composition (polymer flocculant) to be added (C) can be calculated from this judgment map (data presentation omitted). [Industrial applicability]

[0049] The concrete processing method of the present invention can be used to reuse unused concrete (residual concrete, returned concrete) generated from civil engineering works, construction works, railway works, underground works, tunnel excavation works, etc.

Claims

1. A concrete treatment method in which unused concrete has been treated with a polymer flocculant, which is a water-hydrated concrete to which washing water has been added. A sampling process in which a small amount of unused concrete (a by weight) is taken as a sample from a storage unit that contains unused concrete (A by weight), A watering step is performed to prepare watered concrete by gradually adding and mixing washing water (b parts by weight) to the collected unused concrete within a predetermined range, The inspection process involves adding and mixing a polymer flocculant (c parts by weight) to the aforementioned hydrated concrete in stages within a predetermined range to prepare multiple samples, filling each sample into a slump cone, and performing a slump test. In the inspection step, a determination step is made in which the amount of polymer flocculant added (c parts by weight) to a sample in which the slump value after the slump test is 0 and voids are observed on the surface is confirmed, thereby determining that the water-added concrete has been granulated. A calculation step to calculate the amount of washing water (B parts by weight) and the amount of polymer flocculant (C parts by weight) to be added to the storage container that contains the unused concrete (A parts by weight), based on the aforementioned a parts by weight, b parts by weight, and c parts by weight, A method for treating concrete that includes [something].

2. The concrete treatment method according to claim 1, wherein the water-added concrete prepared in the water-adding step is set such that the water-adding ratio to the unused concrete is less than 10 v / v% and the cement ratio is less than 95%.

3. The concrete treatment method according to claim 1 or 2, wherein in the sampling step, the amount of unused concrete taken as a sample (a parts by weight) is 0.02% or more of the amount of unused concrete stored in the storage unit (A parts by weight).

4. The concrete treatment method according to claim 1 or 2, wherein the input step is performed to input the calculated amount of washing water (B parts by weight) and polymer flocculant (C parts by weight) into the container within 24 hours after sampling unused concrete (a parts by weight).

5. The concrete treatment method according to claim 1 or 2, wherein the polymer flocculant comprises an anionic polymer flocculant.

6. The concrete treatment method according to claim 1 or 2, wherein the size of the slump cone used in the slump test is 50 mm inner diameter at the top x 100 mm inner diameter at the bottom x 150 mm in height, or 100 mm inner diameter at the top x 200 mm inner diameter at the bottom x 300 mm in height.

7. The concrete processing method according to claim 1 or 2, wherein the storage unit is a drum mounted on an agitator vehicle, a mixer for ready-mixed concrete, a mixer for manufacturing ready-mixed concrete, a ready-mixed concrete bucket, or a ready-mixed concrete hopper.

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