JP4039992B2 - Prediction method of neutralization depth of concrete structures - Google Patents
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本発明は、コンクリート構造物の耐久性能の低下をきたす中性化の深さを予測する方法に関するものである。 The present invention relates to a method for predicting the depth of neutralization that causes a decrease in durability performance of a concrete structure.
鉄筋コンクリート構造物の多くはその外壁に仕上げが施されており、このような外装仕上塗材としては仕上塗料が最も一般的に採用されている。仕上塗料には意匠性、美観性の他、鉄筋コンクリート構造物の躯体の保護機能が求められており、保護機能としては主に防水が挙げられるが、この他にも構造物の耐久性の評価指数であるコンクリートの中性化を抑制する性能を有することが知られている。 Many reinforced concrete structures have a finish on the outer wall, and finish paint is most commonly used as such an exterior finish coating material. In addition to design and aesthetics, finishing paints are required to protect the frame of reinforced concrete structures. The protective function mainly includes waterproofing, but there are other indexes for evaluating the durability of structures. It is known to have the ability to suppress the neutralization of concrete.
コンクリートが中性化すると、鉄筋の保護機能が失われ、鉄筋が腐食し、その膨脹によってかぶりコンクリートにひび割れが生じる。このひび割れ部分から水や酸素、炭酸ガス等が侵入し、鉄筋の腐食が促進されてかぶりコンクリートの浮きや剥脱等の劣化を引き起こすことになる。そのため、鉄筋コンクリート構造物の中性化の深さを予測する方法が開発されている。 When the concrete becomes neutral, the protection function of the reinforcing bars is lost, the reinforcing bars corrode, and the expansion causes cracks in the cover concrete. Water, oxygen, carbon dioxide, or the like enters from the cracked portion, and the corrosion of the reinforcing bars is promoted to cause deterioration such as floating or exfoliation of the cover concrete. For this reason, methods for predicting the depth of neutralization of reinforced concrete structures have been developed.
即ち、躯体であるコンクリートの中性化深さについては、次式（１）に示すように、中性化期間ｔの平方根と中性化深さとの間に所謂ルートｔ則が成立することが知られており、この式（１）をもとに、仕上塗材による中性化抑制効果を、表面層をもつコンクリートとみなして、次式（Ａ）により表面に仕上塗材を装着している鉄筋コンクリートの中性化深さを推定する方法が提案されている（例えば、非特許文献１参照）。 That is, as to the neutralization depth of the concrete that is the frame, as shown in the following equation (1), a so-called root t rule may be established between the square root of the neutralization period t and the neutralization depth. Based on this formula (1), the neutralization suppression effect by the finish coating material is regarded as concrete with a surface layer, and the finish coating material is attached to the surface by the following formula (A) A method for estimating the neutralization depth of existing reinforced concrete has been proposed (for example, see Non-Patent Document 1).
しかしながら、コンクリートの表面に仕上塗材を塗布した場合、この仕上塗材自体も経年変化により劣化し、上記したコンクリートの中性化を抑制する性能も低下することが予想され、また、中性化抑制性能は仕上塗材の材質や塗厚によっても変化することが予想される。従って、コンクリートの中性化深さの推定に仕上塗材による中性化抑制効果を加味するためには、仕上塗材の劣化、材質、塗厚と中性化抑制性能を明らかにする必要があるが、上記式（Ａ）からはこの点についての定量的な評価ができず、そのため、仕上塗材を塗布している鉄筋コンクリート構造物の将来の中性化深さを精度良く推定することができず、コンクリート構造物の効率的な補修計画を立てることができないという問題点があった。 However, when a finish coating material is applied to the concrete surface, the finish coating material itself is also deteriorated due to aging, and the ability to suppress the above-described neutralization of concrete is also expected to decrease. The suppression performance is expected to change depending on the material and thickness of the finish coating material. Therefore, in order to add the neutralization suppression effect of the finish coating material to the estimation of the neutralization depth of concrete, it is necessary to clarify the deterioration, material, coating thickness and neutralization suppression performance of the finish coating material. However, from the above formula (A), it is impossible to quantitatively evaluate this point, and therefore it is possible to accurately estimate the future neutralization depth of the reinforced concrete structure to which the finish coating material is applied. There was a problem that it was impossible to make an efficient repair plan for concrete structures.
本発明は上記問題点を解決するために、劣化させた種々の仕上塗材で覆ったコンクリート試験体を用いて促進中性化試験を行い、仕上塗材の劣化と中性化抑制性能との関係について検討した結果、
イ）上記式（Ａ）がコンクリートの中性化予測式として妥当なものであること、
ロ）仕上塗材の同じ劣化状態においては、仕上塗材の種類にかかわらず、仕上塗材の樹脂厚と中性化抵抗Ｒとの間に比例関係があること、
ハ）仕上塗材の劣化が進行するほど、中性化抑制性能は低下すること、
以上の知見を得てなされたものである。
In order to solve the above-mentioned problems, the present invention performs an accelerated neutralization test using concrete specimens covered with various deteriorated finish coating materials, and demonstrates that the finish coating material deterioration and neutralization suppression performance As a result of examining the relationship,
B) The above formula (A) is valid as a concrete neutralization prediction formula,
B) In the same deterioration state of the finish coating material, there is a proportional relationship between the resin thickness of the finish coating material and the neutralization resistance R regardless of the type of the finish coating material.
C) Neutralization suppression performance decreases as the finish coating material deteriorates.
The above findings have been made.
即ち、本発明のコンクリート構造物の中性化深さの予測方法は、請求項１に記載したように、仕上塗材を塗布したコンクリート構造物の中性化深さの予測方法であって、仕上塗材の全塗厚に仕上塗材中に含まれる樹脂成分の割合を乗じたものである樹脂塗膜厚さの異なる各種仕上塗材を施した各コンクリート試験体を用意し、この各試験体に各仕上塗材の材齢に相当する劣化を与えた後、この劣化を与えた各試験体に対し各材齢に相当する中性化促進試験を行って各材齢及び各樹脂塗膜厚さでの中性化深さを測定する工程と、測定した中性化深さに基づき、下記の式（Ａ）により各材齢及び各樹脂塗膜厚さでの中性化抵抗を求出する工程と、求出した中性化抵抗に基づき、単位樹脂塗膜厚さ当たりの中性化抵抗と材齢の関係を直線近似式で表しておく工程と、中性化深さを予測すべきコンクリート構造物の仕上塗材の樹脂塗膜厚と材齢と測定する工程と、測定された仕上塗材の樹脂塗膜厚と材齢とから上記直線近似式に基づいて中性化抵抗を求める工程と、求められた中性化抵抗を基に下記式（Ａ）によりコンクリート構造物の中性化深さを予測することを特徴とする。
That is, the prediction method of the neutralization depth of the concrete structure of the present invention is a prediction method of the neutralization depth of the concrete structure to which the finish coating material is applied, as described in
請求項１に係る発明によれば、仕上塗材の材齢と仕上塗材の塗厚とから仕上塗材を塗布したコンクリート構造物の中性化抵抗を求め、求められた中性化抵抗を基にコンクリート構造物の中性化深さを予測するものであるから、表面に仕上塗材を塗布しているコンクリート構造物の将来の中性化深さを簡単に且つ正確に推定することができ、コンクリート構造物の補修計画を効率的に立てることができる。 According to the first aspect of the invention, the neutralization resistance of the concrete structure to which the finish coating material is applied is obtained from the age of the finish coating material and the coating thickness of the finish coating material, and the obtained neutralization resistance is obtained. Because it predicts the neutralization depth of a concrete structure based on it, it is possible to easily and accurately estimate the future neutralization depth of a concrete structure with a finish coating applied to the surface. It is possible to make a repair plan for concrete structures efficiently.
さらに、仕上塗材を塗布したコンクリート構造物における仕上塗材の単位塗厚当たりの中性化抵抗と仕上塗材の材齢との関係を直線近似式で表しておく工程と、中性化深さを予測すべきコンクリート構造物の仕上塗材の塗厚と材齢とを測定する工程と、測定された仕上塗材の樹脂塗膜厚と材齢とから上記直線近似式に基づいて中性化抵抗を求める工程と、求められた中性化抵抗を基に、コンクリート構造物の中性化深さを予測する工程とからなるものであるから、予め、仕上塗材を塗布したコンクリート構造物における仕上塗材の単位塗厚当たりの中性化抵抗と仕上塗材の材齢との関係を直線近似式で表しておくので、コンクリート構造物の仕上塗材の塗厚と材齢とを測定するだけで、その測定された仕上塗材の塗厚と材齢とから上記直線近似式に基づいてこのコンクリート構造物の中性化抵抗を簡単に且つ正確に求めることができ、この中性化抵抗からコンクリート構造物の中性化深さを予測することができる。 In addition, the process of expressing the relationship between the neutralization resistance per unit coating thickness of the finishing coating material and the age of the finishing coating material in a concrete structure coated with the finishing coating material using a linear approximation formula, and the neutralization depth Based on the above linear approximation formula based on the process of measuring the coating thickness and age of the finish coating material of the concrete structure whose thickness should be predicted, and the measured resin coating thickness and age of the finishing coating material Because it consists of the process of obtaining the resistance to neutralization and the process of predicting the neutralization depth of the concrete structure based on the obtained neutralization resistance, the concrete structure to which the finish coating material has been applied in advance Since the relation between the neutralization resistance per unit coating thickness of the finish coating material and the age of the finish coating material is expressed by a linear approximation formula, the thickness and age of the finish coating material for concrete structures are measured. simply, the straight line near and a coating thickness Metropolitan ages of topcoat material that is the measured Neutralization resistance of the concrete structure easily and accurately it can be determined based on equation can predict neutralization depth of the concrete structure from the neutralization resistance.
また、上記仕上塗材の塗厚は、仕上塗材の全塗厚に仕上塗材中に含まれる樹脂成分の割合を乗じたものであるから、コンクリート構造物の仕上塗材の塗厚のうち、中性化抵抗に寄与する部分の厚さを正確に求めることができる。 Also, the coating thickness of the above finish coating material is obtained by multiplying the total coating thickness of the finish coating material by the ratio of the resin component contained in the finish coating material. The thickness of the portion contributing to the neutralization resistance can be accurately obtained.
その上、上記式（Ａ）によって経年変化により劣化するコンクリート構造物の中性化深さを数値的に容易に且つ正確に求めることができ、コンクリート構造物の補修時期を予め計画しておくことができる。 In addition, the neutralization depth of a concrete structure that deteriorates over time can be determined numerically easily and accurately by the above formula (A), and the repair time for the concrete structure should be planned in advance. Can do.
次に、本発明を実施するための最良の形態について説明すると、鉄筋コンクリート造建築物等の外壁表面にアクリル系樹脂等の仕上塗材を吹付塗装などによって塗装してなる新設或いは既設のコンクリート構造物の中性化深さを予測するに際して、まず、劣化させた種々の仕上塗材で覆っているコンクリート試験体を用いてこれらのコンクリート試験体の促進中性化試験を行い、仕上塗材の劣化と中性化抑制性能との関係について検討した。 Next, the best mode for carrying out the present invention will be described. A new or existing concrete structure in which a finish coating material such as an acrylic resin is coated on the outer wall surface of a reinforced concrete structure or the like by spray coating or the like. When predicting the neutralization depth, first of all, concrete samples covered with various deteriorated finish coating materials were used to conduct accelerated neutralization tests on these concrete test samples, and deterioration of the finish coating materials. And the relation between neutralization suppression performance was investigated.
その結果、次式（Ａ）がコンクリート構造物の中性化予測式として妥当なものであること、同じ劣化状態において、仕上塗材の種類にかかわらず、仕上塗材の塗厚（樹脂厚）と上記式（Ａ）における中性化抵抗Ｒとの間に比例関係があること、仕上塗材の劣化が進行するほどコンクリート構造物に対する中性化抑制性能は低下することの知見を得た。 As a result, the following formula (A) is valid as a neutralization prediction formula for concrete structures, and in the same deterioration state, the coating thickness (resin thickness) of the finish coating material regardless of the type of finish coating material And the neutralization resistance R in the above formula (A), and the knowledge that the neutralization suppression performance for concrete structures decreases as the finish coating material progresses.
このようなコンクリート試験体の促進中性化試験を上記新設或いは既設のコンクリート構造物の中性化深さの予測に採用して、まず、該コンクリート表面に塗布している仕上塗材の材齢、即ち、コンクリート構造物の築造年数とこの仕上塗材の塗厚とからコンクリート構造物の中性化抵抗を求め、求められた中性化抵抗から上記式（Ａ）に基づいてコンクリート構造物の中性化深さを予測するものである。 Adopting such accelerated neutralization test of concrete specimens to predict the neutralization depth of the above-mentioned new or existing concrete structures, first, the age of the finish coating material applied to the concrete surface That is, the neutralization resistance of the concrete structure is obtained from the building age of the concrete structure and the coating thickness of the finish coating material, and the concrete structure is calculated based on the above formula (A) from the obtained neutralization resistance. It predicts the depth of neutralization.
この場合、予め、仕上塗材を塗布したコンクリート構造物における仕上塗材の単位塗厚当たりの中性化抵抗と仕上塗材の材齢との関係を示す図又は表を作成して準備しておく。このような図又は表を準備しておくことによって、コンクリート構造物の仕上塗材の塗厚と材齢とを測定するだけで、該塗厚と材齢とから上記図又は表に基づいてコンクリート構造物の中性化抵抗を簡単且つ確実に求めることができ、求められた中性化抵抗を基に、上記式（Ａ）によりコンクリート構造物の中性化深さを予測することができる。 In this case, prepare in advance a diagram or table showing the relationship between the neutralization resistance per unit coating thickness of the finish coating material and the age of the finish coating material in the concrete structure to which the finish coating material has been applied. deep. By preparing such a figure or table, it is only necessary to measure the thickness and age of the finish coating material of the concrete structure, and based on the above figure or table from the thickness and material age, The neutralization resistance of the structure can be easily and reliably obtained, and the neutralization depth of the concrete structure can be predicted from the above formula (A) based on the obtained neutralization resistance.
即ち、仕上塗材を塗布したコンクリート構造物における仕上塗材の単位塗厚当たりの中性化抵抗と仕上塗材の材齢との関係を示す図又は表を予め求めて準備しておく工程と、コンクリート構造物の仕上塗材の塗厚と材齢とを測定して中性化深さを予測する工程と、測定された仕上塗材の塗厚と材齢とから上記図又は表に基づいて中性化抵抗を求める工程と、求められた中性化抵抗を基に、コンクリート構造物の中性化深さを予測する工程とからなる仕上塗材を塗布したコンクリート構造物の中性化深さの予測方法である。 That is, a step of obtaining and preparing in advance a diagram or table showing the relationship between the neutralization resistance per unit coating thickness of the finish coating material and the age of the finish coating material in a concrete structure coated with the finish coating material; Based on the above figure or table from the process of predicting the neutralization depth by measuring the coating thickness and age of the finish coating material of the concrete structure, and the measured coating thickness and age of the finishing coating material Neutralization of a concrete structure with a finish coating material consisting of a process for obtaining neutralization resistance and a process for predicting the neutralization depth of the concrete structure based on the obtained neutralization resistance This is a depth prediction method.
次に、本発明をさらに具体的に以下の試験例に基づいて説明する。まず、試験体を製作する。その製作方法は次の通りである。
〔試験体の製作方法〕
劣化試験に用いる試験体にはサンシャインウェザーメータ内に設置できるように大きさ70×150mm 、厚さ５mmのモルタル板を用いた。劣化試験は、化学的劣化試験を先行して行い、その後、化学劣化した試験体のモルタル板裏面にコンクリートを後打ちした試験体を新たに作製し、その試験体に物理的劣化を与えた。後打ちコンクリートはモルタル板を底面として打ち込み、その際、塗装面にペーストが付着しないように養生した。後打ちコンクリートの使用材料と調合を表１に示す。
Next, the present invention will be described more specifically based on the following test examples. First, a test body is manufactured. The manufacturing method is as follows.
[Production method of specimen]
The specimen used for the deterioration test was a mortar plate having a size of 70 × 150 mm and a thickness of 5 mm so that it could be installed in the sunshine weather meter. In the deterioration test, a chemical deterioration test was performed in advance, and then, a test specimen in which concrete was post-placed on the back of the mortar plate of the chemically deteriorated test specimen was newly produced, and physical deterioration was given to the test specimen. Post-cast concrete was cast with the mortar board as the bottom, and was cured so that the paste would not adhere to the painted surface. Table 1 shows the materials and composition of post-cast concrete.
〔実験因子と水準〕
実験因子と水準及び試験体記号を表２に示す。上記モルタル板表面に塗布する仕上塗材は耐久性能、使用実績等を考慮し、JIS A 6909に適合した３種類を選定した。材質はいずれもアクリル系のものを用いた。塗厚さは標準仕様の塗厚さと、薄塗りの２種類とした。仕上塗材を劣化させる要因は、現実の劣化状況を考慮し、紫外線や降雨による化学的劣化と温熱変化に伴う躯体の伸縮による物理的劣化とを合わせた複合劣化とした。化学的劣化はサンシャインウェザーメータを用い（光源：サンシャインカーボンアーク燈、ブラックパネル温度：約63℃、降雨時間：120 分のうち18分）、照射1500時間（劣化６年に相当する）、3000時間（劣化12年相当する）とした。
[Experimental factors and levels]
Table 2 shows experimental factors, levels, and specimen symbols. Three types of finish coating materials that conform to JIS A 6909 were selected in consideration of durability performance, actual use, etc. as the finish coating material to be applied to the surface of the mortar board. Acrylic materials were used for all materials. There were two types of coating thickness: standard coating thickness and thin coating. The factor that deteriorates the finish coating material is a composite deterioration that combines the chemical deterioration due to ultraviolet rays and rainfall, and the physical deterioration due to the expansion and contraction of the frame accompanying thermal changes, considering the actual deterioration situation. For chemical degradation, use a sunshine weather meter (light source: sunshine carbon arc lamp, black panel temperature: about 63 ° C, rainfall time: 18 minutes out of 120 minutes), irradiation 1500 hours (corresponding to 6 years of degradation), 3000 hours (Corresponding to 12 years of deterioration).
その根拠は下記文献Ａに仕上塗料における沖縄県糸満市での屋外曝露試験結果とサンシャインウェザーメータによる化学的劣化促進試験結果との比較が開示されており、それによれば、サンシャインウェザーメータの照射時間600 時間が糸満市での曝露１年に相当することが示されている。一方、下記文献Ｂには日本各地での仕上塗料の屋外曝露試験結果が開示されており、それによれば、化学的劣化度を表す光沢残存率（これが低い程、劣化が進んでいる）は、関東圏（青梅市、つくば市）の４年曝露時の値が糸満市での約1.6 年曝露時の値と同じになっており、糸満市での１年曝露は関東圏での1.6 ／４＝0.4 年に相当する。これを文献Ａに基づきサンシャインウェザーメータの照射時間に換算すると250時間となる。よって、250 ×６＝1500時間が関東での６年曝露、250 ×12＝3000時間が関東での12年曝露に相当することになる。 The basis for this is disclosed in the following document A, which compares the results of outdoor exposure tests for finishing paints in Itoman City, Okinawa Prefecture with the results of chemical degradation acceleration tests using sunshine weathermeters. It has been shown that 600 hours corresponds to one year of exposure in Itoman City. On the other hand, the following document B discloses the results of outdoor exposure test of finishing paints in various parts of Japan, and according to it, the gloss residual ratio indicating the degree of chemical deterioration (the lower this is, the more advanced the deterioration) is, The values in the Kanto area (Ome City, Tsukuba City) when exposed for four years are the same as those when exposed for approximately 1.6 years in Itoman City. The annual exposure in Itoman City is 1.6 / 4 in the Kanto area. = Equivalent to 0.4 years. When this is converted into the irradiation time of the sunshine weather meter based on the document A, it becomes 250 hours. Therefore, 250 × 6 = 1500 hours corresponds to 6 years of exposure in the Kanto region, and 250 × 12 = 3000 hours corresponds to 12 years of exposure in the Kanto region.
〔文献Ａ〕：竹内博幸ら、「外壁用塗材の耐候性能評価に関する研究その28」
日本建築学会大会学術公園梗概集、1994年９月。
〔文献Ｂ〕：渡邉康則ら、「外壁用塗材の耐候性能評価に関する研究その23」
日本建築学会大会学術公園梗概集、1994年９月。
[Reference A]: Hiroyuki Takeuchi et al., “Study on weather resistance performance evaluation of coating materials for exterior walls, 28”
Architectural Institute of Japan Annual Meeting of Parks, September 1994.
[Document B]: Yasunori Watanabe et al., “Study on Weatherability Evaluation of Coating Materials for Exterior Wall, Part 23”
Architectural Institute of Japan Annual Meeting of Parks, September 1994.
物理的劣化は躯体の伸縮を想定した引張と圧縮の曲げひずみを振動試験機で与えた（ひずみ導入方法：曲げ応力繰返し（片振り）、曲げひずみ量（ひずみ度）：約80×10-6、振動数：５Hz）。振動回数は日内の温度変化による伸縮を１日一回（明け方から昼過ぎまでは伸（引張）、昼過ぎから明け方までは縮（圧縮）であり、引張・圧縮の双方2190回（劣化６年に相当する）、4380回（劣化12年に相当とする）の２水準とした。 For physical deterioration, tensile and compression bending strains assuming the expansion and contraction of the frame were applied using a vibration tester (strain introduction method: repeated bending stress (single swing), bending strain amount (strain degree): approx. 80 × 10 -6 , Frequency: 5 Hz). The number of vibrations is once a day for expansion and contraction due to temperature changes within the day (stretching (tensile) from early morning to early afternoon, and shrinking (compressing) from early afternoon to early morning. 2) 4380 times (equivalent to 12 years of deterioration).
〔仕上塗材の塗厚さ〕
各モルタル板に施した仕上塗材の平均厚さと、仕上塗材に含まれている樹脂質量に対する平均塗厚さ（以下、樹脂塗膜厚さと略す）を表３に示す。量塗厚さは各試験体において測定した塗布質量を基に推定した。塗厚さは仕上塗材の種類別に比較すると、防水形複層塗材Ｅが最も大きく、次いで防水形外装薄塗材Ｅ、複層塗材Ｅの順である。
[Finish coating thickness]
Table 3 shows the average thickness of the finish coating material applied to each mortar plate and the average thickness (hereinafter abbreviated as resin coating thickness) with respect to the resin mass contained in the finish coating material. The quantity coating thickness was estimated based on the coating mass measured in each specimen. The coating thickness is the largest for the waterproof multilayer coating material E, followed by the waterproof exterior thin coating material E, and then the multilayer coating material E in comparison with the type of finish coating material.
〔中性化促進試験〕
中性化促進試験は、仕上塗材に所定の劣化を与えた後の試験体を中性化試験槽（温度：20±２℃、相対湿度：60±５％、C02 濃度：５±0.2 ％）に入れ、所定材齢にて、試験体を切断し切断面の３点の中性化深さを測定し、平均値を中性化深さとした。
[Neutralization promotion test]
Neutralization accelerated test neutralization test chamber of the test body after giving a predetermined deterioration in the topcoat material (temperature: 20 ± 2 ° C., relative humidity: 60 ± 5%, C0 2 concentration: 5 ± 0.2 %), The specimen was cut at a predetermined age, and the neutralization depth of the three points of the cut surface was measured, and the average value was defined as the neutralization depth.
〔中性化促進試験結果〕
本試験においては、仕上げなしの場合と、各種仕上塗材を施した場合の上記式（Ａ）と実験値の比較から、中性化抑制効果の定量的評価を試みた。仕上塗材の複合劣化０年（＝劣化なし）、６年、12年の場合の標準塗厚さ試験体の中性化傾向および上記式（Ａ）との比較をそれぞれ図１〜図３に示す。なお、式（Ａ）の中性化抵抗は、実験値を用いて最小２乗法により算出した。仕上塗材毎に中性化抵抗を比較した場合、複層塗材、防水形外装薄塗材、防水形複層塗材の順で中性化の抑制効果は高くなった。また、仕上塗材の劣化程度が大きいほど抑制効果の低下も大きい傾向にあった。中性化傾向を上記式（Ａ）と比較すると、実験値のばらつきがあるものの、式（Ａ）の中性化傾向と実験値はほぼ合致している。従って、仕上塗材が劣化した場合でも、式（Ａ）でコンクリートの中性化傾向を推定できると考えられる。
[Neutralization promotion test results]
In this test, an attempt was made to quantitatively evaluate the neutralization-inhibiting effect from the comparison between the above formula (A) and the experimental values when there was no finishing and when various finishing coating materials were applied. Fig. 1 to Fig. 3 compare the neutralization tendency of the standard coating thickness test specimens in the case of composite degradation of finish coating materials of 0 years (= no degradation), 6 years, and 12 years, and the above formula (A), respectively. Show. In addition, the neutralization resistance of Formula (A) was calculated by the least square method using experimental values. When the neutralization resistance was compared for each finish coating material, the neutralization suppression effect increased in the order of the multilayer coating material, the waterproof exterior thin coating material, and the waterproof multilayer coating material. In addition, as the degree of deterioration of the finish coating material increases, the suppression effect tends to decrease. Comparing the neutralization tendency with the above formula (A), although there is a variation in the experimental value, the neutralization tendency of the formula (A) and the experimental value almost coincide. Therefore, even when the finish coating material is deteriorated, it is considered that the neutralization tendency of the concrete can be estimated by the equation (A).
〔仕上塗材の塗厚さと中性化抑制効果〕
複合劣化における、樹脂塗膜厚さと式（Ａ）の中性化抵抗との関係を図４に示す。樹脂塗膜厚さが大きいほど中性化抵抗は大きくなり、経年劣化が進むほど小さくなる。複合劣化を受けた場合、中性化抵抗は樹脂塗膜厚さに対してほぼ直線的に増加する傾向にあり、中性化抵抗は、樹脂塗膜厚さと相関があると考えられる。そこで、中性化抵抗を樹脂塗膜厚さとの関係から直線近似式で表した。近似式を上記図４に示す。同様に経年劣化０年（劣化なし）についても中性化抵抗と樹脂塗膜厚さとの関係を直線近似式で表した。
[Finish thickness and neutralization suppression effect of finish coating materials]
FIG. 4 shows the relationship between the resin coating thickness and the neutralization resistance of the formula (A) in the composite deterioration. The neutralization resistance increases as the resin coating thickness increases, and decreases as the aging progresses. When subjected to complex deterioration, the neutralization resistance tends to increase almost linearly with respect to the resin coating thickness, and the neutralization resistance is considered to be correlated with the resin coating thickness. Therefore, the neutralization resistance was expressed by a linear approximation formula from the relationship with the resin coating thickness. The approximate expression is shown in FIG. Similarly, the relationship between the neutralization resistance and the resin coating thickness was expressed by a linear approximation formula with respect to 0 years of aging (no deterioration).
図４に示す劣化年数毎の近似式の傾き（樹脂塗膜厚さに対する中性化抵抗）と劣化年数の関係を図５に示す。樹脂塗膜厚さに対する中性化抵抗と劣化年数の関係を直線近似した場合、中性化抵抗は劣化年数と樹脂塗膜厚さから次式（２）と（３）で表せる。 FIG. 5 shows the relationship between the slope of the approximate expression for each deterioration year shown in FIG. 4 (neutralization resistance with respect to the resin coating film thickness) and the deterioration year. When the relationship between the neutralization resistance and the age of deterioration with respect to the resin coating thickness is linearly approximated, the neutralization resistance can be expressed by the following equations (2) and (3) from the deterioration age and the resin coating thickness.
〔仕上塗材の経年劣化を考慮した中性化予測式〕
実験結果から、仕上塗材に劣化が生じた場合のコンクリートの中性化抵抗は上記式（Ａ）でおおよそ表せ、また、中性化抵抗は樹脂塗膜厚さと劣化年数から推定できると考えられる。そこで、式（Ａ）に経時的評価を入れた次式（４）を用いて、ステップ毎に式（５）から見かけの材齢を、式（７）（８）から中性化抵抗を算出し、中性化の進行を予測する方法を提案した。ここでは、材齢は「年」で表し、炭酸ガス濃度５％の促進中性化試験の結果から得た中性化抵抗Ｒを式（６）に示す屋外での想定炭酸ガス濃度（＝0.03％）で補正した中性化抵抗R'を用いて算出する。適用条件として、仕上塗材は13年以内に塗り替えることとし、また、中性化抵抗Ｒの算出では、樹脂塗膜厚さに仕上塗材施工における塗厚さのばらつきを考慮した係数を乗じることとした。
[Neutralization prediction formula considering aging deterioration of finishing coating materials]
From the experimental results, it is considered that the neutralization resistance of concrete when the finish coating material is deteriorated can be approximately expressed by the above formula (A), and the neutralization resistance can be estimated from the resin coating thickness and the deterioration years. . Therefore, using the following equation (4), which is evaluated over time in equation (A), the apparent material age is calculated from equation (5) and neutralization resistance is calculated from equations (7) and (8) for each step. And proposed a method for predicting the progress of neutralization. Here, the age of the material is expressed in “years”, and the neutralization resistance R obtained from the result of the accelerated neutralization test with a carbon dioxide concentration of 5% is assumed as the assumed outdoor carbon dioxide concentration (= 0.03) shown in Equation (6). %) Is used to calculate the neutralization resistance R ′. As applicable conditions, finish coating materials should be repainted within 13 years, and the neutralization resistance R should be calculated by multiplying the resin coating thickness by a coefficient that takes into account the coating thickness variation in the finish coating construction. It was.
提案した中性化予測の計算例として算定条件と、外壁部分に仕上塗材を施した場合と仕上げなしの打放しの場合における中性化深さの進行予測を図６に示す。仕上塗材は複層塗材Ｅとし、13年目毎に塗り替える計画とした。仕上塗材施工時の塗厚さのばらつきを表す係数は0.5 とした。仕上塗材を施した場合の中性化深さは、経過年数60年で打放しの場合の約50％程度となる。 FIG. 6 shows calculation conditions as a calculation example of the proposed neutralization prediction, and progress prediction of the neutralization depth in the case where the outer wall portion is finished with a finish coating material and in the case where the finish is released without finishing. The finish coating material was a multi-layer coating material E, and it was planned to be repainted every 13th year. The coefficient representing the variation in coating thickness when finishing coating was applied was set to 0.5. The neutralization depth when the finish coating material is applied is about 50% of the case where it is released in 60 years.
仕上塗材による中性化の抑制効果について実験的に検討した結果、以下の知見が得られた。仕上塗材に含まれる樹脂量から換算した樹脂塗膜厚で、中性化に対する抵抗性を推定できる。実験結果から上記式（Ａ）を基に仕上塗材の経年劣化を考慮した中性化進行の予測式を提案した。 The following findings were obtained as a result of an experimental study on the neutralization suppression effect by the finish coating material. The resistance to neutralization can be estimated by the resin coating thickness converted from the amount of resin contained in the finish coating material. From the experimental results, a prediction formula for the progress of neutralization was proposed in consideration of the aging of the finish coating material based on the above formula (A).
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| JP6616735B2 (en) * | 2016-05-23 | 2019-12-04 | 日本電信電話株式会社 | Method for evaluating long-term reliability of resin concrete, method for evaluating CO2 concentration-dependent strength decrease time, and method for estimating strength decrease behavior |
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