王 彬,楊勇新,岳清瑞,曾 濱
(中冶建筑研究總院有限公司,北京 100088)
CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型評(píng)價(jià)及應(yīng)用
王 彬,楊勇新,岳清瑞,曾 濱
(中冶建筑研究總院有限公司,北京 100088)
在初步建立CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型基礎(chǔ)上,對(duì)該模型典型因子影響材料強(qiáng)度權(quán)重進(jìn)行研究評(píng)價(jià),根據(jù)結(jié)果提出CFRP筋制備過(guò)程中強(qiáng)度補(bǔ)償機(jī)制。結(jié)果表明:典型因子碳纖維拉伸強(qiáng)度(σf)和體積分?jǐn)?shù)(Vf)對(duì)CFRP筋拉伸強(qiáng)度影響最為顯著(影響率為39.1%~46.7%和43.5%~52.6%),是決定CFRP筋拉伸性能的最重要因素。公稱(chēng)直徑(D)對(duì)CFRP筋拉伸強(qiáng)度存在一定程度影響(影響率7.1%~15.4%)?;w樹(shù)脂強(qiáng)度(σm)對(duì)CFRP筋拉伸強(qiáng)度影響不明顯(影響率0.3%~1.0%),相比其他三種因素,可近似忽略。依據(jù)預(yù)測(cè)模型典型因子強(qiáng)度補(bǔ)償規(guī)律,可較方便推測(cè)CFRP筋組分碳纖維強(qiáng)度及體積分?jǐn)?shù)參數(shù)。
CFRP筋;拉伸強(qiáng)度;預(yù)測(cè);評(píng)價(jià)
Abstract: Based on the prediction formula of tensile strength for CFRP bars, weight of influence of the typical factors on material strength was evaluated, and the mechanism of intensity compensation in the process of preparing CFRP bar was proposed. The results show that the effect of typical factors of carbon fiber tensile strength and volume fraction effect on the tensile strength of CFRP bars is most significant (influence rate:39.1%-46.7% and 43.5-52.6%). They are the most important factors that determine the tensile properties of CFRP bars. Nominal diameter has a certain effect on the tensile strength of CFRP bars (influence rate: 7.1%-15.4%). Influence of resin matrix strength on the tensile strength of the CFRP bar is not obvious (influence rate: 0.3%-1.0%). Compared to the other three factors, the influence of the tensile strength of resin can be nearly neglected. According to the intensity compensation rule of the typical factors, the strength and volume fraction of carbon fiber in CFRP bars can be easily inferred.
Keywords:CFRP bars;tensile strength;prediction;evaluation
碳纖維增強(qiáng)復(fù)合材料筋(CFRP筋)具有優(yōu)異的力學(xué)性能和耐腐蝕特性,在橋梁、巖土、隧道、島礁等工程建設(shè)領(lǐng)域,作為新型結(jié)構(gòu)材料,可部分代替鋼筋,應(yīng)用前景良好,受到國(guó)內(nèi)外專(zhuān)家學(xué)者的普遍關(guān)注[1-3]。
目前我國(guó)CFRP筋產(chǎn)品規(guī)格型號(hào)繁多,質(zhì)量懸殊較大,深入推進(jìn)其在工程建設(shè)領(lǐng)域的規(guī)范、安全應(yīng)用具有諸多困難[4-5]。
基于經(jīng)典復(fù)合材料混合理論,結(jié)合實(shí)驗(yàn)研究提出的CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型σ=0.95×[σfVf+σm(1-Vf)]-B×D[6],為工程設(shè)計(jì)應(yīng)用提供了材料制備的有效指導(dǎo)。在此基礎(chǔ)上,本工作借助大數(shù)據(jù)分析手段,結(jié)合歸一化處理方法,對(duì)該模型的典型因子影響權(quán)重進(jìn)行研究評(píng)價(jià),提出典型因子影響的CFRP筋強(qiáng)度補(bǔ)償機(jī)制及產(chǎn)品組分參數(shù)預(yù)測(cè)評(píng)估方法建議,以期為調(diào)控低成本高強(qiáng)度質(zhì)量穩(wěn)定的CFRP筋制備生產(chǎn)以及工程應(yīng)用的高效檢測(cè)評(píng)估提供理論基礎(chǔ)。
CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型:σ=0.95×[σfVf+σm(1-Vf)]-B×D,其中σf,Vf分別表示碳纖維拉伸強(qiáng)度和體積分?jǐn)?shù);σm為基體樹(shù)脂拉伸強(qiáng)度;D為CFRP筋公稱(chēng)直徑;B為由直徑D帶來(lái)的強(qiáng)度折損系數(shù)(B一般在34~40MPa/mm)[6]。
以CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型為基礎(chǔ),深入研究典型因子對(duì)CFRP筋拉伸強(qiáng)度的影響權(quán)重。這里,對(duì)典型因子影響的CFRP筋拉伸強(qiáng)度變化進(jìn)行歸一化處理,以建立不同量綱典型因子影響材料強(qiáng)度權(quán)重的可比關(guān)系。
定義σ′為歸一化處理后CFRP筋拉伸強(qiáng)度變化率,即:
(1)
式中:σmax和σmin分別表示改變一種典型因素的指標(biāo)參數(shù),對(duì)應(yīng)CFRP筋拉伸強(qiáng)度預(yù)測(cè)最大值和最小值。則該模型中典型因子對(duì)CFRP筋拉伸強(qiáng)度的影響權(quán)重,可借助σ′進(jìn)行比較。
1.1碳纖維拉伸強(qiáng)度σf
依據(jù)式(1),改變碳纖維拉伸強(qiáng)度σf,對(duì)應(yīng)CFRP筋拉伸強(qiáng)度變化率:
(2)
式中:A是σm,Vf,D三種因素的共同函數(shù),影響碳纖
依據(jù)目前市場(chǎng)常規(guī)CFRP筋組分參數(shù)指標(biāo)值范圍,其中:碳纖維拉伸強(qiáng)度σf為3600~4900MPa,碳纖維體積分?jǐn)?shù)Vf為50%~70%,基體環(huán)氧樹(shù)脂拉伸強(qiáng)度σm為42~70MPa,CFRP筋公稱(chēng)直徑D為6~12mm,直徑折損系數(shù)B取34MPa/mm,則:
(1)當(dāng)基體樹(shù)脂拉伸強(qiáng)度σm=70MPa,碳纖維體積分?jǐn)?shù)Vf=70%,CFRP筋公稱(chēng)直徑D=6mm時(shí),A取最大值:
取碳纖維拉伸強(qiáng)度σfmax=4900MPa,σfmin=3600MPa,則:
(2)當(dāng)基體樹(shù)脂拉伸強(qiáng)度σm=42MPa,碳纖維體積分?jǐn)?shù)Vf=50%,CFRP筋公稱(chēng)直徑D=12mm時(shí),A取最小值:
1.2碳纖維體積分?jǐn)?shù)Vf
依據(jù)式(1),改變碳纖維體積分?jǐn)?shù)Vf,對(duì)應(yīng)CFRP筋拉伸強(qiáng)度變化率:
(3)
(4)
(1)當(dāng)基體樹(shù)脂拉伸強(qiáng)度σm=70MPa,碳纖維拉伸強(qiáng)度σf=3600MPa時(shí),A取最大值:
(2)當(dāng)基體樹(shù)脂拉伸強(qiáng)度σm=42MPa,碳纖維拉伸強(qiáng)度σf=4900MPa時(shí),A取最小值:
(5)
取碳纖維體積分?jǐn)?shù)Vfmax=70%,Vfmin=50%
1.3 CFRP筋公稱(chēng)直徑D
依據(jù)式(1),改變公稱(chēng)直徑D,對(duì)應(yīng)CFRP筋拉伸強(qiáng)度變化率:
(6)
(1)當(dāng)碳纖維拉伸強(qiáng)度σf=4900MPa,碳纖維體積分?jǐn)?shù)Vf=70%,基體樹(shù)脂拉伸強(qiáng)度σm=70MPa時(shí),A取最大值:
Amax=0.95×[σfVf+σm(1-Vf)]= 0.95×[4900×70%+70×(1-70%)]=3278
(2)當(dāng)碳纖維拉伸強(qiáng)度σf=3600MPa,碳纖維體積分?jǐn)?shù)Vf=50%,基體樹(shù)脂拉伸強(qiáng)度σm=42MPa時(shí),A取最小值:
Amin=0.95×[σfVf+σm(1-Vf)]= 0.95×[3600×50%+42×(1-50%)]=1730
1.4基體樹(shù)脂拉伸強(qiáng)度σm
依據(jù)式(1),改變基體樹(shù)脂σm,對(duì)應(yīng)CFRP筋拉伸強(qiáng)度變化率:
(7)
(1)當(dāng)碳纖維拉伸強(qiáng)度σf=4900MPa,碳纖維體積分?jǐn)?shù)Vf=70%,CFRP筋公稱(chēng)直徑D=6mm時(shí),A取最大值:
取基體樹(shù)脂σmmax=70MPa,σmmin=42MPa,則
(2)當(dāng)碳纖維拉伸強(qiáng)度σf=3600MPa,碳纖維體積
分?jǐn)?shù)Vf=50%,CFRP筋公稱(chēng)直徑D=12mm時(shí),A取最小值:
依據(jù)典型因子對(duì)CFRP筋拉伸強(qiáng)度的影響權(quán)重研究,對(duì)各因子影響權(quán)重指標(biāo)進(jìn)行綜合評(píng)價(jià)。
圖1 CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型幾種典型因子影響權(quán)重Fig.1 Weight of influence for some typical factors in the tensile strength prediction model of CFRP bars
圖2收集了國(guó)內(nèi)外文獻(xiàn)報(bào)道中涉及實(shí)驗(yàn)室制備研究及工程化規(guī)模生產(chǎn)的大量CFRP筋實(shí)測(cè)性能參數(shù)[7-40],對(duì)預(yù)測(cè)模型中典型因子影響材料強(qiáng)度權(quán)重進(jìn)行大數(shù)據(jù)分析評(píng)價(jià)。
圖2 文獻(xiàn)報(bào)道CFRP筋性能指標(biāo)[7-40]Fig.2 Properties of CFRP bars in the literatures[7-40]
定義ψ為CFRP筋拉伸強(qiáng)度分布率,即在一定拉伸強(qiáng)度范圍內(nèi)出現(xiàn)樣本數(shù)占總樣本數(shù)的概率,則
(8)
其中N為總樣本數(shù),n為在確定范圍內(nèi)出現(xiàn)樣本數(shù)。
以CFRP筋拉伸強(qiáng)度σ≤1500MPa定義為Ⅰ級(jí)范圍;1500MPa<σ≤2500MPa為Ⅱ級(jí);σ>2500MPa為Ⅲ級(jí),圍繞圖2數(shù)據(jù),分別計(jì)算不同范圍CFRP筋拉伸強(qiáng)度分布率,主要規(guī)律如圖3所示。
圖3 CFRP筋拉伸強(qiáng)度分布規(guī)律Fig.3 Distribution of the tensile strength for CFRP bars
圖3結(jié)果較清晰地顯示,碳纖維拉伸強(qiáng)度σf及體積分?jǐn)?shù)Vf指標(biāo)對(duì)CFRP筋拉伸強(qiáng)度影響最為顯著,基本決定了CFRP筋的拉伸強(qiáng)度范圍。其中,Ⅰ級(jí)(σ≤1500MPa)強(qiáng)度范圍的CFRP筋,分布律相對(duì)較低,主要為碳纖維拉伸強(qiáng)度3600MPa,纖維體積分?jǐn)?shù)55%的CFRP筋;Ⅲ級(jí)(σ>2500MPa)強(qiáng)度范圍的CFRP筋,分布律最低,主要為碳纖維拉伸強(qiáng)度4900MPa,體積分?jǐn)?shù)60%~70%,公稱(chēng)直徑10mm以下的CFRP筋;Ⅱ級(jí)(1500MPa<σ≤2500MPa)強(qiáng)度范圍的CFRP筋,其碳纖維強(qiáng)度、體積分?jǐn)?shù)及公稱(chēng)直徑指標(biāo)一定范圍內(nèi)有較大可選性,影響Ⅱ級(jí)CFRP筋強(qiáng)度分布率顯著高于其他兩級(jí)。
表1 不同公稱(chēng)直徑CFRP筋拉伸強(qiáng)度的差異Table 1 Difference of tensile strength of CFRP bars with different nominal diameters
綜合CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型,以及典型因子對(duì)CFRP筋拉伸強(qiáng)度影響權(quán)重規(guī)律研究,可以較清晰地形成一套CFRP筋制備過(guò)程強(qiáng)度補(bǔ)償機(jī)制,如圖4所示。
圖4 不同CFRP筋拉伸強(qiáng)度典型因子強(qiáng)度補(bǔ)償關(guān)系Fig.4 Intensity compensation relationship with some typical factors for the tensile strength of CFRP bars
圖4分類(lèi)整理了碳纖維強(qiáng)度、體積分?jǐn)?shù)、CFRP筋公稱(chēng)直徑(這里忽略樹(shù)脂拉伸強(qiáng)度)等典型參數(shù)設(shè)計(jì)匹配與CFRP筋宏觀拉伸強(qiáng)度的關(guān)聯(lián)關(guān)系(其中公稱(chēng)直徑對(duì)CFRP筋拉伸強(qiáng)度的折損影響限值由紅色線條進(jìn)行標(biāo)注)。不同級(jí)別的CFRP筋強(qiáng)度補(bǔ)償機(jī)制存在一定差別。
處于Ⅰ級(jí)強(qiáng)度范圍(σ≤1500MPa)的CFRP筋,使用碳纖維拉伸強(qiáng)度為3600MPa,纖維體積分?jǐn)?shù)55%以下。改變公稱(chēng)直徑,CFRP筋拉伸強(qiáng)度一般不超過(guò)2500MPa,補(bǔ)償效果不明顯。
處于Ⅱ級(jí)強(qiáng)度范圍(1500MPa<σ≤2500MPa)的CFRP筋,碳纖維強(qiáng)度、體積分?jǐn)?shù)及公稱(chēng)直徑參數(shù)存在一定范圍的補(bǔ)償關(guān)系:(1)拉伸強(qiáng)度一定的碳纖維,體積分?jǐn)?shù)每增加5%,對(duì)應(yīng)CFRP筋拉伸強(qiáng)度增長(zhǎng)率約10%以上;(2)碳纖維體積分?jǐn)?shù)一定時(shí),可選用三類(lèi)不同強(qiáng)度碳纖維對(duì)材料的性能進(jìn)行補(bǔ)償,纖維強(qiáng)度每提升一級(jí),對(duì)應(yīng)CFRP筋拉伸強(qiáng)度增長(zhǎng)率約18%以上;(3)增大公稱(chēng)直徑,CFRP筋拉伸強(qiáng)度會(huì)有一定損失,影響程度由直徑折損系數(shù)B決定。受CFRP生產(chǎn)技術(shù)等條件影響,B值存在一定波動(dòng)。依據(jù)目前統(tǒng)計(jì)結(jié)果,公稱(chēng)直徑對(duì)CFRP筋拉伸強(qiáng)度的折損率約為10%左右。因此可以選用強(qiáng)度低、體積分?jǐn)?shù)大或強(qiáng)度高、體積分?jǐn)?shù)小的碳纖維原料對(duì)CFRP筋拉伸強(qiáng)度目標(biāo)值進(jìn)行設(shè)計(jì)匹配;在較大直徑CFRP筋拉伸強(qiáng)度設(shè)計(jì)中,須考慮大直徑對(duì)CFRP筋拉伸強(qiáng)度折損的影響,選擇碳纖維強(qiáng)度、體積分?jǐn)?shù)匹配目標(biāo)值應(yīng)高于設(shè)計(jì)值10%以上,從而綜合達(dá)到滿足性能要求且降低生產(chǎn)成本的效果。
處于Ⅲ級(jí)強(qiáng)度范圍(σ>2500MPa)的CFRP筋,使用碳纖維拉伸強(qiáng)度為4900MPa,體積分?jǐn)?shù)60%以上。根據(jù)補(bǔ)償機(jī)制,當(dāng)碳纖維拉伸強(qiáng)度為4200MPa時(shí),增加纖維體積含量達(dá)70%、公稱(chēng)直徑≤8mm時(shí),其拉伸強(qiáng)度也能達(dá)到2500MPa以上。
CFRP筋產(chǎn)品的組分參數(shù)預(yù)測(cè),基于碳纖維強(qiáng)度及體積分?jǐn)?shù)對(duì)CFRP筋拉伸強(qiáng)度的影響遠(yuǎn)大于其他因素的研究規(guī)律,已知CFRP筋拉伸強(qiáng)度、公稱(chēng)直徑及體密度,對(duì)照?qǐng)D4典型因子強(qiáng)度補(bǔ)償規(guī)律,可較方便地推測(cè)其組分碳纖維強(qiáng)度及體積分?jǐn)?shù)參數(shù)。
(1)CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型σ=0.95×[σfVf+σm(1-Vf)]-B×D綜合揭示了碳纖維及基體樹(shù)脂拉伸強(qiáng)度(σf,σm)、碳纖維體積分?jǐn)?shù)(Vf),以及CFRP筋公稱(chēng)直徑(D)等四種典型因素對(duì)材料宏觀拉伸強(qiáng)度的影響關(guān)系,對(duì)實(shí)際工程應(yīng)用具有較優(yōu)的適用性。
(2)CFRP筋拉伸強(qiáng)度預(yù)測(cè)模型中典型因子碳纖維拉伸強(qiáng)度(σf)和體積分?jǐn)?shù)(Vf)變化對(duì)材料宏觀拉伸強(qiáng)度影響最為重要(影響率為39.1%~46.7%和43.5%~52.6%),是決定CFRP筋拉伸強(qiáng)度的最重要因素。隨著公稱(chēng)直徑(D)增大,CFRP筋拉伸強(qiáng)度會(huì)有一定損失,影響率由直徑折損系數(shù)B決定,一般為7.1%~15.4%)?;w樹(shù)脂強(qiáng)度(σm)對(duì)CFRP筋的拉伸強(qiáng)度影響不明顯(影響率為0.3%~1.0%),相比其他三種影響因素,樹(shù)脂拉伸強(qiáng)度的影響可近似忽略。
(3)已知CFRP筋拉伸強(qiáng)度、公稱(chēng)直徑及體密度,對(duì)照預(yù)測(cè)模型典型因子強(qiáng)度補(bǔ)償規(guī)律,可較方便地推測(cè)其組分碳纖維強(qiáng)度及體積分?jǐn)?shù)參數(shù)。
[1] SMITH S J, BANK L C, GENTRY T R, et al. Analysis and testing of a prototype pultruded composite causeway structure[J]. Composite Structures, 2000, 49(2): 141-150.
[2] BANK L C, GENTRY T R, NUSS K H, et al. Construction of a pultruded composite structure: case study[J]. Journal of Composites for Construction, 2000, 4(3): 112-119.
[3] HARPER L T, TURNER T A, WARRIOR N A, et al. Characterisation of random carbon fiber composites from a directed fiber preforming process:the effect of tow filamentisation[J]. Composites:Part A, 2007, 38: 755-770.
[4] LI B, YANG Y X, YUE Q R, et al. Experimental study on mechanical properties of CFRP tendon[J]. Applied Mechanics and Materials, 2013, 357/360: 1097-1101.
[5] 黎偉捷, 李彪, 楊勇新, 等. 我國(guó)FRP筋產(chǎn)品標(biāo)準(zhǔn)及指標(biāo)的探討[J].玻璃鋼/復(fù)合材料, 2014(8): 101-104.
LI W J, LI B, YANG Y X, et al. Discussion on the Chinese standard and specifications of FRP bar products[J]. Fiber Reinforced Plastics/Composites,2014(8):101-104.
[6] 王彬, 楊勇新, 岳清瑞, 等. 復(fù)合理論預(yù)測(cè)國(guó)產(chǎn)碳纖維復(fù)合材料筋拉伸強(qiáng)度的離散性研究[J]. 玻璃鋼/復(fù)合材料, 2014(12): 63-67.
WANG B, YANG Y X, YUE Q R, et al. The discrete research on the values predicted by composite theories and measured for carbon fiber reinforced composite rods[J]. Fiber Reinforced Plastics/Composites, 2014(12): 63-67.
[7] 程?hào)|輝, 鄭文忠. 無(wú)粘結(jié)部分預(yù)應(yīng)力纖維聚合物筋混凝土梁試驗(yàn)[J]. 沈陽(yáng)建筑大學(xué)學(xué)報(bào) (自然科學(xué)版), 2008, 24(4): 537-542.
CHENG D H, ZHENG W Z. Behavioral research concrete beam prestressed with unbonded[J].Journal of Shenyang Jianzhu University(Natural Science), 2008, 24(4): 537-542.
[8] 郁步軍, 蔡文華, 張繼文, 等. 碳纖維增強(qiáng)復(fù)合材料筋黏結(jié)型群錨靜載試驗(yàn)研究[J]. 工業(yè)建筑, 2013, 43(4): 118-121.
YU B J, CAI W H, ZHANG J W, et al. Study on static load tests of bond type anchors for CFRP tendons[J]. Industrial Construction, 2013, 43(4): 118-121.
[9] 孟履祥, 關(guān)建光, 徐福泉. 碳纖維筋 (CFRP筋) 錨具研制及力學(xué)性能試驗(yàn)研究[J]. 施工技術(shù), 2005, 34(7): 42-45.
MENG L X, GUAN J G, XU F Q. The anchorage development and experiment study on the mechanical properties for CFRP tendons[J]. Construction Technology, 2005, 34(7): 42-45.
[10] 詹界東, 杜修力, 王作虎. 預(yù)應(yīng)力 CFRP 筋?yuàn)A片-粘結(jié)型錨具的試驗(yàn)[J]. 沈陽(yáng)建筑大學(xué)學(xué)報(bào)(自然科學(xué)版), 2010, 26(1): 31-36.
ZHAN J D, DU X L, WANG Z H. Experimental study on the wedge-bond anchorage of CFRP tendons[J]. Journal of Shenyang Jianzhu University(Natural Science), 2010, 26(1): 31-36.
[11] 方志, 梁棟, 蔣田勇. 不同粘結(jié)介質(zhì)中 CFRP 筋錨固性能的試驗(yàn)研究[J]. 土木工程學(xué)報(bào), 2006, 39(6): 47-51.
FANG Z, LIANG D, JIANG T Y. Experimental investigation on the anchorage performance of CFRP tendon in different bond mediums[J]. China Civil Engineering Journal, 2006, 39(6): 47-51.
[12] 方志, 蔣田勇, 梁棟. CFRP 筋在活性粉末混凝土中的錨固性能[J]. 湖南大學(xué)學(xué)報(bào)(自然科學(xué)版), 2007, 34(7): 1-5.
FANG Z, JIANG T Y, LIANG D. The anchorage behavior of CFRP tendons in RPC[J]. Journal of Hunan University(Natural Sciences), 2007, 34(7): 1-5.
[13] 李俊波. 配置體外CFRP預(yù)應(yīng)力筋混凝土梁抗彎性能的試驗(yàn)研究[D]. 長(zhǎng)沙:湖南大學(xué), 2005.
LI J B. Experimental study on flexural behavior of concrete beam prestressed with external CFRP tendons[D]. Changsha:Hunan University, 2005.
[14] 張繼文, 龔永智. CFRP 筋增強(qiáng)混凝土柱受力性能的研究[C]∥第五屆全國(guó) FRP 學(xué)術(shù)交流會(huì)論文集.北京:土木工程學(xué)報(bào),2007:495-504.
ZHANG J W, GONG Y Z. Study on the behavior of concrete columns reinforced with CFRP tendons[C]∥Proceedings of the 5th National FRP Symposium Conference. Beijing:China Civil Engineering Journal, 2007:495-504.
[15] 徐平, 丁亞紅, 曾憲桃, 等. 預(yù)應(yīng)力CFRP筋粘結(jié)夾片式球面錨具的研制與試驗(yàn)[J]. 玻璃鋼/復(fù)合材料, 2011(2): 3-7.
XU P, DING Y H, ZENG X T, et al. Experimental study and development on the CFRP tendons bonding spherical jaw vice anchorage[J]. Fiber Reinforced Plastics/Composites, 2011(2): 3-7.
[16] CHOI H T, WEST J S, SOUDKI K A. Effect of partial unbonding on prestressed near-surface-mounted CFRP-strengthened concrete T-beams[J]. Journal of Composites for Construction, 2010, 15(1): 93-102.
[17] CHOI H T, WEST J S, SOUDKI K A. Partially bonded near-surface-mounted CFRP bars for strengthened concrete T-beams[J]. Construction and Building Materials, 2011, 25(5): 2441-2449.
[18] GRANCE N, ENOMOTO T, BAAH P, et al. Flexural behavior of CFRP precast prestressed decked bulb T-beams[J]. Journal of Composites for Construction, 2011, 16(3): 225-234.
[19] RAFI M M, NADJAI A, ALI F, et al. Aspects of behaviour of CFRP reinforced concrete beams in bending[J]. Construction and Building Materials, 2008, 22(3): 277-285.
[20] DAVALOS J F, CHEN Y, RAY I. Effect of FRP bar degradation on interface bond with high strength concrete[J]. Cement and Concrete Composites, 2008, 30(8): 722-730.
[21] VOGEL H, SVECOVA D. Thermal compatibility and bond strength of FRP reinforcement in prestressed concrete applications[J]. Journal of Composites for Construction, 2007, 11(5): 459-468.
[22] DAVOUDI S, VOGEL H, SVECOVA D, et al. CFRP prestressed high-strength concrete prisms subjected to direct tension[J]. Journal of Composites for Construction, 2008, 12(6): 588-595.
[23] AHMAD F S, FORET G, Le ROY R. Bond between carbon fibre-reinforced polymer (CFRP) bars and ultra high performance fibre reinforced concrete (UHPFRC): experimental study[J]. Construction and Building Materials, 2011, 25(2): 479-485.
[24] MOON D Y, SIM J, OH H. Detailing considerations on RC beams strengthened with CFRP bars embedded in mortar overlay[J]. Construction and Building Materials, 2007, 21(8): 1636-1646.
[25] HA G J, KIM Y Y, CHO C G. Groove and embedding techniques using CFRP trapezoidal bars for strengthening of concrete structures[J]. Engineering Structures, 2008,30(4): 1067-1078.
[26] LORENZIS L D, SCIALPI V, TEGOLA A L. Analytical and experimental study on bonded-in CFRP bars in glulam timber[J]. Composites Part B: Engineering, 2005, 36(4): 279-289.
[27] HA G J, CHO C G, KANG H W, et al. Seismic improvement of RC beam-column joints using hexagonal CFRP bars combined with CFRP sheets[J]. Composite Structures, 2013, 95: 464-470.
[28] WAHAB N, SOUDKI K A, TOPPER T. Mechanism of bond behavior of concrete beams strengthened with near-surface-mounted CFRP rods[J]. Journal of Composites for Construction, 2010, 15(1): 85-92.
[29] ELREFAI A, WEST J, SOUDKI K. Fatigue of reinforced concrete beams strengthened with externally post-tensioned CFRP tendons[J]. Construction and Building Materials, 2012, 29: 246-256.
[30] TANARSLAN H M. The effects of NSM CFRP reinforcements for improving the shear capacity of RC beams[J]. Construction and Building Materials, 2011, 25(5): 2663-2673.
[31] NOVIDIS D G, PANTAZOPOULOU S J. Bond tests of short NSM-FRP and steel bar anchorages[J]. Journal of Composites for Construction, 2008, 12(3): 323-333.
[32] ANWARUL ISLAM A K M. Effective methods of using CFRP bars in shear strengthening of concrete girders[J]. Engineering Structures, 2009, 31(3): 709-714.
[33] WON J P, PARK C G, KIM H H, et al. Effect of fibers on the bonds between FRP reinforcing bars and high-strength concrete[J]. Composites Part B: Engineering, 2008, 39(5): 747-755.
[34] SASMAL S, KHATRI C P, RAMANJANEYULU K, et al. Numerical evaluation of bond-slip relations for near-surface mounted carbon fiber bars embedded in concrete[J]. Construction and Building Materials, 2013, 40: 1097-1109.
[35] ELBADRY M, ELZAROUG O. Control of cracking due to temperature in structural concrete reinforced with CFRP bars[J]. Composite structures, 2004, 64(1): 37-45.
[36] MALVAR L J, COX J V, COCHRAN K B. Bond between carbon fiber reinforced polymer bars and concrete. I: experimental study[J]. Journal of composites for construction, 2003, 7(2): 154-163.
[37] FLAGA K. Advances in materials applied in civil engineering[J]. Journal of Materials Processing Technology, 2000, 106(1): 173-183.
[38] SHARBATDAR M K, SAATCIOGLU M, BENMOKRANE B. Seismic flexural behavior of concrete connections reinforced with CFRP bars and grids[J]. Composite Structures, 2011, 93(10): 2439-2449.
[39] BOUGUERRA K, AHMED E A, EL GAMAL S, et al. Testing of full-scale concrete bridge deck slabs reinforced with fiber-reinforced polymer (FRP) bars[J]. Construction and Building Materials, 2011, 25(10): 3956-3965.
[40] WANG Y C, KODUR V. Variation of strength and stiffness of fibre reinforced polymer reinforcing bars with temperature[J]. Cement and Concrete Composites, 2005, 27(9): 864-874.
(本文責(zé)編:解 宏)
Evaluation and Application of Tensile Strength Prediction for CFRP Bars
WANG Bin,YANG Yong-xin,YUE Qing-rui,ZENG Bin
(Central Research Institute of Building and Construction Co.,Ltd.,Beijing 100088,China)
10.11868/j.issn.1001-4381.2015.001435
TQ327.3
A
1001-4381(2017)10-0117-07
國(guó)家高技術(shù)研究發(fā)展計(jì)劃項(xiàng)目(2012AA03A204)
2015-11-24;
2016-04-07
王彬(1984-),女,工程師,博士,主要從事高性能纖維增強(qiáng)復(fù)合材料方向研究,聯(lián)系地址:北京市海淀區(qū)西土城路33號(hào)中冶建筑研究總院有限公司2#504檢測(cè)中心研發(fā)部(100088),E-mail:mccwangbin@126.com