大體積混凝土溫控計(jì)算書

-.z.大體積混凝土溫控計(jì)算書混凝土的絕熱升溫T(t)=(1-e-mt)式中：T(t)混凝土齡期為t時(shí)的絕熱溫升〔℃〕mc每m3混凝土膠凝材料用量，取415kg/m3Q膠凝材料水熱化總量，Q=kQ0Q0水泥水熱化總量377KJ/kg〔查建筑施工計(jì)算手冊(cè)〕C混凝土的比熱：取0.96KJ/〔kg.℃〕ρ混凝土的重力密度，取2400kg/m3m與水泥品種澆筑強(qiáng)度系有關(guān)的系數(shù)取0.3d-1(查建筑施工計(jì)算手冊(cè)〕t混凝土齡期〔d〕經(jīng)計(jì)算：Q=kQ0=(K1+K2-1)Q0=(0.955+0.928-1)*377=332.9KJ/kg齡期36912151821242730ma*T(1)℃35.2149.7555.7458.2259.2459.8459.8459.9159.9459.9559.96混凝土收縮變形的當(dāng)量溫度混凝土收縮的相對(duì)變形值計(jì)算εy〔t〕=εy0〔1-e-0.01t〕m1m2m3.....m11式中：εy〔t〕齡期為t時(shí)混凝土收縮引起的相對(duì)變形值εy0在標(biāo)準(zhǔn)試驗(yàn)狀態(tài)下混凝土最終收縮的相對(duì)變形值取3.24*10-4m1m2m3.....m11考慮各種非標(biāo)準(zhǔn)條件的修正系數(shù)m1=1.0m2=1.0m3=1.0m4=1.2m5=0.93m6=1.0m7=0.57m8=0.835m9=1.0m10=0.89m11=1.01m1m2m3.....m11=0.447-.z.齡期36912151821242730εy〔t〕0.4670.921.3591.7852.1982.5992.9873.3643.7294.08410-5混凝土收縮相對(duì)變形值的當(dāng)量溫度計(jì)算Ty(t)=εy(t)/α式中：Ty(t)齡期為t時(shí)，混凝土的收縮當(dāng)量溫度α混凝土的線膨脹系數(shù)，取1.0*10-5齡期36912151824242730Ty(t)0.4670.921.3591.7852.1982.5992.9873.3643.7294.084℃混凝土的彈性模量E(t)=βE0(1-e-φ)式中：E(t)混凝土齡期為t時(shí)，混凝土彈性模量〔N/mm2〕E0混凝土的彈性模量近似取標(biāo)準(zhǔn)條件下28d的彈性模量：C40E0=3.25*104N/mm2φ系數(shù)，近似取0.09β混凝土中摻和材料對(duì)彈性模量修正系數(shù)，β=1.005齡期3691215182142730dE(t)0.7731.3631.8132.1572.4192.6202.7732.8892.9793.047104N/mm2各齡期溫差、內(nèi)部溫差Tma*=Tj+ξ(t)T(t)式中：Tma*混凝土內(nèi)部的最高溫度Tj混凝土的澆筑溫度，因攪拌砼無降溫措施，取澆筑時(shí)的大氣平均溫度，取15℃T(t)在齡期t時(shí)混凝土的絕熱溫升ξ(t)在齡期t時(shí)的降溫系數(shù)齡期36912151821242730dT(t)35.2149.7555.7458.2259.2459.6659.8459.9159.9459.95℃ξ(t)0.490.460.380.290.210.150.120.080.050.04Tma*22.2527.8926.1821.8817.4413.9512.189.798.007.40℃5、外表溫度本工程擬采用的保溫措施是：砼外表覆蓋一層塑料薄膜及棉氈，棉氈厚度為15mm左右，薄膜厚度0.1mm左右。Tb(t)=Tq+h’(H-h’)△T(t)式中：Tb(t)齡期為t時(shí)，混凝土外表溫度Tq齡期為t時(shí)，大氣的平均溫度取15℃△T(t)齡期為t時(shí)，混凝土內(nèi)部最高溫度與外界氣溫之差H混凝土的計(jì)算厚度H=h+2h’=1.8+2*0.37=2.275h’混凝土的虛厚度h’=λ混凝土導(dǎo)熱系數(shù)：λ=2.33W/m.kβ混凝土模板及保溫層的傳熱系數(shù)δi各保溫層材料的導(dǎo)熱系數(shù)βα空氣層傳熱系數(shù)可取βα=23W/m2·kβ=h’==0.237m齡期36912151821242730dTma*22.2527.8926.1821.8817.4413.9512.189.798.007.40℃△T(t)17.2522.8921.1816.8812.448.957.184.7932.4℃Tb(t)11.4413.5412.9111.309.648.347.686.796.125.90℃砼養(yǎng)護(hù)時(shí)溫差齡期〔d〕Tma*〔℃〕Tb〔℃〕Tq〔℃〕Tma*-Tb〔℃〕Tma*-Tq〔℃〕322.2511.441510.816.44627.8913.541514.358.54926.1811.301513.277.911221.8811.301510.586.301517.449.64157.84.641813.958.34155.613.342112.187.68154.52.68249.796.791531.792786.12151.881.12307.45.90151.50.9計(jì)算結(jié)果說明：所有溫差均小于20℃保溫層撤除時(shí)溫差計(jì)算齡期36912151821242730dTq15151515151515151515℃Tb(t)11.4413.5412.9111.309.648.347.686.796.125.90℃Tma*22.2527.8926.1821.8817.4413.9512.189.798.007.40℃Ty(t)0.1670.921.3591.7