1、大體積混凝土測溫點布置原則: 一、大體積硅溫度的控制不僅要控制內表溫差 （指硅中心最高溫度與之相對應 的硅表面溫度之間的溫差）和表面溫差（指硅中心最高溫度相對應的表面溫度 與環境溫度之間的溫差），更要控制硅的綜合降溫差（指硅內部的平均降溫差） 和降溫速率（指硅中心溫度或表面溫度每天的降溫幅度）。二、硅的任一降溫差都可以分解為平均降溫差及非均勻降溫差，前者產生外約 束應力，是產生貫穿性裂縫的主要原因，后者引起自約束應力，主要引起表面 裂縫。非均勻降溫差主要是控制硅的內表溫差。規范規定大體積硅的內表溫差 應控制在25攝氏度，該控制值是比較嚴格的，根據我們的工程實踐，該值可根 據工程實際情況適當放寬

2、，這主要取決于硅的一些實際物理指標，如：不同齡 期的彈性模量、松弛系數和抗拉強度。因此，在大體積硅施工前，對溫度控制 指標進行一些理論計算，對施工大有指導意義。三、測溫點的平面布置原則：1）平面形狀中心；2）中心對應的側邊及容易散 發熱量的拐角處。3）主風向部位。總之測溫點的位置應選擇在溫度變化大，容 易散熱、受環境溫度影響大，絕熱溫升最大和產生收縮拉應力最大的地方。四、測溫點的豎向布置：一般每個平面位置設置一組 3個，分別布置在硅的上、 中、下位置，上下測點均位于硅表面 10厘米處，另外在空氣，保溫層中各埋設 1個測溫點測量環境溫度、保溫層內的溫度。大體積混凝土養護一般不少于 7d ,并根據

3、板中心混凝土溫度變化及同條件養 護的混凝土試塊強度確定養護周期。混凝土的養護應采用保溫，保濕及緩慢降 溫的技術措施，一般在澆筑在厚度大于 3m時，要求考慮在大體積混凝土內部 設置冷卻水循環降溫措施，設冷卻水管，并通過溫度檢測控制混凝土中心與表 面的溫度或混凝土內部與冷卻水的溫度控制在 25 C以內。五、降低水泥水化熱和變形(1)在厚大無筋的或少筋的大體積混凝土中，摻加總量不超過20%的大石塊，減少混凝土的用量，以達到降低水化熱和節省水泥的目的。(2)改善配筋。為了保證每個澆筑層上下均有溫度筋，可建議設計人員將分布筋做適當調整。溫度筋宜分布細密，一般用 力8鋼筋，雙向配筋，間距15 cm. 這樣

4、可以增強抵抗溫度應力的能力。六、其他方面(1)改善約束條件，削減溫度應力。采取分層或分塊澆筑大體積混凝土，合理 設置水平或垂直施工縫，或在適當的位置設置施工后澆帶，以放松約束程度， 減少每次澆筑長度的蓄熱量，防止水化熱的積聚，減少溫度應力。對大體積混 凝土基礎與厚大的混凝土墊層之間設置滑動層，如采用平面澆瀝青或鋪卷材。在垂直面、鍵梢部位設置緩沖層，如鋪設 3050 mm后瀝青木絲板或聚苯乙烯 泡沫塑料，以消除嵌固作用，釋放約束應力。(2)提高混凝土的極限拉伸強度。選擇良好繼配的粗骨料，嚴格控制含泥量， 加強混凝土的振搗，提高混凝土密實度和抗拉強度，減小收縮變形，保證施工 質量。采取二次投料法，

5、二次振搗法，澆筑后及時排除表面積水，加強早期養 護，提高混凝土早期或相應齡期的抗拉強度和彈性模量。在大體積混凝土的基 礎內設置必要的溫度配筋，在截面變形和轉折處，底、頂板與墻轉折處，孔洞 轉角及周邊，增加斜向構造配筋，以改善應力集中，防止裂縫出現。七、大體積混凝土的信息化施工大體積混凝土施工應加強測溫和溫度控制，實行信息化控制，隨時控制混凝土 內的溫度變化，以便及時調整保溫及養護措施，使混凝土的溫度梯度和濕度不 至過大，以有效控制裂縫的出現。7.1 溫度監測 為掌握基礎內部混凝土實際溫度變化情況，了解冷卻水管進出水溫度，對基礎 內外部以及進出水管進行測溫記錄，密切監視溫差波動，來指導混凝土的養

6、護 工作，并同時控制冷卻水流量以及流向。測溫設備可采用“大體積混凝土溫度微機自動測試儀”，溫度傳感器預先埋設 在測點位置上，基礎承臺測點位置分承臺內部、薄膜下溫度、室內室外溫度、 冷卻水管進、出水溫度設置。測點溫度、溫差以及環境溫度的數據與曲線用電 腦打印繪制。當混凝土內外溫差超過控制要求時，系統馬上報警。測溫點的布 置應考慮由于大體積混凝土澆筑順序時間不一致，應由各區域均勻布置，核心 區、中心區為重點。7.2 監測結果及其分析根據各測點所測溫度匯總混凝土溫度情況表，并繪制基礎混凝土升降溫曲線， 了解本工程大體積混凝土測溫情況和特點。根據一般 規律，大體積混凝土澆搗 結束后，在基礎的中心部位將

7、形成一高溫區，升溫時間為6070 h ,高溫持續時間較長，均在3040 h.混凝土的入模溫度較高，會加快水泥水化的進行，故 早期水化熱積聚上升，將造成混凝土的升溫速度加快。當混凝土保溫層揭除后， 混凝土表面溫度會明顯受晝夜大氣溫度的 影響，溫度下降。一般循環冷卻水帶 走的中心部位混凝土的熱量較四周表面和底部要多，因此，中心部位混凝土因 冷卻水所產生的降溫數值大，混凝土四周表面和底部所產生的降溫數值小。在 實際施工中可根據詳細測溫情況，進行分段 計算。7.3 大體積混凝土裂縫成因分析大體積混凝土施工易產生裂縫，產生裂縫有多方面原因，如約束情況，周圍環 境濕度，混凝土的均勻性，分段是否妥當，結構形

8、式等，都可能引起大體積混protecti ngfire contr olfacilities,firepr evention,reportsoffireelctivitiesinobeytheschoolrule s and regulati ons, on time, on time home toprevent accidents. 8,schoolto school inspe ctions ona reg ular ba sis,found hi dden in time,a nd i n sever ecase s,itis hardto eliminate immediatelyc

9、losed, andreportedtot he localpeople'sGovernment,educati on,a nd r uleoflaw section.9,t heschoolshould a lways check t he internalwall s,retaini ng wall s,ponds, raili ngs, handrails, doors, Windows,staircasesand avarietyofsports,extracurricular activities,facilitie ssuchasfire safety,i nfrastru

10、ct ure se curit y,unsafe facilitytoimmediatelyrepaira nd demolitionto ensure thatteachers a nd studentsw ork,lear n, live ve nues and facilities are safe andreliable. SongLi n Xiang LiuJiapingelementaryschoolMar ch 2016song Lin Xia ngLi uJiapi ng primarysch oolfiresafetysystemstoenhancefire safety,

11、protecti on of public property andthe life and propertysafety of teachers andstudents,schoolfiresafetyintoday-t o-daymanageme nt,is developing t hefollow ingfiresafetysystem.1,strengthe nfiresafetyeducation ofthewholeschool.According to therequirementsofthe FireServicesAct,sothateveryonehasofkee pin

12、g firecontr olsafety,In orderto ensure normalteaching orde r, prote cting st ude nts'healt hy growth, ensuring t hat national(property) isnot lost ,topra corre ctional ce ntre,a police station , atow nshippeopl e'sGovernme ntshall not concealt heaccident.4w eek,teachers are on.I - .I. . I. -

13、. . I _ I- cidents,foll ow the"preve ne thelea dershipvalues; stre ngthe nthe e- 一 1 - I _ osses" principl e,accordi ng to thelocalconditi ons, makethe management system.1,thepri ncpialis there sponsibility ofschool saschools toe nsure normalteaching or der;responsi ble forschool safetylea

14、dershipalway smaintaine d cl ose contact a nd districtpoli. . I . 一 . _ . I , 一 II I . . _ . I _L I 1_1.1I . ._LI . . 1 一 一 dershipofPre side ntse curityworklea dinggr oup.The head tea cherto thelea dership team isresponsi blefor,im plementati on ofthea ccountabilitysystem.2,schoolmont hlystude ntkn

15、owle dge about safetyeducati on,education should be diversified in theform every safetyeducationforst ude ntsofclasses perweekshould betargeted.Tocarry on emerge ncy issue s deali ngwith e ducation in Ge neral,self-hel pand mutual re scue knowledge. Emergencycalls (such as 110,119,122, 120, andsothe

16、poli cestationonschoolsafetyand help. 5,strengtheningteachers 'morale ducation,establi shadedi catedl ove, improvi ng educati on quality,observet he students' psychologicalchangesata nytime andtake preventive measures, no cor poral punishme ntand cov ert cor poral punishme ntonstudents, stud

17、ent outoftheclassroom, schools maynot be. 6, unit sor departments usestud entStreetpr opaganda or partici patein t hece lebrations,a swell as partici pating i nothersocialw- -_L_ . I. L . .< I 1_ |_ I. > I. .1. _ L _.一一 .一一 .一 |_| - I_ _LI_. > - 1 一 . . _|-一一. 一一 ”. .一 _. I 一一 l_. I I. I -

18、_L |_.一 . I I ,I 一 on) use commonse nsei neducati on.3,t heesta blishment ofmajora cci dent re porting sy stem.Schoolst udents reportmajor accident wit hina nhour ofeducati on;studentrun and disappearancestoreport; re portofthe accide nt to awrittenreportintriplicate,ork,wit houtapprovaloftheCorre c

19、tionalCe ntre,school principals consent,without organizati on. Wit houtthea pproval ofrelevantde partments,may organizest udentsto partici patein firefighting, disaster re liefand so on.7,schools should e ducate stude ntsto.I- Ld_L I-I 一 _. I L . I. IL . | _ _> .11. . |_ I _ 一 . _ I一.-. - _ II, L

20、 . 1 L . I _凝土的裂縫。就本工程的大體積混凝土而言，由于其截面尺寸較大，所以外荷載或次應力引起的裂縫可能性很小。但正由于結構截面大，水泥水化時所釋放的熱量就會產生較大的溫度變化和收縮作用，由此造成的溫度梯度收縮應力是導致大體積砼產生裂縫的主要原因。這種裂縫分為兩類：一、表面裂縫，大體積混凝土由于其內部與表面散熱速率不一樣，在其表面形成溫度梯度，從而表面產生拉應力，內部產生壓應力。而此時混凝土的齡期很短，抗拉強度很低，溫差產生的表面拉應力，超過此時的混凝土極限抗拉強度，就會在混凝土表面產生裂縫。此種裂縫一般出現在混凝土澆筑后的第34天里。二、貫穿裂縫，混凝土澆數天后，水化熱基本已釋放

21、，就開始進入降溫階段，由于逐漸降溫而產生收縮，再加上混凝土硬化過程中，由于混凝土內部拌合水的水化和蒸發以及膠質體的膠凝等作用，促使混凝土硬化時收縮。這兩種收縮由于受到基底或結構本身的約束，也會產生很大的拉應力，當此拉應力超過砼此時的抗拉強度，砼整個截面就可能產生貫穿裂縫，這種收縮裂縫才是危害最大的裂縫。7.4 大體積混凝土施工控制措施從控制裂縫的觀點看，表面裂縫危害小，但也會影響結構使用或外觀；而貫穿裂縫則要影響結構的整體性、耐久性和防水性，可能導致結構不能正常使用。為了防止溫度裂縫的出現或把溫度裂縫控制在某個界限內，就必須進行溫度控制。根據以往施工經驗和大體積砼的熱工計算，為了防止出現有害裂

22、縫，我們在馬鋼2#2500m高爐、熱風爐基礎施工中采用以下措施：采用低熱水泥一一礦渣水泥，降低水化溫升，強度富余大；優化配合比設計，在硅摻入一定比例的粉煤灰、高效緩凝減水劑和膨脹劑，以減少水泥用量，降低水化熱，并利用混凝土的60天強度；硅表面采取蒸氣保溫養護，縮小硅內外溫差。控制硅的入模溫度，進行斜面薄層連續澆筑； 電子測溫elctivitiesinobeytheschoolrule s and regulati ons, on time, on time home toprevent accidents. 8,schoolto school inspe ctions ona reg ular

23、 ba sis,found hi dden in time,a nd i n sever ecase s,itis hardto eliminate immediatelyclosed, andreportedtot he localpeople'sGovernment,educati on,a nd r uleoflaw section.9,t heschoolshould a lways check t he internalwall s,retaini ng wall s,ponds, raili ngs, handrails, doors, Windows,stair case

24、sand avarietyofsports,extracurricular activities,facilitie ssuchasfire safety,i nfrastruct ure se curit y,unsafe facilitytoimmediatelyrepaira nd demoliti onto ensure thatteachers a nd studentsw ork,lear n, live ve nues and facilities are safe andreliabl e. SongLi n Xiang LiuJiapingeleme ntaryschoolM

25、ar ch 2016song Lin Xia ngLi uJiapi ng primaryschoolfiresafety systemstoenhancefire safety, protecti on of public property andthe life and propertysafety of teachers andstudents,schoolfiresafetyintoday-t o-daymanageme nt,is developing t hefollow ingfiresafetysystem.1,strengthe nfiresafetyeducation of

26、thewholeschool.According to therequirementsofthe FireServi cesAct,sothateveryonehasofkee ping firecontr olsafety,In orderto ensure normalteaching orde r, prote cting st ude nts'healt hy growth, ensuring t hat national（property） isnot lost ,topra corre ctional ce ntre,a police station,a tow nship

27、peopl e'sGovernme ntshall not concealt heaccident.4w eek,teachers are on.I - .I. . I. -. . I _ I- cidents,foll ow the"preve nv e thelea dershipvalues; stre ngthe nthe e- 一 1 - I _ osses" principl e,accordi ng to thelocalconditi ons, makethe management system.1,thepri ncpialis there spo

28、nsibility ofschool safety,schoolse curity underthe lea dershipofPre side ntse curityworklea dinggr oup.The head tea cherto thelea dership team isresponsi blefor,im plementati on ofthea ccou ntabilitysystem. 2,schoolmont hlystude ntknowle dge about safetyeducati on,education should be diversified in

29、theform every safetyeducationforst ude ntsofclasses perweekshould betargeted.Tocarry on emerge ncy issue s deali ngwith e ducation in Ge neral,self-hel pand mutual re scue knowledge. Emergencycalls （such as 110,119,122, 120, andsoschools toe nsure normalteaching or der;responsi ble forschool safetyl

30、eadershipalway smaintaine d cl ose contact a nd districtpoli cestations, canvassingsupport fromthe poli cestationonschoolsafetyand help. 5,strengtheningteachers 'morale ducation,establi shadedi catedl ove, improvi ng educati on quality,observet he students' psychologicalchangesata nytime and

31、take preventive measures, no cor poral punishme ntand cov ert cor poral punishme ntonstudents, student outoftheclassroom, schools maynot be. 6, unit sor departments usestudentStreetpr opaganda or partici patein t hece lebrations,a swell as partici pating i nothersocialw. . I . 一 . _ . I , 一 II I . .

32、 _ . I _L I 1_1.1I . ._LI . . 1 一一 . 一 I 一 _L_ . I. L . .< I 1_ |_ I . >I. .1. _ L _.一 一 .一一 .一 |_| - I _ _LI _. > - 1 一 . . _|-一一. 一一 ”. .一 _. I 一一 l_. I . _ I - _|, |_ . 一 . I I , I .on） use commonse nsei neducati on.3,the esta blishment ofmajora cci dent re porting sy stem.Schoolst udent

33、s reportmajor accident wit hina nhour ofeducati on;studentrun and disappearancestoreport; re portofthe accide nt to awrittenreportintriplicate,ork,wit houtapprovaloftheCorre ctionalCe ntre,school principals consent,without organizati on. Wit houtthea pproval ofrelevantde partments,may organizest ude

34、ntsto partici patein firefighting, disaster re liefand so on.7,schools should e ducate stude ntsto.I- Ld_L I-I 一 _. I L . I. IL . | _ _> .11. . |_ I _ 一 . _ I一.-. - _ II, L . 1 L . I _7.4.1 合理選擇原材料石子選用531.5mm粒徑碎石，連續級配，含泥量不超過1%中砂（細度模數1.1.1 泥量不超過2%；桃沖水泥廠寨峰牌散裝32.5 號礦渣水泥；高效緩凝減水劑：1% （占水泥重）；膨脹劑JM-m： 81

35、0% II級粉煤灰1015%（占水泥重），原材料均須抽樣試驗。1.1.2 優化混凝土配合比設計為減少水泥用量, 降低水化熱, 減少混凝土收縮, 延緩混凝土初凝時間, 改善和易性 , 混凝土配制采用三摻技術（即混凝土中摻加粉煤灰、減水劑、膨脹劑）減水劑針對該工程的施工特點和正處于冬季的情況, 實驗室經過多次試配，最后選用的配合比為：水: 水泥 : 中砂 : 石子 : 粉煤灰 : 減水劑 : 膨脹劑=178:275:770:1120:40:3:26 。1.1.3 大體積混凝土保溫養護措施1.1.3.1 大體積混凝土的熱工計算1）混凝土內部最高絕熱升溫值：Th=WQ/Q ,本工程中采用32.5礦渣水

36、泥，C20混凝土。故Th=43.62）、混凝土中心最高溫度：Tm國T+Th*ET=10C （入模溫度），工散熱系數取0.8。Tma=44.9C。3）、混凝土表面溫度：Tb=Tq+4h （H-h） AT/H2Tq 為環境溫度取 5C, AT= TMA-Tq=39.9 C , H=2.57m, h=0.07m。故 Tb=9.2 C。4）、混凝土內表溫差： Tc= TMA-Tb=44.9- 9.2=35.7 C>25C顯然混凝土內表最大溫差超過規定要求值，若不采取措施，將必然會產生表面裂縫。1.1.3.2 混凝土表面保溫養護措施lectricity li nes,equi pmenti nsp

37、ecti ons,found hidden i n time for rectificati on,mai ntena nce, andse curity.9, do notuse an open flame in t he classr oom, pr ohi bitburni ng stove, lit ca ndle s, mosquit o repel lent, no sm oking, and ba nni ng messywiri ng. Without using any household a ppli ances is not allowed. 10, liveoncamp

38、usfaculty members, mustleadbyexample,andeducatefamiliesandchildrenreadytofire.11,householduseofgasinschools,tomasterproperusage,payattenti ontot he leak -proof,explosi on-pr oof, fireproof,closi ngvalve afterusetoensuresecurity.12,diningroommustbe qualified,and annual te sting ofpre ssure vessel s,t

39、o reg ularlyche ck,the cantee nw orkersmust be certifie d,strictly by operation operation,gastankand st ovesafety dista nceof1.5meters,topreventaccidents. 13,the adverse conse quences ca used byig nori ng firesafety regulations,willbepunishe d,untilinvestigatedforlegalresponsibility.S ong Lin Xiang

40、Liu Jia ping elementaryschool March2016 Xia ng Liu Jia pi ngelementary school, pi ne sl opessurroundi ngsafety manageme ntsystem 1 teachers a nd st udents,t hesurroundi ng area oftheschoolgovernancecovers personal a ndfood hygie ne, culturalev entsand ot heraspe cts,integratedg overna nce shall obta

41、i nwide supportand f ullcooperation ofthecommunit y.On the surroundinge nvironmentin schools shouldbecl osely monitore d.2,schoolw ork at the sametime,shoul d payattenti on to t hesaf etymanagementofschoolenvironment,shoul d takethe i nitiativeto conta ctthe district police station,thevillageCommitt

42、ee,Corre ctionalCe ntre,T ownship g overnme nt,busine ss managementand ot herde partmentsto do ag ood jobmanageme nt. 3,tea cher ondutywith t heexce ption ofinspe ctionsinschool s,should al so payattenti ontoenvironmentali nspecti onsnearthecampus,foundthatthejoblessmigrants fromruralareas,forexampl

43、e,harassme ntofstudents a nd avariety ofacci dent s,accor dingto different situati ons reporte d schoolofficial sor the police stati on i n atimely manne r,topr otectthesafety ofstudents.4,everydaybeforeschool,teachersremindstudents,payatte ntiont otrafficsafety. 5,should educatestudentstorespectsoc

44、ial ethics,andvarious regulations,maintaining public order,and fightthebadguys,andgraspthecorrectwaysand meansofmaintaining and improvi ng student s'self-care a bilit y.6,theestabli shment ofemergency rescueteamsofteachers inschools,onhighalertanddeployed.SongLinXia ng Li uJiapinge lementary sch

45、oolMarch2016song Lin Xiang LiuJiapi ng primaryschoolteachersandstudentsorganizationsoutofsafetymanagement systemorganizationactivitiesbetweenteachersandstudents,todrawupa preci se pla nand se curitymeasures mustbesignedbytheschoolofficial s to reviewthe programme of activitiesagreeduponCorrectionalC

46、enteragreed toimpl ement. Organizati ontothe field relatively faror activities requireapprovalbytheDeputyDirector ofthe Educati on Burea u inchargeofse curit y. 2,ea ch a ctivityshoul dhave aspe cificresponsi bility, payattention tothepersonsage, physicalmatch.Route 3,a ctivities, l ocati on, fiel d

47、 survey sshoul d be carried out ina dvance. 4,activitiesforthe meansoftransportshoul d explai nthe sit uationtothe schoolto complywith vehicle,safetyrequirements,before the neforrepair s.5,ea cha ctivitymusthave security,emergencyresponse plan foraccidents. 6,pi cni cs, hiking, picnict o payattentio

48、n to fireprevention,food poisoning,prevention offallaccidents7,t he activitie s nearthe rivers, reservoirs,no measuresor donot meet these curity re quireme ntsofthe Organization andnot let students intothe waterelctivitiesinobeytheschoolrule s and regulati ons, on time, on time home toprevent accide

49、nts. 8,schoolto school inspe ctions ona reg ular ba sis,found hi dden in time,a nd i n sever ecase s,itis hardto eliminate immediatelyclosed, andreportedtot he localpeople'sGovernment,educati on,a nd r uleoflaw section.9,t heschoolshould a lways check t he internalwall s,retaini ng wall s,ponds,

50、 raili ngs, handrails, doors, Windows,stair casesand avarietyofsports,extracurricular activities,facilitie ssuchasfire safety,i nfrastruct ure se curit y,unsafe facilitytoimmediatelyrepaira nd demoliti onto ensure thatteachers a nd studentsw ork,lear n, live ve nues and facilities are safe andreliab

51、l e. SongLi n Xiang LiuJiapingeleme ntaryschoolMar ch 2016song Lin Xia ngLi uJiapi ng primarysch oolfiresafetysystemstoenhancefire safety, protecti on of public property andthe life and propertysafety of teachers andstudents,schoolfiresafetyintoday-t o-daymanageme nt,is developing t hefollow ingfire

52、safetysystem.1,strengthe nfiresafetyeducation ofthewholeschool.According to therequirementsofthe FireServi cesAct,sothateveryonehasofkee ping firecontr olsafety,In orderto ensure normalteaching orde r, prote cting st ude nts'healt hy growth, ensuring t hat national(property) isnot lost ,topra co

53、rre ctional ce ntre,a police station , atow nshippeopl e'sGovernme ntshall not concealt heaccident.4w eek,teachers are on.I - .I. . I. -. . I _ I- cidents,foll ow the"preve ne thelea dershipvalues; stre ngthe nthe e- 一 1 - I _ osses" principl e,accordi ng to thelocalconditi ons, maketh

54、e management system.1,thepri ncpialis there sponsibility ofschool saschools toe nsure normalteaching or der;responsi ble forschool safetyleadershipalway smaintaine d cl ose contact a nd districtpoli. . I . 一 . _ . I , 一 II I . . _ . I _L I 1_1.1I . ._LI . . 1 一 一 dershipofPre side ntse curityworklea

55、 dinggr oup.The head tea cherto thelea dership team isresponsi blefor,im plementati on ofthea ccountabilitysystem.2,schoolmont hlystude ntknowle dge about safetyeducati on,education should be diversified in theform every safetyeducationforst ude ntsofclasses perweekshould betargeted.Tocarry on emerg

56、e ncy issue s deali ngwith e ducation in Ge neral,self-hel pand mutual re scue knowledge. Emergencycalls (such as 110,119,122, 120, andsothepoli cestationonschoolsafetyand help. 5,strengtheningteachers 'morale ducation,establi shadedi catedl ove, improvi ng educati on quality,observet he students' psychologicalchangesata nytime andtake preventive measures, no cor poral punishme ntand cov ert cor poral punishme ntonstudents,