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3c3t - 2008/7/21 22:44:00
c20c30c40混凝土配合比设计计算步骤Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

C20混凝土配合比初步计算Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
设计步骤:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(一)设计初步配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、确定混凝土配制强度fcu,o=1.645×5+20=28.2MPaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、计算水灰比(w/cÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
w/c=aa×fce/fcu,o+ aa×ab×fceÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
=0.46×32.5×1.13/28.2+0.46×0.07×32.5×1.13Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
=0.57Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3、选定单位用水量(MwoÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
由于碎石最大粒径31.5mm,选用混凝土用水量:Mwo=180Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
4、计算单位用灰量(McoÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1)按强度计算单位用灰量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mco= Mwo/ w/c=180/0.57=316Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
5、选择砂率(βsÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
胜根据碎石最大粒径31.5mm及水灰比w/c=0.57,选定混凝土砂率取βs=34%Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
6、计算砂石用量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1)采用质量法Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
已知:单位用灰量Mwo=180 Kg/m3,砂率βs=34%Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mso+Mgo=PcpMcoMwoÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mso/Mso+Mgo=0.34Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
假设混凝土混合料湿表观密度Pcp=2400 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mso+Mgo=2400-316-180Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mso/Mso+Mgo=0.34Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
解得砂用量Mso=647Kg/m3,碎石用量Mgo=1257Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Mco : Mwo : Mso : Mgo =316: 180 : 647 : 1257Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1 : 0.57 : 2.05 : 3.98 w/c=0.57Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3c3t - 2008/7/21 22:46:00
原始资料:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、混凝土设计强度等级为C30(空心板)无强度历史统计资料,桥梁所在地区属寒区。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、组成材料:PO42.5等级牡丹江牌水泥,密度PC=3.1×103Kg/m3,富裕系数=1.13,砂为中砂表观密度P'S=2.65×103Kg/m3,碎石最大粒径dmax=40mm,表观密度P'g=2.75×103Kg/m3,水为一般饮用水。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
设计步骤:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(一)设计初步配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、确定混凝土配制强度(Ryp=Ry+1.65б=30+1.645×5=38.2MPaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、计算水灰比(w/c)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(1)按强度要求计算水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
           Rs=RCRb=1.13×42.5=48MPaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(2)计算混凝土水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
w/c=ARs/Ryp+ABRs=0.48×48/38.2+0.48×0.52×48=23/50.1=0.46Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(3)按耐久性校核水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
    根据混凝土所处环境属于寒区允许最大水灰比为0.55.按强度计算水灰比是0.46。符合耐久性要求,采用计算水灰比0.46。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3、选定单位用不水量(Mwo)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
   由于碎石最大粒径40mm,选用混凝土用水量:Mwo=175Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
4、计算单位用灰量(Mco)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(1)按强度计算单位用灰量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
      Mco= Mwo/ w/c=175/0.46=380 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(2)按耐久性校核单位用灰量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据混凝土所处环境属寒区配筋混凝土,最小水泥用量不低于300 Kg/m3,按强度计算单位用灰量380 Kg/m3,符合耐久性要求,采用单位用灰量为380 Kg/m3。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
5、选择砂率(βs)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
胜根据碎石最大粒径40    mm及水灰比w/c=0.46,选定混凝土砂率取βs=32%。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
6、计算砂石用量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(1)采用质量法Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
已知:单位用灰量Mwo=175 Kg/m3,砂率βs=33%Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
      Mso+Mgo=Pcp-Mco-MwoÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
      Mso/Mso+Mgo=0.33Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
假设混凝土混合料湿表观密度Pcp=2400 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
     Mso+Mgo=2400-380-175Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
     Mso/Mso+Mgo=0.33Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
解得砂用量Mso=609 Kg/m3,碎石用量Mgo=1236 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
按质量法计算初步配合比:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
     Mco : Mwo : Mso : Mgo =380 : 175 : 609 : 1236Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
即:  1 : 0.46 : 1.6 : 3.25 w/c=0.46Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(二)试拌混凝土,提出基准配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、按计算初步配合比试拌15L混凝土拌后物,测定其坍落度为2.5cm,满足施工和易性要求,其粘聚性和保水性亦良好。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、提出基准配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
   Mca :Msa :Mga=1 :1.6 : 3.25, w/c=0.46Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(三)检验强度,测定试验室配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、检验强度Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
采用水灰比分别为(w/c)A=0.41  B=0.46  C=0.51拌制三组混凝土拌和物。砂、碎石用量不变,用水量亦保持不变。三组配合比经拌制成型,在标准条件养护28d后,A组抗压强度为41.5MPa,B组抗压强度为34.0MPa,C组抗压强度为28.5MPa。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
绘制混凝土配制强度Ryp=38.2MPa的灰水比c/w2.38关系曲线即水灰比w/c=0.42Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、确定试验室配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
        Msb+Mgb=2400-417-175Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
        Msb/ Msb+ Mgb=0.33Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
即Msb=596,Mgb=1213Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
修正后配合比Mcb:Msb:Mgb=417:596:1213=1:1.43:2.91Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水灰比Mwb/Mcb=175/417=0.42Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
计算湿表观密度Pcp=417+175+596+1213=2401 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
实测湿表观密度P'cp=2400 Kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
修正系数б=2400/2401=1Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
因此试验室配合比为Mcb':Msb':Mgb'=1:1.43:2.91, w/c=0.42Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3c3t - 2008/7/21 22:47:00

C40混凝土配合比设计Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

C40混凝土用于某公路K**+***桥钢筋混凝土施工,要求施工时现场坍落度为30~50mm,碎石的最大粒经为30mm。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
材料选择Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水泥:采用牡丹江产P.O42.5普通硅酸盐水泥。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
砂:产地岔林河,细度模数2.62属于中砂,颗粒级配属 Ⅱ区。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石:产地冷山,规格分别为16~31.5cm、4.75~16cm,压碎值、含泥量等指标也均符合规范求。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
粗集料配合比设计Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据筛分结果粗集料的掺配比例为: 4.75~16cm cm碎石为35%Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
16~31.5cm cm碎石为65%。
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
  按照上述比例掺配两种集料,经几次筛分试验,其结果均满足4.75~31.5cm碎石连续级配.Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
配合比设计Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、计算初步配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1)确定混凝土配制强度(fcu,o)。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
混凝土设计强度fcu,k=40MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
标准差σ=5.0 Mpa
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
则混凝土配制强度:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
fcu,o= fcu,k+1.645×σ=48.2 MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2)计算水灰比(W/C)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(1)按强度要求计算水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
①计算水泥实际强度Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
采用42.5普通硅酸盐水泥fce,k=42.5Mpa,富余系数γc=1.13Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
则水泥实际强度为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
fce=fce,k
×γc =48.0MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
计算水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石 A=0.48Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
B=0.52
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
W/C=A×fce/(fcu,o+A ×B ×f ce)=0.45Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(2)按耐久性校核水灰比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据桥梁施工规范要求:严寒地区受严重冰冻,水流侵蚀最大水灰比不得大于0.65。按照强度计算的水灰比符合耐久性要求,故采用0.45。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(3)确定单位用水量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据要求,混凝土拌和物的坍落度为30~50mm,碎石的最大粒径为30mm。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
确定混凝土的单位用水量为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mwo=185kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(4)计算单位水泥用量(mco)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
①按强度计算单位用灰量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
已知混凝土单位用水量为Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mwo=185kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水灰比W/C=0.45
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
则计算单位混凝土用灰量:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mco=mwo×c/w=411kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
②按耐久性校核单位用灰量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据桥梁施工技术规范要求:严寒地区受严重冰冻,水流侵蚀作用且有钢筋,混凝土最小水泥用量为300 kg/m3 。按强度计算的单位用灰符合耐久性要求,故采用mco=411kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(5) 确定砂率(SP)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据碎石的最大粒径为30mm,且水灰比为0.45 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
选定混凝土砂率为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
SP=33%Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(6)计算粗,细集料单位用量(mgo , mso)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
假定混凝土毛体积密度为2400 kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
185+411+ mgo+ mso=2400 ¨¨¨¨¨①Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mso×100/(mso+mgo) =33%¨¨¨¨¨②Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
解式①、②得:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mso=595 kg/m3
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mgo=1209kg/m3
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
则混凝土初步配合比为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mco: mso: mgo=1:1.45:2.94
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
W/C=0.45
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、试拌调整,提出基准配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1)计算试拌材料用量Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
按计算初步配合比试拌15L混凝土拌和物,各种材料用量:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水泥:411×0.015=6.165kgÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水:185×0.015=2.775kgÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
砂:595×0.015=8.925kgÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石: 1209×0.015=18.135kgÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2)调整工作性,提出基准配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
按照计算材料用量拌制混凝土拌和物,测定其坍落度为40mm,而且拌和物的粘和性和饱水Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
性良好,满足施工和易性要求,因此提出基准配合比为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mco: mso: mgo=1:1.45:2.94 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
W/C=0.45Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3、检验强度Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
  1)、采用水灰比分别为0.43,0.45,0.47 拌制三组混凝土拌和物,拌制时用水量不变,水泥用量分别为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
430 kg/m3 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
411 kg/m3 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
394 kg/m3
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2 8
天后抗压强度分别见下表:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水灰比:0.43Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
试件编号

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

1Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

23456
抗压强度

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

51.5Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

52.0Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

52.1Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

53.5Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

52.6Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

51.8Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

平均值

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

52.3MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水灰比:0.45Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
试件编号

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

1Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

23456
抗压强度

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

49.2Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

49.5Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

47.9Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

48.5Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

48.3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

47.2Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

平均值

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

48.4MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水灰比:0.47Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
试件编号

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

1Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

23456
抗压强度

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

45.3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

43.2Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

45.5Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

44.7Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

43.8Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

44.2Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

平均值

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

44.5MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:

Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
  2)、绘制灰水比和强度曲线:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
强度(Mpa)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
灰水比    ( 略 )Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
由混凝土强度与灰水比关系曲线关系可知,与试配混凝土强度38.2Mpa的灰水比值为2.22即水灰比为0.45。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
4、确定试验室配合比Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1)强度修正Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据强度、灰水比关系曲线,按强度修正后混凝土各材料用量为:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
用水量mwb=185kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水泥用量 mcb =411kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
砂用量msb =595kg/m3 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石用量 mgb =1209kg/m3 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
实测混凝土拌和物的毛体积密度为ρh=2470kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
校正系数K=2470/2400=1.03Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
修正后混凝土各材料用量为Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水185×1.03=190kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水泥411×1.03=423kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
砂595×1.03=612kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石1209×1.03=1244kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
则试验室配合比为mcb:msb:mgb=1:1.45:2.94Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
W/C=0.45Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
根据试验室配合比拌制12组抗压试件,标准养护28天后抗压强度见下表:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
试件编号123456
抗压强度Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(Mpa)
48.549.248.749.247.945.9
试件编号789101112
抗压强度Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(Mpa)
48.948.051.752.449.248.7
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2)
、强度评定Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1、计算实测强度的平均值(mfcu)及标准差(sfcu)Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
标准差sfcu=1.68Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
平均值mfcu=49.0MpaÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
2、根据试件组数(N=12)判定合格系数Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
λ1=1.70 Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
λ2=0.9
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3
、强度评定Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(1)mfcu-λ1sfcu≥0.9fcu.kÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
49.0-1.7×1.68=46.1Mpa>0.9×40=36.0Mpa   合格Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
(2)fcu.min≥λ2fcu.kÑ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
45.9Mpa≥0.9×40=36.0Mpa   合格Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
故该12组混凝土试件块强度评定合格Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
上述式中:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
sfcu
————混凝土强度标准差Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mfcu————混凝土强度平均值Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
fcu.k————混凝土设计强度值Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
fcu.min————混凝土强度的最小值Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
λ1 . λ2————评定合格系数.查表得出Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
5
、结论:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
经过理论推算和试验室结果,确定最终配合比:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
mcb:msb:mgb=1:1.45:2.94Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
W/C=0.45Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
每立米混凝土各材料用量:Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水192kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
水泥 423kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
砂612kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
碎石1244kg/m3Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
3c3t - 2008/7/21 23:01:00
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Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
lidexing - 2008/7/27 23:44:00
非常感谢Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
晨思 - 2008/8/18 1:20:00
好用。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
noeyefish - 2009/12/16 22:32:00
不错。我收藏了。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
BBHHXX - 2009/12/22 20:01:00
谢谢!我收藏了。Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
lzx136 - 2010/1/7 13:16:00
非常感谢Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
doublefire - 2014/10/3 20:38:00
好东西!Ñ,- 6gÌÓ bbs.3c3t.comõgaøØ?:
1
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