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c20c30c40混凝土配合比设计计算步骤 [复制链接]

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t T
发表于 2008-07-21 22:44 |显示全部
c20c30c40混凝土配合比设计计算步骤(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

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

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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发表于 2008-07-21 22:46 |显示全部

回复：c20c30c40混凝土配合比设计计算步骤

原始资料：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
设计步骤：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（一）设计初步配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1、确定混凝土配制强度（Ryp=Ry+1.65б=30+1.645×5=38.2MPa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2、计算水灰比（w/c）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（1）按强度要求计算水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
           Rs=RCRb=1.13×42.5=48MPa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（2）计算混凝土水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
w/c=ARs/Ryp+ABRs=0.48×48/38.2+0.48×0.52×48=23/50.1=0.46(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（3）按耐久性校核水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
    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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
3、选定单位用不水量（Mwo）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
   由于碎石最大粒径40mm，选用混凝土用水量：Mwo=175Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
4、计算单位用灰量（Mco）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（1）按强度计算单位用灰量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
      Mco= Mwo/ w/c=175/0.46=380 Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（2）按耐久性校核单位用灰量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
5、选择砂率（βs）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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%。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
6、计算砂石用量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（1）采用质量法(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
已知：单位用灰量Mwo=175 Kg/m3，砂率βs=33%(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
      Mso+Mgo=Pcp－Mco－Mwo(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
      Mso/Mso+Mgo=0.33(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
假设混凝土混合料湿表观密度Pcp=2400 Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
     Mso+Mgo=2400-380-175(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
     Mso/Mso+Mgo=0.33(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
解得砂用量Mso=609 Kg/m3,碎石用量Mgo=1236 Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
按质量法计算初步配合比:(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
     Mco : Mwo : Mso : Mgo =380 : 175 : 609 : 1236(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
即:  1 : 0.46 : 1.6 : 3.25 w/c=0.46(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(二)试拌混凝土,提出基准配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2、提出基准配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
   Mca ：Msa ：Mga=1 ：1.6 : 3.25, w/c=0.46(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(三)检验强度,测定试验室配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1、检验强度(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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=0.42(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2、确定试验室配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
        Msb+Mgb=2400-417-175(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
        Msb/ Msb+ Mgb=0.33(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
即Msb=596,Mgb=1213(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
修正后配合比Mcb:Msb:Mgb=417:596:1213=1:1.43:2.91(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水灰比Mwb/Mcb=175/417=0.42(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
计算湿表观密度Pcp=417+175+596+1213=2401 Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
实测湿表观密度P＇cp=2400 Kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
修正系数б=2400/2401=1(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
因此试验室配合比为Mcb＇:Msb＇:Mgb＇=1:1.43:2.91, w/c=0.42(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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发表于 2008-07-21 22:47 |显示全部

回复: c20c30c40混凝土配合比设计计算步骤

C40混凝土配合比设计(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
材料选择(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水泥：采用牡丹江产P.O42.5普通硅酸盐水泥。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
砂：产地岔林河，细度模数2.62属于中砂，颗粒级配属 Ⅱ区。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
粗集料配合比设计(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
根据筛分结果粗集料的掺配比例为: 4.75～16cm cm碎石为35%(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
16～31.5cm cm碎石为65%。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
　　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.(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
配合比设计(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1、计算初步配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1）确定混凝土配制强度（fcu,o）。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
混凝土设计强度fcu，k=40Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
标准差σ=5.0 Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
则混凝土配制强度：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
fcu,o= fcu，k+1.645×σ=48.2 Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2）计算水灰比（W/C）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（1）按强度要求计算水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
①计算水泥实际强度(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
采用42.5普通硅酸盐水泥fce,k=42.5Mpa，富余系数γc=1.13(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
则水泥实际强度为：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
fce=fce,k×γc =48.0Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
②计算水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
碎石 A=0.48(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
B=0.52(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
W/C=A×fce/(fcu,o+A ×B ×f ce)=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（2）按耐久性校核水灰比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（3）确定单位用水量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
确定混凝土的单位用水量为：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mwo=185kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（4）计算单位水泥用量（mco）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
①按强度计算单位用灰量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
已知混凝土单位用水量为(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mwo=185kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水灰比W/C=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
则计算单位混凝土用灰量：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mco=mwo×c/w=411kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
②按耐久性校核单位用灰量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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/m3。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（5） 确定砂率（SP）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
根据碎石的最大粒径为30mm，且水灰比为0.45 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
选定混凝土砂率为:(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
SP=33%(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（6）计算粗，细集料单位用量（mgo , mso）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
假定混凝土毛体积密度为2400 kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
185+411+ mgo+ mso=2400 ¨¨¨¨¨①(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mso×100/(mso+mgo) =33%¨¨¨¨¨②(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
解式①、②得：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mso=595 kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mgo=1209kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
则混凝土初步配合比为：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mco: mso: mgo=1:1.45:2.94(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
W/C=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2、试拌调整，提出基准配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1）计算试拌材料用量(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
按计算初步配合比试拌15L混凝土拌和物，各种材料用量：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水泥：411×0.015=6.165kg(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水：185×0.015=2.775kg(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
砂：595×0.015=8.925kg(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
碎石： 1209×0.015=18.135kg(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2)调整工作性，提出基准配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
性良好，满足施工和易性要求，因此提出基准配合比为：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mco: mso: mgo=1:1.45:2.94 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
W/C=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
3、检验强度(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
　　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:(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
430 kg/m3 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
411 kg/m3 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
394 kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2 8天后抗压强度分别见下表:(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水灰比:0.43(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
试件编号

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

1(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

23456
抗压强度

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

51.5(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

52.0(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

52.1(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

53.5(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

52.6(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

51.8(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

平均值

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

52.3Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水灰比:0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
试件编号

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

1(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

23456
抗压强度

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

49.2(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

49.5(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

47.9(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

48.5(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

48.3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

47.2(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

平均值

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

48.4Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水灰比:0.47(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
试件编号

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

1(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

23456
抗压强度

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

45.3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

43.2(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

45.5(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

44.7(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

43.8(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

44.2(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

平均值

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

44.5Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí

(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
　　２）、绘制灰水比和强度曲线:(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
强度(Mpa)(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
灰水比    （ 略　）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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。(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
4、确定试验室配合比(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1）强度修正(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
用水量mwb=185kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水泥用量 mcb =411kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
砂用量msb =595kg/m3 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
碎石用量 mgb =1209kg/m3 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
实测混凝土拌和物的毛体积密度为ρh=2470kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
校正系数K=2470/2400=1.03(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
修正后混凝土各材料用量为(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水185×1.03=190kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水泥411×1.03=423kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
砂595×1.03=612kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
碎石1209×1.03=1244kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
则试验室配合比为mcbsbgb=1:1.45:2.94(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
W/C=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
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：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
试件编号123456
抗压强度(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（Mpa）		48.549.248.749.247.945.9
试件编号789101112
抗压强度(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(Mpa)		48.948.051.752.449.248.7
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2)、强度评定(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
1、计算实测强度的平均值（mfcu）及标准差（sfcu）(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
标准差sfcu=1.68(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
平均值mfcu=49.0Mpa(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
2、根据试件组数（N=12）判定合格系数(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
λ1=1.70 (õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
λ2=0.9(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
3、强度评定(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（1）mfcu-λ1sfcu≥0.9fcu.k(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
49.0-1.7×1.68=46.1Mpa>0.9×40=36.0Mpa　　　合格(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
（2）fcu.min≥λ2fcu.k(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
45.9Mpa≥0.9×40=36.0Mpa　　　合格(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
故该12组混凝土试件块强度评定合格(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
上述式中：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
sfcu ————混凝土强度标准差(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mfcu————混凝土强度平均值(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
fcu.k————混凝土设计强度值(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
fcu.min————混凝土强度的最小值(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
λ1 . λ2————评定合格系数.查表得出(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
5、结论：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
经过理论推算和试验室结果，确定最终配合比：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
mcbsbgb=1:1.45:2.94(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
W/C=0.45(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
每立米混凝土各材料用量：(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水192kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
水泥 423kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
砂612kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
碎石1244kg/m3(õeìiîzŠ­bbs.3c3t.comó¶Iö؄\Tí
最后编辑3c3t 最后编辑于 2008-07-21 22:54:42
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