混凝土工程
一、混凝土生产与运输 | Concrete Production & Delivery
二、混凝土浇筑 | Concrete Placement
三、混凝土养护 | Concrete Curing
四、混凝土缺陷 | Concrete Defects
五、混凝土修补 | Concrete Repair
Mass Concrete Pour — Transformer Foundation
Wu, today we're pouring the main transformer foundation — 28 feet by 18 feet by 5 feet thick. That's about 93 cubic yards. This qualifies as mass concrete per ACI 301. What's your temperature control plan?
吴工，今天浇筑主变压器基础——28英尺×18英尺×5英尺厚。大约93立方码。 按ACI 301这属于大体积混凝土。温度控制方案是什么？
吴工: Correct. With a 5-foot thickness, we need to manage the temperature differential — the core vs. surface temperature should not exceed 35°F per ACI 301.
对。5英尺厚度的话，我们需要控制温差——按ACI 301核心与表面温差不得 超过35°F。
We're using a low-heat mix design: 50% Type II cement replaced with Class F fly ash. Maximum cement content is 400 lbs per cubic yard. The water-cement ratio is 0.42. This mix has a lower heat of hydration and slower strength gain — which is exactly what we want for mass concrete.
我们使用低热配合比：50%的II型水泥用F级粉煤灰替代。最大水泥用量 400磅每立方码。水灰比0.42。这个配合比水化热低、强度发展慢——正是大 体积混凝土需要的。
Good. What about the pour sequence? You can't just dump 93 cubic yards in one spot and call it done.
好。浇筑顺序呢？不能把93立方码倒一个点就完事了。
吴工: We'll pour in three lifts — roughly 20 inches each. The concrete pump will move systematically so each lift is placed before the previous lift takes initial set. No cold joints.
我们分三层浇筑——大约每层20英寸。泵车系统移动，确保上一层初凝前下 一层已浇筑。没有冷缝。
泵车到了吗？
Is the pump truck here?
泵车手: Pump is set up and the boom is in position. Ready when you are.
泵车已架好，布料杆就位。随时可以开始。
吴工: OK, first truck — what's the slump?
好，第一车——坍落度多少？
(sampling concrete) Slump is 5 inches. Spec is 4 to 6 inches. Good. Temperature of concrete at delivery: 72°F. Below the 80°F limit. Let's pour.
（取样）坍落度5英寸。指标4到6英寸。好。混凝土到场温度72°F。低于 80°F限值。开始浇筑。
(During the pour) Make sure the vibrator is fully inserted and slowly withdrawn. Don't use the vibrator to move the concrete horizontally — that causes segregation.
（浇筑中）确保振捣棒充分插入、缓慢拔出。别用振捣棒水平移动混凝土—— 那会导致离析。
I'm checking the lift thickness with a dip stick — 19, 21, 20 inches. Consistent.
我用探杆测每层厚度——19、21、20英寸。均匀。
吴工: After the pour, we start curing immediately. We'll cover with wet burlap and keep it continuously moist for 14 days. Also, I've embedded four thermocouples — two in the core and two near the surface. We'll monitor the temperature differential twice a day for the first week.
浇筑完立即开始养护。盖湿麻袋保持连续湿润14天。还有，我埋了4个热电 偶——2个在核心、2个靠近表面。第一周每天两次监测温差。
Sounds like a solid plan. If the differential approaches 35°F, we may need to insulate the surface to slow the cooling.
听起来方案挺靠谱。如果温差接近35°F，我们可能需要表面保温来减缓冷 却。
吴工: Agreed. We have insulation blankets on standby. Better to be prepared than to crack a transformer foundation.
同意。保温被已经备好了。有备无患，总比变压器基础开裂好。
Concrete QA/QC — Cylinder Testing and Defect Investigation
Feng, the 28-day cylinder breaks for the substation control building's first-floor slab came in. What are the results?
冯工，升压站控制楼一层板的28天试块结果出来了。怎么样？
冯工: Let me pull the data. We cast 4 cylinders on pour day. Batch #SW-047, design strength 4,000 psi. Results: Cylinder 1: 3,820 psi. Cylinder 2: 3,910 psi. Average: 3,865 psi.
我调数据。浇筑当天做了4个试块。批次#SW-047，设计强度4,000 psi。 结果：试块1：3,820 psi。试块2：3,910 psi。平均：3,865 psi。
That's below 4,000 psi. That's an NCR. And the average of two cylinders is below fc' — that fails ACI 318 acceptance.
低于4,000 psi。这是不符合项。而且两个试块平均值低于fc'——按ACI 318验收不通过。
冯工: Wait — the other two cylinders from this batch. Cylinder 3: 4,120 psi. Cylinder 4: 4,080 psi. Average of all four: 3,983. Still below spec, but closer. Per ACI 318, if the average of any three consecutive tests falls below fc', it's a fail.
等等——这一批另外两个试块。试块3：4,120 psi。试块4：4,080 psi。 四个平均值：3,983。还是低于指标，但接近了。按ACI 318，连续三组中的 任一组平均值低于fc'，不合格。
We need to investigate. Feng, pull the batch records. What was the water-cement ratio? The slump? The delivery time?
我们需要调查。冯工，调出批次记录。水灰比多少？坍落度？运送时间？
冯工: (checking records) W/C ratio was 0.48 — designed 0.45. The slump at the site was 6.5 inches — spec was 4 to 6 inches. It looks like water was added at the site.
（查记录）水灰比0.48——设计的0.45。现场坍落度6.5英寸——指标4到6 英寸。看起来现场加水了。
There it is. Someone added water to the truck. That increases the w/c ratio and kills the strength. Who released the truck?
原因在这儿。有人往罐车里加了水。水灰比一高，强度就完蛋了。谁放行 的这车？
冯工: I need to check the delivery ticket. (flips through) Here — ticket #3847. Arrived at 10:15 AM. Slump at arrival was 3 inches — too low. Note says "added 5 gallons of water to achieve 6-inch slump." The ticket is unsigned by QC.
我得查送料单。（翻找）这儿——#3847号单。10:15到。到场坍落度3英寸 ——太低。注释写着"加了5加仑水以达到6英寸坍落度"。QC没有签字。
That's a major procedure violation. No water addition without QC approval. Period. We need to address this with the concrete supplier AND our site crew.
这是严重违规。没有QC批准严禁加水。没得商量。这事需要同时找混凝土 供应商和我们的现场班组。
Structural: Let me talk about the slab itself. Even at 3,865 psi, is the structure safe?
我来说说楼板本身。即使3,865 psi，结构安全吗？
(after core drilling and analysis) We took three cores from the slab. Core strengths: 4,150, 4,280, 4,090 psi — all above 4,000. Per ACI 318, if the average of three cores exceeds 85% of fc' (3,400 psi) and no single core is below 75% (3,000 psi), the concrete is structurally acceptable.
（取芯分析后）我们从楼板钻了三个芯样。芯样强度：4,150、4,280、 4,090 psi——全部在4,000以上。按ACI 318，三个芯样平均值超过fc'的85% （3,400 psi），且没有单个芯样低于75%（3,000 psi），混凝土结构上可 以接受。
So the cylinders were bad but the in-place concrete is OK. That happens when cylinders are poorly made or cured. However, the water addition violation still stands. We issue an NCR for procedure violation, retrain the crew, and tighten the QC hold point on every truck.
所以是试块制作/养护的问题，但实体混凝土还行。试块做不好就会出现 这种情况。不过加水违规还是要处理。我们开不符合项报告、重新培训班组、 对每车都严格QC控制点。