建材里非常怕潮的粉体，不是水泥，是石膏。水泥受潮只是慢硬，石膏吸潮会提前水化，开封前看包装完好没用，到工地先查“活性”才靠谱。

The most moisture sensitive powder in building materials is not cement, but gypsum. Cement only hardens slowly when it gets damp, while gypsum will hydrate prematurely when it absorbs moisture. Before opening, check if the packaging is intact and it is useless. Only by checking the "activity" at the construction site can it be reliable.

先按用途拆标准，不混称：

First, disassemble the standards according to their intended use, without mixing them:

建筑石膏粉（找平打底基料）：走 GB/T 9776-2022，看类别代号 N/S/P（天然/脱硫/磷），2h 湿强度、初凝≥3min、终凝≤30min；

Building gypsum powder (leveling base material): follow GB/T 9776-2022, check the category code N/S/P (natural/desulfurization/phosphorus), with a wet strength of 2 hours, initial setting ≥ 3 minutes, and final setting ≤ 30 minutes;

轻质抹灰石膏（内墙找平成品）：走 GB/T 28627-2023，保水率≥90%、粘结强度≥0.6MPa、初凝≥1h、终凝≤8h；

Lightweight plastering gypsum (finished product for interior wall leveling): according to GB/T 28627-2023, water retention rate ≥ 90%, bonding strength ≥ 0.6MPa, initial setting ≥ 1h, final setting ≤ 8h;

湿区（厨卫阳台）别用普通石膏，选防水型或改水泥基，气硬性材料遇水软化。

Do not use ordinary gypsum in wet areas (kitchen, bathroom, and balcony), choose waterproof or cement-based materials, and use air hardening materials that soften when exposed to water.

采购单把“形容词”换成可检项：

Replace 'adjective' with 'detectable item' in the purchase order:

批号喷码和第三方 CMA 报告批号一致，不一致退；

Batch number spray code and third-party CMA report batch number are consistent, inconsistent return;

脱硫/磷石膏要附氯离子、可溶磷、氟含量，防后期返霜发绿；

The desulfurization/phosphogypsum should have chloride ions, soluble phosphorus, and fluoride content to prevent frost and green discoloration in the later stage;

放射性内照射/外照射指数均≤1.0，环保走 GB 18582；

The radioactive internal/external irradiation index is ≤ 1.0, and the environmental protection follows GB 18582;

袋装防潮复合膜，散装罐车查含水率，结块粉严禁过筛再用。

Bagged moisture-proof composite film, check the moisture content of bulk tank trucks, and prohibit sieving and reusing agglomerated powder.

到货三道关：

Three checkpoints upon arrival:

库房垫高离地20cm、离墙30cm，湿度≤65%，结块即废；

The warehouse should be elevated 20cm above the ground and 30cm above the wall, with a humidity of ≤ 65%, and any clumps should be considered as waste;

同批每批抽样，小样加水试凝：初凝太快（<30min）疑掺假或缓凝剂失控；

Sampling from each batch of the same batch, adding water to test the setting of the small sample: if the initial setting is too fast (<30 minutes), there is suspicion of adulteration or loss of control of the retarder;

机喷前先打3㎡样板墙，测拉伸粘结、平整度、空鼓，再定水灰比。

Before machine spraying, make a 3 ㎡ sample wall, measure the tensile bonding, flatness, and hollowing, and then determine the water cement ratio.

施工别踩两条线：

Do not step on two lines during construction:

加气块/砼交界挂耐碱网（≥160g/㎡，搭接≥100mm），砼面滚界面剂；

Hang alkali resistant mesh (≥ 160g/㎡, overlap ≥ 100mm) at the junction of aerated block/concrete, and use concrete surface rolling interface agent;

单遍底层8–20mm，面层≤5mm，初凝结块浆料不二次加水。

Single layer bottom layer 8-20mm, surface layer ≤ 5mm, initial agglomeration slurry should not be added with water again.

石膏真实成本 = 有效活性粉占比 × 可施工窗口 × 空鼓率。粉再便宜，批号对不上、受潮结块，上墙就是掉粉开裂。

The true cost of gypsum is calculated as the proportion of effective active powder multiplied by the construction window and the hollowing rate. No matter how cheap the powder is, the batch number doesn't match, it gets damp and clumps, and when it comes to the wall, the powder will fall off and crack.