The cement temperature is too high, resulting in the loss of concrete slump too fast.

某工程在6月份澆注C30梁板過程中，發現混凝土坍落度損失很快，造成滾筒內混凝土結料。

In the process of pouring C30 beam and slab in June, it was found that the slump loss of concrete was very fast, resulting in the concreting in the roller.

原因分析：經查所進水泥溫度達80℃，且水泥普遍偏細，造成需水量增大，當用水量不足時產生坍落度損失過快。

Cause analysis: the temperature of cement is 80 ℃ and the cement is generally fine, which increases the water demand. When the water consumption is insufficient, the slump loss is too fast.

防止措施：在夏秋季節5-10月份，對直接從水泥廠或粉磨站短途運輸進貨的水泥，必須每車測量水泥溫度要小于65℃。

Preventive measures: from May to October in summer and autumn, for cement directly transported from cement plant or grinding station for short distance, the temperature of cement must be less than 65 ℃.

外加劑冬期時結晶，堵塞管道。

The additive crystallized in winter and blocked the pipeline.

在11月到次年2月份，由于氣溫下降較快，在外加劑泵抽料到秤斗時會出現較多結晶，堵塞管道和蝶閥，造成計量緩慢。

From November to February of the next year, due to the rapid drop of temperature, more crystals will appear when the additive pump pumps the material to the scale bucket, blocking the pipeline and butterfly valve, resulting in slow metering.

原因分析：公司在用的萘系減水劑中Na2SO4在氣溫較低時，達到過飽和而析出晶體。

Cause analysis: Na2SO4 in naphthalene superplasticizer used by the company reaches supersaturation and precipitates crystal at low temperature.

防止措施：與減水劑供應商協商調整減水劑配方，由含固量由32%降到20%含固量，已基本解決析晶問題。

Preventive measures: negotiate with the water reducing agent supplier to adjust the formula of the water reducing agent, and reduce the solid content from 32% to 20%, which has basically solved the crystallization problem.

雨水或沖水進入外加劑罐，造成濃度降低，影響混凝土坍落度。

Rainwater or flushing water into the admixture tank, resulting in the concentration reduction, affecting the concrete slump.

某日開始供應工程的混凝土出廠前由檢測臺檢查時均發現坍落度偏小情況。

The slump of the concrete supplied on a certain day was found to be too small when it was checked by the test bench before leaving the factory.

原因分析：檢查減水劑罐上方進料口被人打開后未蓋好蓋子，下暴雨及可能沖洗罐頂的水流入罐內，造成減水劑濃度下降。

Cause analysis: check that the feed inlet above the superplasticizer tank is not covered properly after being opened, rainstorm and water that may flush the tank top into the tank cause the concentration of superplasticizer to drop.

防止措施：進料供應商在將減水劑泵到罐內后，應及時將上方蓋子蓋嚴，材料員加強巡察。

Preventive measures: after the feed supplier pumps the superplasticizer into the tank, the upper cover shall be closed in time, and the material man shall strengthen the inspection.

將木鈣減水劑誤用為萘系減水劑造成緩凝。

The wood calcium superplasticizer was misused as naphthalene superplasticizer to cause retarding.

在供應某工程二層梁板時，施工單位反映凝結時間太長，澆筑后24小時仍未凝固。

In the supply of the second floor beam and slab of a project, the construction unit reflected that the setting time was too long, and it did not set 24 hours after pouring.

原因分析：經檢查配合比下料記錄，普通減水劑被當作減水劑輸入電腦，減水劑主要以萘系為主，按粉劑摻量為0.5%～0.8%，而普通減水劑主要成分為木質素磺酸鈣，摻量為0.25%～0.3%。當木鈣超過膠結材料用量0.4%時就會出現嚴重緩凝。

Cause analysis: according to the record of mix proportion cutting, ordinary superplasticizer is input into the computer as high range superplasticizer. High range superplasticizer is mainly composed of naphthalene, with the dosage of 0.5% ~ 0.8% according to the powder, while ordinary superplasticizer is mainly composed of calcium lignosulfonate, with the dosage of 0.25% ~ 0.3%. When the amount of wood calcium exceeds 0.4% of cementitious material, serious retarding will occur.

糾正措施：使用木鈣減水劑摻量應嚴格控制，配合比輸入時必須有另外操作員復核。

Corrective measures: the dosage of wood calcium superplasticizer should be strictly controlled, and the input of mix proportion must be checked by another operator.

不同品牌防水劑混合使用。

Different brands of waterproof agent mixed use.

某工程地下室外墻C40P8施工，發現一車混凝土坍落度偏大退回。

During the c40p8 construction of the basement exterior wall of a project, it was found that the slump of a truck of concrete was too large.

原因分析：經檢查進貨記錄，同期進貨的兩種防水劑用于兩個工程中，一種有明顯減水作用，另一種減水率較少，工人在搬運袋裝防水劑時出現混雜使用的情況。

Cause analysis: after checking the purchase records, two kinds of waterproof agents purchased in the same period were used in two projects, one had obvious water reducing effect, the other had less water reducing rate, and the workers used mixed waterproof agents when carrying bags.

糾正措施：每批防水劑（包含膨脹劑等）進廠時必須復檢合格才能使用，倉庫物資堆放應隔離和標識，不得混用。

Corrective measures: each batch of waterproof agent (including expansive agent, etc.) must be rechecked and qualified before use. Materials in the warehouse shall be isolated and marked, and shall not be mixed.

[實例6] 砂中含有大塊的泥塊和卵石。

[example 6] the sand contains large pieces of mud and pebbles.

在某工地泵送施工時發現泵車下料斗上有較多大塊鵝卵石和泥塊。

During the pumping construction in a construction site, it is found that there are many boulders and mud blocks in the hopper of the pump truck.

原因分析：砂場供應河砂在抽砂時篩網破損，抽料口插入太深，將河床底部的大塊石頭和泥團抽到砂中。

Cause analysis: the screen mesh of river sand supplied by sand yard was damaged during sand pumping, and the pumping hole was inserted too deep, which pumped large stones and mud masses at the bottom of riverbed into sand.

糾正措施：砂場應定期檢查抽砂機篩網是否破損，公司砂石進料口及主機樓待料槽應加裝隔柵，防止雜物進入混凝土。

Corrective measures: the sand yard should regularly check whether the screen of the sand extractor is damaged, and the company's sand and gravel inlet and the main building's waiting trough should be equipped with barriers to prevent debris from entering the concrete.

[實例7] 碎石含泥量超標。

[Example 7] the mud content of crushed stone exceeds the standard.

雨天后所進碎石含泥量超過1%，造成混凝土需水量增大，混凝土強度下降。

When the mud content of crushed stone exceeds 1% in rainy days, the water demand of concrete increases and the strength of concrete decreases.

原因分析：下雨后碎石破碎過程含大量砂土，振動篩分時無法分離干凈。

Cause analysis: there is a large amount of sand in the process of crushed stone crushing after rain, which cannot be separated completely during vibration screening.

糾正措施：在上料碼頭增加沖水設備，將含泥量控制在標準范圍內。不合格碎石嚴禁進倉。

Corrective measures: add flushing equipment in the loading dock to control the mud content within the standard range. Unqualified gravel is not allowed to enter the warehouse.

粉煤灰、礦渣質量不合格。

The quality of fly ash and slag is unqualified.

公司采購F類一級灰，進廠時細度、需水量比和燒失量等指標偶爾達不到要求；采購的S95級磨細礦粉，7天和28天活性指標偶爾達不到要求，但檢測周期長。

The fineness, water demand ratio and loss on ignition of class F grade I ash purchased by the company occasionally fail to meet the requirements; The activity index of S95 grade ground ore powder purchased in 7 days and 28 days can not meet the requirements occasionally, but the detection cycle is long.

原因分析：電廠燃煤質量出現波動，粉煤灰分選設備出現故障，引起質量波動；礦渣來源不穩定，比表面積偏小。

Cause analysis: the coal quality of the power plant fluctuates, and the failure of the fly ash separation equipment causes the quality fluctuation; The source of slag is unstable and the specific surface area is small.

糾正措施：每車粉煤灰和礦渣粉進廠后應檢查細度或需水量比合格才能入庫。每車檢測礦渣比表面積≥400㎡/kg合格才能進庫，定期到供應廠抽樣。

Corrective measures: each vehicle of fly ash and slag powder should be checked for fineness or water demand ratio after entering the plant, and then they can be put into storage. Only qualified slag with specific surface area of more than or equal to 400 m2 / kg can it be put into the warehouse and sampled at the supply plant regularly.

水泥、粉煤灰和礦粉等粉狀物進倉前須經篩網過濾。

Cement, fly ash, mineral powder and other powder materials must be filtered through the screen before entering the warehouse.

主機樓操作員反映螺運機被雜物卡住，造成電機燒毀。

The operator of the main engine building reported that the screw conveyor was stuck by debris, causing the motor to burn down.

原因分析：散裝物料進倉時，含有鐵釘、鋼球等球磨機中雜物，卡入螺運機間隙。

Cause analysis: when the bulk materials are put into the warehouse, there are impurities in the ball mill such as iron nails and steel balls, which are stuck into the clearance of screw conveyor.

糾正措施：所有進料管口前加裝φ10mm孔徑的篩網，防止大塊雜物進入罐中。

Corrective action: all feed pipe orifices are equipped with φ The screen with a diameter of 10 mm can prevent large debris from entering the tank.