泵送混凝土常見問題及解決途徑.rar

泵送混凝土常見問題及解決途徑

內容提要：隨著建筑業的快速發展，泵送砼的應用已成為混凝土施工中必不可少的環節，但泵送砼常容易出現或這或那的問題，給施工進度及施工質量帶來麻煩。本文就泵送砼常出現問題的原因加以分析，并給出一系列解決途徑。
　　1 　砼外加劑對水泥的適應性
　　（1） 水泥礦石是否穩定導致礦物組分是否穩定，從而影響到砼外加劑對水泥的適應性。
　　（2） 水泥生產工藝，如立窯與回轉窯，冷卻制度中的急冷措施控制得怎樣，石膏粉磨時的溫度等，造成水泥中礦物組分、晶相狀態，石膏形態發生改變，從而影響到砼外加劑對水泥的適應性。
　　（3） 水泥中吸附外加劑能力：C3A>C4AF>C3S>C2S，水泥水化速率與礦物組分直接相關。
　　（4） 水泥存放一段時間后，溫度下降，使砼外加劑高溫適應性得到改善，而且f-CaO吸收空氣中的水后轉變成Ca（OH）2，吸收空氣中的CO2后轉變成CaCO3，從而使Mwo下降，也使砼和易性得到改善，使新拌砼塌落度損失減緩，砼的凝結時間稍延長。
　　（5） 普通硅酸鹽水泥的需水量稍大于礦渣水泥，其保水性好，但一般塌落損失也較快。
　　（6） C3A含量較高的水泥，塌落度損失快，保水
Pumping Concrete Frequently Asked Questions and Solutions

Abstract: With the rapid development of the construction industry, pumping concrete applications has become an essential part of concrete construction, but often prone to pump concrete or a this or that problem, to the construction schedule and construction quality trouble . In this paper, pumping concrete often cause problems for analysis, and gives a solution.
A concrete additive to cement the adaptability
(1) cement stability of lead ore mineral composition is stable, thus affecting the adaptability of concrete admixtures on the cement.
(2) cement production process, such as the shaft and the rotary kiln, cooling system, measures to control how well the quench, the temperature of gypsum during grinding, resulting in the mineral composition of cement, crystalline state, gypsum morphology changes, which affect the to the adaptability of concrete admixtures on the cement.
(Three) in cement admixture adsorption capacity: C3A> C4AF> C3S> C2S, mineral composition of cement hydration rate and directly related.
(4) cement stored for some time, the temperature dropped, so that high adaptability of improved concrete additive, and f-CaO absorption of air into the water after the Ca (OH) 2, after absorption of CO2 in the air into CaCO3, so Mwo down also improved concrete workability, so that fresh concrete slump loss mitigation, concrete's setting time was slightly extended.
(5) ordinary Portland cement slag cement water demand is slightly larger than its water retention is good, but the general slump loss was faster.
(6) C3A content of the higher cement, slump loss of fast water
 

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