泵送混凝土常见问题及解决途径.rar

泵送混凝土常见问题及解决途径

内容提要：随着建筑业的快速发展，泵送砼的应用已成为混凝土施工中必不可少的环节，但泵送砼常容易出现或这或那的问题，给施工进度及施工质量带来麻烦。本文就泵送砼常出现问题的原因加以分析，并给出一系列解决途径。
　　1 　砼外加剂对水泥的适应性
　　（1） 水泥矿石是否稳定导致矿物组分是否稳定，从而影响到砼外加剂对水泥的适应性。
　　（2） 水泥生产工艺，如立窑与回转窑，冷却制度中的急冷措施控制得怎样，石膏粉磨时的温度等，造成水泥中矿物组分、晶相状态，石膏形态发生改变，从而影响到砼外加剂对水泥的适应性。
　　（3） 水泥中吸附外加剂能力：C3A>C4AF>C3S>C2S，水泥水化速率与矿物组分直接相关。
　　（4） 水泥存放一段时间后，温度下降，使砼外加剂高温适应性得到改善，而且f-CaO吸收空气中的水后转变成Ca（OH）2，吸收空气中的CO2后转变成CaCO3，从而使Mwo下降，也使砼和易性得到改善，使新拌砼塌落度损失减缓，砼的凝结时间稍延长。
　　（5） 普通硅酸盐水泥的需水量稍大于矿渣水泥，其保水性好，但一般塌落损失也较快。
　　（6） C3A含量较高的水泥，塌落度损失快，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