5 Tips for Hot Weather Concreting

极端天气条件（极端热或冷，湿度变化）可以显着改变混凝土的质量。在热的天气混凝土，应确保通过采取必要的预防措施适当地减轻了高环境温度的所有负面影响。在本文中，我们将审核如何热的天气温度会影响质量的混凝土有限公司nstruction. We will also review some of the most important precautions for concreting during the hot season.

What is Hot Weather for Concreting?

让我们看看混凝土的热温是什么，为什么它是至关重要的。American Concrete Institute(ACI) definition of hot weather condition, as stated in theACI-305R-10，是指加速的就业现场条件rate of moisture loss要么rate of cement hydrationof freshly mixed concrete, including:
一种）Ambient temperature of27 °C (80°F)要么higher; and
b)Evaporation rate that exceeds1 kg/m2/h
Canadian Concrete Design code (CSA A23.1/.2) uses the same ambient temperature for hot weather (27 °C).

炎热天气混凝土的挑战

How does hot temperature affect concrete? We know that water is a main component in concrete. Increase in the weather temperature increases the rate of vaporization, therefore,热的天气condition increases the water demand in concrete production. Other challenges of hot weather concreting can be summarized as:

1-Accelerated slump loss leading to the addition of water on the job-site,
2-增加率Settingresulting in placing and finishing difficulties,
3-在creased tendency for thermal and plastic cracking,
4-提示早期固化的批判需要，
5-控制夹带空气的困难，
6-在creased concrete temperature resulting in long term strength loss.

Precautions for Hot Weather Concreting

Following general precautions will help in performing a successful concreting project in hot weather conditions, and mitigating the negative impacts of hot weather. These precautions would be helpful during concrete production and delivery, and will improve thedurability performance of concreteby minimizing undesired cracking.

1-Use materials and mix proportions that have a good record in hot-weather conditions,
2-冷却混凝土或其一种或多种成分，
3-Use a concrete consistency that allows rapid placement and consolidation,
4-Reduce the time of transport, placing and finishing as much as possible,
5-Schedule concrete placements to limit exposure to atmospheric conditions (i.e. at night or during favorable weather conditions).

General Solutions for Cooling Materials

冷却混凝土的通常方法是在混合前降低混凝土材料的温度。由于这些材料对混合后的混凝土温度比其他成分相比，这些材料应保持可行的聚集体和混合水作为可行的。在极端热状态下，可以用冰层替换一部分水以降低温度。混凝土的固化在降低炎热天气对混凝土质量的负面影响方面发挥着重要作用。