Basic Guides for Hot Weather Concreting

 Dear Readers,

This article is in continuation with my previous posts of Hot Weather Concreting and Concrete Precautions. Following points are the simple basic guides for Hot Weather Concreting.

While hot weather conditions are commonly encountered in summer, combinations of high temperatures, winds and low humidity could result in conditions leading to problems with concrete placement and finishing at any time. Hot weather is any combination of:

High ambient temperature;

Low relative humidity;

High wind

AS 13791 places a 35°C limit on the maximum concrete temperature at the time of delivery. However, when the air temperature rises above 30°C, it is usually recommended that precautions be taken, particularly if there is also hot dry wind.

1.     Plan in advance. Have equipment and materials ready before the hot weather arrives during the pouring day.

2.       Keep the subgrade and forms moist so they do not absorb water from the mix.

3.       Keep sunshades and windbreaks available and use them whenever possible.

4.       Have everything prepared before the ready-mix truck arrives. Don’t make the truck wait for you.

5.     Keep in constant communication with the ready-mix concrete provider. Coordination between the contractor and the producer is key.

6.       Concrete should be placed, struck off and Darby immediately.

7.     Use evaporation retardants, fogging or misting with water, or cover with a vapor-proof sheet after screeding (Finishing works). This will help prevent rapid drying, crusting, plastic shrinkage and rubber sets.

8.     Temporary covers, like continuously moistened burlap, may be placed over the fresh concrete and removed in small sections immediately ahead of the finishers.

9.      Substituting a burlap drag or broom finish will eliminate other high-risk finishing practices, such as smooth trowel finish.

10.   Curing should take place when the surfaces are hard enough to resist marring.

11.   Seal with a good, quality sealer for a minimum of 30 days after placing and curing.

12.   Remember to protect the crew in high temperatures. Drink plenty of fluids and be careful with long exposure to the sun.

13.   Use PPE’s for workmen and rest shed (minimum 15% additional workforce)

14.   Ensure the machinery technicians at work location to attend minor repairs immediately.

15.       Have standby equipment and manpower for all stages

16.       Programme concreting for the cooler parts of the day, or even schedule night-time placement if possible.

17.       Plan the locations of construction joints ahead of time with hot weather contingencies in mind.

18.       Keep all equipment that touches the concrete cool (chutes, conveyors, pump lines, tremies, reinforcement and buggies). Protecting equipment from the direct sun will If it can’t be kept continuously cool, spray-cool it as necessary with water.

19.       Use a thermometer to monitor the temperature at which concrete is being delivered, and call for adjustments at the plant if necessary.

20.       Avoid delays at all stages. 

Wish You all the Best for Excellent Concreting during Hot Weather. Have a Nice Day!!!