For the purposes of this data sheet, hot weather is. Keep the subgrade and forms moist so they do not absorb water from the mix. July 1, 2018 concrete placement in cold and hot weather. Cold weather concretingdealing with the practical aspects of successfully placing concrete during cold weather a halfday technical seminar for all who deal with practical concreting either through specification, design, supervision onsite or construction. The success of many hotweather concreting operations depends on the steps taken to slow the cement hydration reactions within the concrete and to minimize the rate of evaporation of. Hot and cold weather concreting concrete cement scribd. Ppt hot weather concreting powerpoint presentation. Cold weather the current american concrete institute definition of coldweather concreting, as stated in aci 306 is, a period when for more than 3 successive days the average daily air temperature drops below 5c 40f and stays below 10c. Definitions overview of aci 306r10 guide to cold weather concreting objectives and principles effect of cold weather on concrete properties temperature of concrete as mixed as placed and maintained length of protection period temperature after. Hot weather references in the handout section of your goto webinar control panel.
India has regions of extreme hot weather hot humid and hot airdas well as cold weather. Guide to hot weather concreting reported by aci committee 305 aci 305r10 environmental factors, such as high ambient temperature, low humidity, high wind, or both low humidity and high wind, affect concrete properties and the construction operations of mixing, transporting, and placing of the concrete materials. Supplying the necessary supplemental heat required to ensure that forms, subgrades, and. Dont sweat hot weather concreting know your options duration. Use airentrained concrete when exposure to moisture and freezing and thawing conditions are expected. Cold weather concreting aci 306 effects and precautions.
Hot weather may be defined as any period of high temperature in which special precautions need to be taken to ensure proper handling, placing, finishing and curing of concrete. Download citation hot and cold weather concreting this chapter provides an overview of hot and cold water concreting. Aci 31811 building code requirements for structural concrete directs the user to aci 306r which serves as a guide cold weather concreting. Plan ahead be prepared be concerned schedule work instruct and inspect successful cold weather concreting. United states department of interior, bureau of reclamation. Cold weather concreting is possible when certain precautions are taken. Therefore, if cold weather concreting is performed, adequate protection. Hot and cold weather concreting jun 27 2016 0 comments concrete, nishkian monks 0 by serena gilles, pe. Hot weather concreting conditions typically include.
Aci 305, hot weather concreting, aci manual of concrete practice, part 2. This reference specification provides requirements for hot weather concreting that the architectengineer can apply to any construction project involving hot weather concreting by citing it in the project specification. Hot and cold weather concreting free download as word doc. In hot weather concreting, one should make sure that all the negative impacts of high ambient temperature are appropriately alleviated by taking the necessary precautions. Have equipment and materials ready before the hot weather arrives. Keep sunshades and windbreaks available and use them whenever possible. America n concrete institute aci committee 305 defines hot weather as any combination of high ambient temperature, high concrete temperature, low relative humidity, wind speed and solar radiation. Cold weather concreting do you have the right tools. This document guides specifiers, contractors, and concrete producers through the selection processes that identify methods for cold weather concreting. Pouring concrete when the heat is on hd supply white cap. Cip 12 hot weather concreting cip concrete blisters. This means concrete mixes, pours and placements are needed all year and cannot come to a halt due to lessthanideal weather conditions.
Cip 27 cold weather concreting cip 28 concrete slab moisture cip 29 vapor retarders under slabs on grade cip. High temperatures affect concrete at all stages of the production and. Have everything prepared before the readymix truck arrives. Newly placed concrete should be adequately insu lated to retain this heat and thereby maintain favorable curing temperatures. Good judgment is necessary to select the most appropriate compromise of quality, economy, and practicability. Hot weather concreting problems, effects and precautions.
Removing all ice and snow from the subgrade or formwork. Hot weather concreting detrimental hot weather conditions include. Concrete placement in hot weather planning, placing, and. Pouring concrete in hot and cold weather conditions requires special attention in order to achieve desirable strength and quality. Placing concrete in cold weather can be a challenge.
Cold weather concreting the irish concrete society. American concrete institute guide to cold weather concreting. Internal concrete temperatures must be tracked during hot weather placements, because hot weather can severely compromise overall concrete strength, performance, and durability. Apparently, thats not the case in many other parts of the globe due to different weather condition. Hot and cold weather concreting methods slideshare. Hot weather concreting in tropical countries, such as india, air temperatures may rise up to 4050 deg. It defines cold weather as, a period when for more than three successive days the average daily air temperature drops below 40 degrees fahrenheit and stays below 50 degrees for more than onehalf of any 24 hour period. Weather conditions have a profound effect on setting and curing. According to the american concrete institute aci 306r16. Planning a successful, wellrun, hotweather project is the result of thorough and careful planning. In order to promote public education and public safety, equal justice for all, a better informed citizenry, the rule of law, world trade and world peace, this legal document is hereby made available on a noncommercial basis, as it is the right of all humans to know and speak the laws that govern them.
Cip 27 cold weather concreting why consider cold weather. Information from the national ready mixed concrete association what is hot weather. Do not place concrete when the air temperaturemeasured at the location of the concreting operation is below 35of as determined by the rce unless authorized by the rce. These conditions warrant special precautions when placing, finishing, curing and protecting concrete against the effects of cold.
During cold weather concreting shall be abandoned when the temperature falls below 4. Place and maintain concrete at the recommended temperature. Weather conditions can have a dramatic effect on both the setting time and concrete placing, finishing and protection systems that must be followed for proper concrete placement. Cip 1 00 concrete in practice cip 1 dusting concrete surfaces. Extreme weather conditions extreme heat or cold, and humidity variations can significantly alter the quality of concrete.
Concrete placed during cold weather, protected against freezing, and properly cured for a sufficient length of time, has the potential to develop higher ultimate strength klieger 1958 and greater durability than concrete placed at higher. The objectives of cold weather concreting practices are to. Built constructions builtconstructions hot and cold. This and other problems can be avoided with precautionary steps. Hot and cold weather can lead to many problems in mixing, placing, and. Pdf cold weather concreting reported by aci committee 306. High temperature also accelerates cement hydration and contributes to the potential for thermal cracking in thicker concrete sections. Keep surfaces in contact with concrete free of ice and snow and at a temperature above freezing prior to placement. So, understanding hot weather concreting will benefit you all year round. Under normal weather conditions, concrete can set in 848 hours, reaching 70% strength in approximately seven days. Concrete protected from freezing until it attains a compressive strength of at least 500 psi will not be damaged by exposure to a single freezing cycle.
Use immersion thermometer inserted in concrete near forms or surface for recording temperature. Cold weather concreting to reduce the risk of concrete damage in cold weather, use the command center maturity monitoring system to estimate when inplace concrete has achieved sufficient strength. If requirements for cold weather concreting are needed in specification form, aci 306. Economic necessity to continue work in extremely hot weather. It then takes up to 28 days to fully cure and reach its full strength.
Hot weather concreting concreting in hot weather the. Hot weather problems are most frequently encountere. Successful cold weather concreting introduction cold weather can lead to many problems in mixing, placing, and curing of concrete that can have an adverse effect on its properties and service life. Cold weather concreting outline for todays presentation.
Set time accelerating admixtures allow concrete producers to decrease concrete setting time according to their specific project needs, across a wide range of ambient temperatures. Aci 305 hot weather concreting defines hot weathers as any combination of the following conditions that tends to impair the quality of the freshly mixed or hardened concrete. Proper use of the rebound hammer download pdf file. Cold weather concreting concreting in cold weather the. A key objective for coldweather concreting is preventing damage to the concrete from earlyage freezing. The most common problem is with having the concrete freeze andor go through freezethaw cycles before acquiring adequate strength. The indian standards dealing with extreme weather concreting are. This guide has been developed by basf to assist the entire construction team owners, specifiers, contractors, and readymixed concrete. Such temperatures combined with high wind velocity andor low humidity enhance the rate of evaporation of the water, increase the rate of hydration of cement, which factors reduce the setting time of the concrete.
Cold weather exists when the air temperature has fallen to, or is expected to fall below 40 f during the protection period. Neglect of protection against early freezing can cause immediate destruction or permanently weakened concrete. For example, according to aci 305, any combination of high ambient temperature, high wind, low relative humidity and solar radiation sunlight is a good enough precondition to label concreting as hot weather concreting. Today we address how to define cold weather concrete as described by the aci. We know concrete cures slower in cold weather, but how do we know when we need to take extra precautions in cold weather.
The city of mason cold weather concrete policy has been developed to be consistent with aci american concrete institute 318 and 306. India has regions of extreme hot weather hot humid and hotairdas well as cold weather. The protection period is defined as the time required to prevent concrete. Planning for hot weather conditions is essential because of the potential effects on fresh and recently placed concrete. Benefits of accelerating concrete setting time include. This standard covers recommended practiceor cold weather concreting. Guide to hot weather concreting american concrete institute. Take advantage of the opportunity provided by cold weather to place lowtemperature concrete. Efflorescence in concrete products download pdf file. Hot weather concreting effect of hot weather on concrete. Aci documents are available in print, by download, on cdrom, through electronic subscription, or reprint and may be obtained by contacting aci. A free powerpoint ppt presentation displayed as a flash slide show on id. Guide to cold weather concreting is one of many numerous, valuable resources on cold weather concrete practices by the american concrete institute aci.