What is the Allowed Time for the Concrete Discharge?
Dec 08, 2017 · For plain concrete without any admixtures, I agree that the required time from the batching time until to the placement of concrete is 1 1/2 hr as per ASTM. However, by the introduction of admixtures either mineral or chemical admix the quality of concrete will be inhanced and setting time property will be prolonged, so the 1 1/2hr required ...Learn More
Concrete Discharge Time Requirements - ASCC
to the batch. This waiver is seldom used because the reasons for allowing the waiver are not well understood. ASTM STP 169D, Significance of Tests and Properties of Concrete and Concrete-Making Materials, includes Chapter 45, “Ready Mixed Concrete,” by Lobo and Gaynor. They state that the 1-1/2 h time limit is too conservative and thatLearn More
It's About Time| Concrete Construction Magazine
Dec 06, 2012 · Often the producer must batch concrete and measure air content at several intervals over the desired transit time for a project. We have been involved with several of these projects where pressure meter tests are taken and cylinders are cast for hardened air content and strength measurements every 15 or 30 minutes after initial batching.Learn More
Time Limit Between Pours to Avoid Cold Joints| Concrete ...
We don't find any reference to a set time limit in the American Concrete Institute (ACI) building code or specifications for structural concrete. That's probably because time isn't the only factor to consider. In cool, damp weather you can wait longer to place the next batch than you can during hot, dry weather.Learn More
How does a concrete batch plant work | Operation of concrete mixer
What is a concrete batch plant?Learn More
Table 1 Setting Time of Concrete at Various Temperature
Use of Admixture and Its Effects on Setting Time. Initial set, as defined by ACI 116R, is a degree of stiffening of a mixture of cement less than final set, generally stated as an empirical value indicating the time in hours and minutes required for the cement paste to stiffen sufficiently to resist to an established degree, the penetration of a weighted test needle.Learn More
Batching, Mixing, Transporting, and Handling Concrete, Chapter 10
time, about 1 or more hours, can result in concrete strength loss, temperature rise, excessive loss of entrained air, and accelerated slump loss. When truck mixers are used, ASTM C 94 (AASHTO M 157) also limits the time between batching and complete discharge of the concrete at the job site; this time is 1. 1 ⁄ 2Learn More
90 Minute Rule - Concrete Engineering general discussion ...
Check out Neville's book Properties of Concrete. He has a good discussion. There are two types of mixing - central plant mix and truck mix. In the later, there is a 90minute rule about the time the moist aggregate can be in contact with the cement (in UK it is 2 hours).Learn More
When Is it Too Cold to Pour Concrete? | Hunker
Mar 31, 2019 · Concrete is one of the most versatile materials used in modern construction and one of the most important. While concrete can be poured at any time of year, there is an ideal range of temperature in which to pour concrete. If it's too cold or too hot outside, you will need to take precautions.Learn More
How does a concrete batch plant work | Operation of concrete ...
May 25, 2017 · Before we understand the working or operation of a concrete batch plant.It is important to understand the basic components and structure of a batching plant. We have mobile concrete plants installations in Philippines’s city like: Bulacan, Cavite and Pampanga. It is a machine that combines various ingredients like aggregates, sand, water, cement and additives.These components are first ...Learn More