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
Maximum Allowable Time From Initial Batching to Placement ...
I am involved with a large urban concrete project where concrete delivery is sometimes delayed by traffic congestion. The specification requires concrete placement within 90 minutes of batching at the plant. What is the significance of this 90-minute specLearn More
11 Best Method for Transportation of Concrete
Transit mixer is one of the most popular equipment for transporting concrete over a long distance mostly in RMC plant (Ready Mixed Concrete plant). Transit mixer is mounted on the truck and maybe having a capacity of 4 to 7 m 3. Concrete is continuously agitated in the truck with 2 to 6 revolution per minute.Learn More
Batching, Mixing, Transporting, and Handling Concrete, Chapter 10
Batching, Mixing, Transporting, and Handling Concrete. Fig. 10-3. Central mixing in a stationary mixer of the tilting drum type with delivery by a truck mixer operating at agitating speed. (69926) Fig 10-4. (top) Nonagitating trucks are used with central-mix batch plants where short hauls and quick concreteLearn More
90 Minute Rule - Eng-Tips Engineering Forums
How is concrete mixed at a batching plant?Learn More
Mixing and Transporting Concrete
Batching is the "process of weighing or volumetrically measuring and introducing into the mixer the ingredients for a batch of concrete" (Kosmatka, 94). Quality assurance, suitable arrangement of materials and equipment, and correct weighing of the materials are the essential steps that must be completed before any mixing takes place.Learn More
90 Minute Rule - Concrete Engineering general discussion ...
The question I was really asking was if concrete is first mixed at the site, why does the 90 minutes (US guideline) actually begin from the time of batching at the plant. This is a requirement in New York State DOT specifications.Learn More
Pavement Manual: Concrete Plant Operation
A batch plant is the concrete mix plant where the aggregates, cementitious materials, chemical admixtures, and water are metered and combined together to produce hydraulic cement concrete. A batch of concrete is the amount of material mixed at one time. The batch plant can be a commercial concrete batch plant or a temporary batch plant brought in and assembled by the contractor near the paving site. On large concrete paving projects, most contractors choose to mix their concrete using their ownLearn More
9 METHODS FOR TRANSPORTATION OF CONCRETE - CivilBlog.Org
May 03, 2014 · There are two variations. In one, mixed concrete is transported to the site by keeping it agitated all along at a speed varying between 2 to 6 revolutions per minute. In other category, the concrete is batched at the central batching plant and mixing is done in the truck mixer either in transit or immediately prior to discharging concrete at site.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