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INTRODUCTION. Bleeding in concrete is sometimes referred as water gain. It is a particular form of segregation, in which some of the water from the concrete comes out to the surface of the concrete, being of the lowest specific gravity among all the
This document contains a history of the development of mass concrete practice and discussion of materials and concrete mixture proportioning, p roperties, construction
The four elements of an effective temperature control program, any or all of which may be used for a particular mass concrete project, are: Cementitious material content
This chapter cov-ers cracking of hardened concrete due to drying shrinkage, factors influencing shrinkage, control of cracking, and the use of expansive cements to
Basic principles of concrete mixture design are initially addressed to give a brief overview as to how different types and amounts of materials affect the properties of concrete.
Curing is the process of controlling moisture and temperature to accelerate the concrete\'s hardening. Properly curing the concrete is important to ensure it reaches its full strength.
Understanding mass concrete is the key to controlling temperatures and ultimay saving time, efforts, and money. This article briefly describes mass concrete issues and
The control of the concrete temperature to prevent cracking can be viewed as principal goal in the design and construction of mass concrete. This paper
concrete; however, it has been used to successfully precool concrete to 34°F for highly specialized mass concrete placements. Post-Cooling of Concrete Use of cooling pipes in mass concrete is sometimes used to reduce maximum concrete temperatures and to quickly reduce interior temperatures. This method can have high initial and operating
The amount of mixing water in the concrete at the time of placement is normally more than required for hydration that must be retained for curing. However, excessive loss of water by evaporation may reduce the amount of retained water below what necessary for development of desired properties. For routine testing use test method D 1309
The hydration of cement can release a substantial amount of heat that can be problematic in mass concrete structure. This heat of hydration (HH) can produce thermal stresses that can crack the concrete and compromise the integrity of the structure leading to its failure. Throughout the years, different methods have been developed in order to mitigate the
The amount of flaky and elongated aggregates in the concrete must be equal to or less than 35% of the total amount of aggregates in the concrete. To allow for better compaction and a higher density of concrete, 20 mm and 10 mm aggregates should be mixed in a 70:30 or 60:40
A method of controlling thermal crack for mass concrete structures: modelling and experimental study. Hong-Ha Le 1, Chi-Cong Vu 1, The control of the concrete temperature to prevent cracking can be viewed as principal goal in the design and construction of mass concrete. This paper researched on a novel technique for
where: ST M = Setting time of cement paste with different molasses range.ST C = Setting time of control cement paste.. Slump test prescribed by ASTM C 143-10 [] was used to determine the workability of four concrete samples prepared with molasses dosage of 0.0%, 0.05%, 0.075%, and 0.1% of the weight of cement.The concrete sample was
Recycled concrete (Source: YouTube/ERC-TECH EU) Methods of Recycling Concrete. The equipment used for crushing the concrete rubble generally consists of a rubble crusher, side discharge conveyor, screening plant and a return conveyor from the screen to the crusher inlet. The return conveyor sends back the oversized materials or the other
Generally speaking, the concrete mixes with the lowest total water content achieved the highest strengths. The mix with fly ash and the highest amount of superplasticizer achieved the highest strength. (sample 7) Concrete with stone aggregates performed much better than mixes with gravel aggregates. Ternary mixes displayed higher concrete
This paper examines how the high-volume replacement of ground granulated blast furnace slag (GGBFS), one of the most widely used mineral admixtures for concrete production, affects the mechanical and heat of hydration characteristics of concrete through both laboratory and mock-up tests. Mechanical properties such as compressive strength,
The amount of air in the mix may be the hardest to control out of all these things. Having air in concrete is important to keep projects inside and out from going wrong. The amount of concrete in the container will stay the same size. The amount of air in concrete is directly linked to how much the pressure in the high-pressure chamber
Method: A core drill is used to extract hardened concrete from the slab. These samples are then compressed in a machine to monitor the strength of the in-situ
The amount of work accomplished using these methods depends on the hammer size, strength of the concrete, the amount of steel reinforcing used in the concrete, and working conditions. Machine-mounted breakers are able to deliver a range of 100 to 20,000 foot-pounds at 300 to 800 blows per minute. Machine-mounted breakers may
At 17 weeks it was 0.041% versus 0.037% for the control mix. Including a non-chloride accelerator (NCA) resulted in twice the amount of shrinkage. At 17 weeks it was 0.064%. A mix with HRWR had the highest shrinkage, but when the amount of cementitious material and water was reduced, the amount of shrinkage decreased
Fogging, or fog spraying, is effective in reducing the chances of plastic shrinkage cracking in mixes with low rates of bleeding. It can also make the difference between success and failure in controlling evaporation between placing and curing the concrete. To fully appreciate what a powerful technique fogging is and how important it can be, we have to
