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What is the effect of coarse aggregate size in compressive strength of concrete?
CB Sowmya
As the course aggregate size increases, the compressive stress decreases. It is due to the Interfacial transition zone. The interfacial transition zone exists between the coarse aggregates and the mortar. When concrete is prepared, the water present in the mix forms a film around the aggregate. TheRead more
As the course aggregate size increases, the compressive stress decreases.
It is due to the Interfacial transition zone.
The interfacial transition zone exists between the coarse aggregates and the mortar. When concrete is prepared, the water present in the mix forms a film around the aggregate. The film of water causes a relatively high-water cement ratio in the vicinity of the aggregates. This high water-cement ratio affects the hydration reaction by producing a porous network of Calcium Hydroxide and Ettringite. However, as the hydration reaction proceeds, the second generation of ettringite and calcium hydroxide along with the C-S-H gel starts filling this porous network.
As the size of the aggregate increases, the surface area of the aggregate increases, as a result, the size of the Interfacial Transition Zone also increases. Interfacial Transition Zone reduces the strength of the concrete by producing weaker sections and micro cracks. Therefore, as the size of the aggregate increases, the strength of the concrete reduces.
See lessWhat is punching shear failure of foundation?
CB Sowmya
Punching shear failure of foundation occurs when there is a localized force acting on the structure. It is mostly found in foundations but also common in flat slabs. In punching failure of foundations, the column breaks through the foundation mat. In flat slabs, the failure occurs at the column headRead more
Punching shear failure of foundation occurs when there is a localized force acting on the structure. It is mostly found in foundations but also common in flat slabs.
In punching failure of foundations, the column breaks through the foundation mat. In flat slabs, the failure occurs at the column head. This type of failure is sudden and does not show any warning. Therefore it is crucial to check for punching shear and to provide sufficient reinforcement to take care of it. Reinforcements should be provided in addition to the main reinforcements. This punching shear must not be neglected though it is less critical than the beam shear.
To know more about punching shear,
https://theconstructor.org/structural-engg/punching-shear-slabs-foundations/17716/
See lessWhich method gives accurate desired strength in RCC?
CB Sowmya
Weigh batching gives the desired strength to concrete. There are many reasons for it. First of all, volume batching is an approximate process. It doesn't take into account the voids that will be present when the volume is measured. Bulking of sand can not be corrected in this method. This leads to aRead more
Weigh batching gives the desired strength to concrete. There are many reasons for it.
First of all, volume batching is an approximate process.
More about the process and comparison of volume and weigh batching can be found here
https://theconstructor.org/concrete/concrete-batching-methods/26514/
Thank you!
See lessWhat are the impurities added while manufacturing steel?
CB Sowmya
The impurities added are as follows Carbon - To increase yield strength, ultimate strength and hardness Manganese - To increase yield strength, ultimate strength and hardness Silicon - To increase yield strength, ultimate strength and hardness Copper - To increase yield strength, ultimate strength,Read more
The impurities added are as follows
See lessWhat is membrane curing of concrete?
CB Sowmya
The water added to the concrete according to the mix design is well and enough for the complete hydration of the concrete. But due to the loss of moisture and excess heat of hydration, water is lost. To compensate for this water loss, we go for curing. Membrane curing is a type of curing used for hiRead more
The water added to the concrete according to the mix design is well and enough for the complete hydration of the concrete. But due to the loss of moisture and excess heat of hydration, water is lost. To compensate for this water loss, we go for curing.
Membrane curing is a type of curing used for highway projects, bridges, etc.
In this, a thin membrane is applied on to the surface of the concrete. This membrane inhibits the loss of moisture, thus sealing all the water in the concrete within the layer. This layer serves its purpose until the end of the curing period, i.e., 28 days. Therefore there is no need to monitor the concrete during the curing period continuously. In addition to this, most of the membranes have a reflective property that would reflect the sunlight and thus keeping the surface and beneath cool.
This membrane retains about 95% of the moisture of the concrete.
Various curing membranes include
For more about curing compounds,
https://theconstructor.org/concrete/concrete-curing-compound-types/13478/
See lessWhich type of force acting on water tank wall ?
CB Sowmya
When the tank is on the ground Water pressure acts on the tank walls when the tank is full When the tank is below the ground, When the tank is full, the resultant of the soil and water pressure acts on the tank wall When the tank is empty, the soil pressure alone acts on the wall.
When the tank is on the ground
When the tank is below the ground,
- When the tank is full, the resultant of the soil and water pressure acts on the tank wall
- When the tank is empty, the soil pressure alone acts on the wall.
See lessHow will Poison’s Ratio of a material affect its Strength?
CB Sowmya
Poison's ratio is the ratio of lateral strain to longitudinal strain. It is the property of elasticity of a material. This means that, if a force is applied in a given direction, say along the axis of the member, then the poison's ratio is the ratio of the strain in the direction perpendicular to thRead more
Poison’s ratio is the ratio of lateral strain to longitudinal strain. It is the property of elasticity of a material.
This means that, if a force is applied in a given direction, say along the axis of the member, then the poison’s ratio is the ratio of the strain in the direction perpendicular to the axis and the strain along the axis.
The poison’s ratio of concrete is 0.1 to 0.2. Let’s take that it as 0.15. If a force is applied on a concrete specimen along its axis, then, for every 1 unit of deformation in the axis, 0.15 unit of deformation happens in the perpendicular direction.
Poison’s ratio is a measure of the elastic property of a material. There isn’t any direct relation between the strength of the material and the poison’s ratio.
See lessWhy construction joints are not provided in residential buildings?
CB Sowmya
Construction joints are provided When the day's work comes to an end When there hasn't been enough fresh concrete When the concrete member is tall, i.e, IS 456 restricts the free fall of concrete to 1.2 m. This means that if a column is concreted, the form works are placed only to a height of 1.2m sRead more
Construction joints are provided
Construction joints should be avoided whenever possible. Monolithically cast sections perform better than sections with joints.
The reason why we don’t see construction joints in typical residential buildings is because
Construction joints are found in columns, but they may not be prominent because of the workmanship. Columns are generally cast in stages to a height of 1.2 m each time. Between each session, bond is ensured by providing a rough surface on the older section. This ensures the bond between the new layer and the old layer.
See less