Specifications and construction technical problems of concrete construction technology for construct

Since this line of work is done, the "Construction Manual", "Technical Code for Concrete Construction", and "Code for Acceptance of Concrete Construction" are indispensable. It's okay to play with the encyclopedia, but it's not okay to show the real guy.

Teach you a method, let the laboratory take a few more sets of time, under the same conditions of maintenance, each 1 hour to press, and then combined with the specification to reach a few MPA before demolding, winter concrete construction insulation is very important, must pay attention!

Concrete solidification is related to temperature, admixture, concrete strength and water consumption.

The dismantling time should consider the span (more than 8 meters or less), and the location (cantilevered more than 2 meters or less), the size of the component, and whether the bottom mold or the side plate is removed.

In winter construction, we should pay attention to the protection of concrete (to cover and cure, and warm water curing can also be carried out), and to avoid concrete being frozen.

If you have time, you can learn more about the concrete construction acceptance specifications.

Here are a few suggestions for you::

1. Add antifreeze;

2. Raise the concrete grade by one grade;

3. Increase insulation measures, such as mixing with hot water when mixing concrete, covering the concrete surface with straw or other thermal insulation after concrete demoulding, and lighting a fire at night when it is too cold to ensure room temperature;

4. The temperature in Fuyang cannot be so low all the time, it is recommended to stop work for a few days and wait for the weather to be better before construction, because the temperature of the first three days is quite important for concrete, if the temperature of these three days has been below zero, then the concrete will be scrapped.

Answer]: a For the external concrete of the building celery, the relative compactness shall not be less than 98; For the interior concrete, the relative compactness must not be less than 97 dug states.

Answer]: Article 5 of the Code for the Construction Quality of Concrete Structure Engineering (GB50204-2002) (2010 Edition) stipulates that before the strength of the concrete is reached, the formwork and support shall not be stepped on or installed. 【Note】The above content has been deleted in the "Concrete Structure Engineering Construction Quality Acceptance Regulations" (GB50204-2015).

Answer]: A admixture refers to the admixture in the concrete mixture that the infiltration amount exceeds 5% of the cement mass, and the volume or mass change needs to be considered when the mix is designed. Admixtures are active minerals that can not only replace part of the cement to reduce costs, but also improve the performance of concrete.

Reasonable sand rate can make the mixture obtain good fluidity, good cohesion and water retention, and make the cement dosage the most economical; The larger the particle size of the aggregate, the smaller the total surface area per unit volume, and the less cement slurry is required to wrap the aggregate surface, which also saves cement usage. However, they have little effect on the strength of cement.

Summary. Hello dear<>

The answer you're looking for: True. Controlling cracks in concrete is one of the important aspects of concrete structure design, material selection, construction and maintenance.

Design stage: In the design of concrete structures, the mix ratio of concrete should be reasonably determined according to the engineering requirements and use conditions, including controlling the water-cement ratio, selecting appropriate cementitious materials and aggregates, and adding appropriate crack control agents. In addition, the layout and construction of the structure should be reasonably designed to reduce the stress concentration and deformation problems that may occur in the concrete.

Whether the concrete structure should take measures to control concrete cracks from the design, materials, construction and maintenance links is correct.

Is it coming? The concrete structure should be judged from the design, materials, construction, and maintenance of each link, and measures to control concrete cracks should be taken.

When the aggregate used for structural concrete mining and collapse has alkaline activity and potential alkali activity, measures should be taken to breed alkali aggregate reaction, and the effectiveness of breeding measures should be verified.

Can you answer that?

Hello dear<>

The answer you're looking for: True. Controlling cracks in concrete is one of the important aspects of concrete structure design, material selection, construction and maintenance.

Design stage: In the design of concrete structure, the mix ratio of concrete should be reasonably determined according to the engineering requirements and use conditions, including controlling the water-cement ratio, selecting appropriate cementitious materials and aggregates for slag closure, and adding appropriate crack control agents. In addition, the layout and structure of the structure should be reasonably designed to reduce the stress concentration and deformation problems that may occur in the concrete.

The second question is correct. If the aggregate litres used in structural coagulation chowsun soil have alkaline activity or potential alkali activity, measures need to be taken to control the alkali aggregate reaction. Alkali aggregate reaction refers to the reaction of alkali metals in aggregate with water and oxygen in concrete to produce alkali solution and cause expansion and cracks in the concrete.

Answer] :d This question examines RCC construction. For the external concrete of the building, the relative compactness shall not be less than 98; For the internal concrete, the relative dense and slippery air solidity shall not be less than 97.

Answer] :d This question examines RCC construction. For the external concrete of the cavity and slow construction of the cherry blossom round laughing object, the relative compactness shall not be less than 98%; For internal concrete, the relative compactness shall not be less than 97%.