Construction Precast Development
Precast News From China
precast technology developments
Hello everyone, engineering colleagues! Many newcomers and novices who have just entered the construction site feel like they are reading a “heavenly book” from an alien world when faced with the unfolded concrete structure construction drawings? The densely packed lines, symbols, codes, and plain markings are like a string of mysterious codes.
.
.
are they unreadable and difficult to read?.
The shortcomings of this approach: the welding points of the beam stirrups should be set at the top or bottom, and should avoid bending by no less than 100mm.
If the stirrups are bent in advance, they cannot penetrate the original structural floor slab; If the hoop reinforcement penetrates the floor slab and bends on site first, it is difficult to operate in practice and the bending quality cannot be guaranteed.
Therefore, placing the hoop reinforcement welding points on the side of the beam is actually a location with greater stress.
In addition, when using lap welding, the diameter of the hoop reinforcement should not be less than 10mm.
This practice is for reference only.
.
In Xi’an, fire safety is crucial, and as a key facility to ensure fire safety, the quality and reliability of concrete fire water tanks directly affect people’s life and property safety.
So, which concrete fire water pool with outstanding reputation in Xi’an is reliable? Next, let’s delve deeper together.
.
A certain mixing plant, with the same strength of C35, used river sand on Monday and replaced it with machine-made sand on Wednesday.
The result is:.
A certain mixing plant, with the same strength of C35, used river sand on Monday and replaced it with machine-made sand on Wednesday.
The result is:.
The proportion of particles of different sizes in the aggregate is called the gradation of the aggregate.
.
The cracks generated in concrete structures under load are called stress cracks.
Ordinary concrete components may experience stress cracks when subjected to 30% to 40% of the design load, and the ultimate failure load of such components is often more than 1.
5 times the design load value.
As long as the width of such cracks meets the specifications, it will not affect the safety of the structure.
.
In the current mix proportion design specifications in China, JGJ55-2011 “Code for Design of Ordinary Concrete Mix Proportion” is one of the commonly used mix proportion design methods.
In JGJ55-2011 “Code for Design of Ordinary Concrete Mix Proportion”, the basic ideas and parameters of ordinary concrete mix proportion design are specified.
This code is based on the statistical results of a large number of experiments and uses the Baum formula (i.
e.
water cement ratio rule) to design the mix proportion of concrete.
Therefore, this code is applicable to the design of ordinary concrete mix proportion.
For special concrete and high-strength concrete, it is emphasized that based on experience, appropriate materials and mix proportions must be selected through multiple repeated tests using the materials used in the project.
.
Professor An Xuehui from Tsinghua University and Professor Li Pengfei’s team from Chongqing Jiaotong University have completed systematic experimental research in the field of underwater 3D printed concrete.
Together, they have successfully developed underwater self-protection 3D printed concrete technology, which effectively solves industry problems such as easy dispersion, poor molding, and weak interlayer bonding of underwater concrete by innovatively introducing external protection mechanisms for water bodies.
.
The absence of stone slurry will significantly weaken the strength, durability, and overall structural performance of concrete, which is a key defect in concrete quality control.
The specific impacts are as follows:.