NEW HORIZON#38
MAY 2024
31
Collaborating closely with the China Railway Zhuzhou Bridge Co., Ltd. team, Sika's
concrete team has fully supported the
construction of Baiyun Railway Station
project under the guidance of the China
Railway Construction Group's general
contracting construction organization.
This support includes high-durability
concrete technology, high-strength and
high-performance concrete technology,
self-compacting concrete technology,
bare concrete technology, concrete crack
control technology, and ultra-slow setting
concrete technology. All products and
technical solutions have received approval
from the Guangzhou Railway Group's Station Building Construction Headquarters.
As the saying goes, \"a tall building starts
from level ground\", and the steel pipe column system serves as the crucial support
framework for the upward expansion of
Baiyun Railway Station. According to data
from the construction unit, Baiyun Railway Station comprises over 100,000 tons
of complex steel structures, with the concrete steel column structure being a vital
component. Concrete-filled steel columns,
integral to the structure, are formed by
filling concrete into steel pipes and are
fundamental load-bearing elements in
engineering structures, often used as
supports, bridge piers, and foundation columns.
Sika's concrete team assists in the construction of the concrete steel column
structure at Baiyun Railway Station by
providing C70 self-compacting core concrete. This specialized concrete was used
in Phase I and Phase II of the concrete
steel column structure at Baiyun Railway
Station, comprising approximately 1,000
steel columns and a total volume of about
30,000 cubic meters of concrete. The
construction required the C70 concrete to
meet design specifications, ensuring minimal pumping loss (with a pipeline length
of approximately 300 meters), and exhibiting no segregation, bleeding, or color
deviation.
Sika ViscoCrete® 3301C high-performance
polycarboxylic acid admixture solution
addresses engineering challenges such as
poor strength, adhesion, and pumpability.
The concrete raft foundation for pier
footing in Phase I and Phase II of Baiyun
Station adopts C45 shrinkage-compensating concrete, with a maximum thickness
of about 2 meters and a concrete volume
of about 400,000 cubic meters. This constitutes a large-volume concrete structure
with substantial pouring volume and extended pouring duration.
Sika ViscoCrete® 3301C high-performance
polycarboxylic acid admixture solution
is employed in the large raft concrete,
addressing issues such as high concrete
viscosity and low heat of hydration while
effectively controlling the core temperature of the concrete. As a result, upon
formwork removal, the raft foundation
exhibits no cracks or surface shrinkage,
presenting a smooth and aesthetically
pleasing appearance, and has received full
recognition from the Guangzhou Railway
Group's Station Building Construction
Headquarters.
The concrete transition layer structure
in Phase I and Phase II of Baiyun Railway
Station utilizes C0 transition layer concrete, with a concrete volume of approximately 150,000 cubic meters. The project
requires concrete with low hydration heat,
high durability, no bleeding, no efflorescence, no cracks, low shrinkage, strong
pumpability, and minimal surface bubbles.
Faced with challenges such as high concrete grade, high structural thermal conductivity, and long pumping distance (300
meters) during the project construction,
Sika's concrete team has stepped up to
the challenge. It provided a solution using
Sika ViscoCrete® 3301 high-performance
polycarboxylic acid admixture for the
transition layer concrete. This solution
addressed engineering challenges while
effectively controlling the center temperature of the concrete. During construction,
there was no bleeding or segregation, and
after formwork removal, the concrete
showed no cracks with a smooth surface
and minimal air voids.
To facilitate seamless connection with six
subway lines, both Phase I and Phase II
projects at Baiyun Railway Station have
reserved space for subway lines.
For the construction of C50 ultra-slow setting pile concrete, there is limited practical
experience domestically, and each project
has different actual conditions and requirements. In response to this challenge,
Sika's concrete team's technical staff have
been diligently researching and exploring
various quality control key points.
Ultimately, Sika ViscoCrete®-3301C and
Sika Retardol®-25, polycarboxylic acid-based water-reducing and retarding
admixture solutions, provided a reserve of
1,000 cubic meters of super-retarded concrete for the subways, with a retardation
time of 66 hours, fully meeting the project
requirements. The workability of the concrete was excellent, with no segregation,
no bleeding, and the slump retention all
fully meeting the project requirements.
China's vast land encompasses almost all
terrains of human activity, including plains,
plateaus, grasslands, deserts, mountainous areas, and jungles, and also covers all
types of climatic zones. Sika's concrete
team in China fearlessly tackles any challenges and persists in their efforts. To
date, they have made outstanding contributions to the construction of many large
high-speed railway stations in China, such
as Tianjin West Railway Station, Guangzhou South Railway Station, Chongqing
West Railway Station, and Beijing South
Railway Station.
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