precast-tech

The Code for Acceptance of Construction Quality of Concrete Structures GB 50204-2015 is a mandatory national standard for the construction quality of concrete structures in China’s construction engineering field.

It came into effect on September 1, 2015 and replaced the original standard GB 50204-2002 (2011 edition).

Halfen Channel

This specification specifies the construction quality acceptance requirements for concrete structure engineering from raw materials to finished products, ensuring that the structural safety, durability, and functional use of the project meet the design requirements.

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The strength of concrete has a significant impact on the overall service and use in the future.

High strength results in longer service life and correspondingly higher wear and compression resistance; If the strength is too weak, it can easily lead to a series of disadvantages such as sanding, graying, cracking, poor wear resistance, and poor impermeability, requiring significant costs for repair or refurbishment.

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Admixtures have become an indispensable component of concrete and are widely used in concrete production.

However, in production practice, engineering quality accidents often occur due to improper selection and use of admixtures.

Erection Anchor

The negative effects that commonly used additives may have on the performance of concrete mainly include the following aspects:.

In the construction industry, some construction workers often refer to winter construction concrete and concrete with frost resistance requirements in structural design as “frost resistant concrete”.

Shuttering Magnet

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According to the Implementation Rules for Green Building Material Product Certification and the characteristics of concrete products (including pre mixed concrete, special concrete such as permeable concrete, high-performance concrete, etc.

Plastic Nail Plate

), enterprises applying for concrete green building material certification need to prepare the following documents according to the following list to ensure the efficient progress of the certification process:.

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Plastic Rebar Chairs

Localized lack of slurry and roughness on the surface, or numerous small pits, resulting in poor visual quality.

As an important structural form of high-grade highways and urban roads, the design quality of cement concrete pavement directly affects the performance, durability, and driving safety of the pavement.

According to current regulatory requirements, the design of cement concrete pavement is a systematic project that requires comprehensive consideration of various aspects such as surface layer type selection, structural layer combination, joint construction, reinforcement measures, and drainage schemes.

Rebar Wheel Spacers

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Are friends who work on high demand concrete projects often troubled by these problems: after demoulding, the surface of the concrete is pitted, the edges and corners are damaged, and the mirror effect cannot be achieved; Release agent contaminates steel formwork, affecting structural safety; RC1301 concrete demoulding agent can accurately solve the problems of failure when washed away by rain and water, and always causing problems in outdoor construction.

Shuttering Magnet

It is a water-based formula designed specifically for “concrete demolding with high surface requirements”, especially suitable for customers who pursue surface texture and structural safety.

From core requirements to construction adaptation, it is reassuring.

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Cement: Guangdong Qingxin Conch Cement Co.

, Ltd.

P · Ⅱ 52.

5R cement, with a specific surface area of 437m2/kg, meets the requirements of GB175-2007 “General Portland Cement”; Silica fume: SiO2 content of 96.

34%, specific surface area of 19500m2/kg, produced by Gansu Yuyang New Materials Co.

, Ltd.

, meets the requirements of GB/T27690-2011 “Silica fume for mortar and concrete”; Fly ash microbeads: SiO2 content 56.

5%, specific surface area 2431m2/kg, Tianjin Zhucheng Fly Ash microbeads Co.

, Ltd; Fly ash: Grade I, water requirement ratio of 92%, specific surface area of 645m2/kg, loss on ignition of 4%, 28 day activity index of 72%, Shandong Shunke Building Materials Technology Co.

, Ltd; Mineral powder: S95 grade, specific surface area 448m2/kg, alkalinity 0.

Pfeifer VS Box

91, Shandong Changshengyuan Slag Micropowder Co.

, Ltd.

The main chemical components of cementitious materials are shown in Table 1.

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Most of the air entraining agents are anionic surfactants.

At the water vapor interface, the hydrophobic group adsorbs directionally towards the air side.

At the cement water interface, the cement or its hydrated ions adsorb towards the hydrophilic group.

Pfeifer VS Box

The hydrophobic group deviates from the cement and its hydrated ions, forming a hydrophobic adsorption layer and striving to approach the air surface.

Due to the proximity of these ions to the air surface and the adsorption effect of the air entraining agent molecules at the air water interface, the surface tension of water is significantly reduced, resulting in the generation of a large number of fine bubbles in the concrete during the mixing process.

These bubbles carry directional adsorption layers with the same charge, so they repel each other and can be evenly distributed; On the other hand, many anionic air entraining agents have calcium salt precipitation in cement aqueous solutions with high calcium content, which adsorbs onto the bubble membrane and can effectively prevent bubble bursting.

The small and uniform bubbles introduced can exist stably for a certain period of time.

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