Precast News From China
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.
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”.
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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.
), 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:.
1.
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.
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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.
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.
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.
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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When the “Work Plan for Stable Growth in the Building Materials Industry (2025-2026)” jointly issued by the Ministry of Industry and Information Technology and six other departments was officially implemented, the concrete industry, which was once mired in overcapacity, received strong policy stimulus.
The triple focus of “expanding demand, optimizing supply, and strengthening innovation” in the plan is activating the market from multiple dimensions such as infrastructure, urban renewal, and industrial upgrading, ushering in the dawn of demand explosion for the concrete industry with a production capacity utilization rate of less than 25% for two consecutive years.
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Walking in newly built cultural venues, internet famous commercial districts, or high-end residential communities in recent years, you may be attracted by a “special kind of concrete” – it is not covered by heavy paint, with delicate texture patterns on the surface, presenting natural cement colors or a faint warm luster.
It has both the solid texture of concrete and the exquisite sense of design.
This is the highly sought after “plain concrete” in the current design circle, an innovative application that transforms traditional concrete and quietly rewrites the aesthetic expression of architecture and space.
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