LC5.0Lightweight aggregate concrete: the preferred solution for lightweight and energy-saving building materials

1、 Definition and Overview

LC5.0Lightweight aggregate concrete isThe strength level is5.0MPa(Standard value of compressive strength of cube)≥5.0MPa）Lightweight aggregate concrete belongs to the low strength category of lightweight aggregate concrete. Its core feature isLow apparent density(Usually)800-1200kg/m³, only for ordinary concrete40%-60%）AndExcellent thermal insulation performanceIt is mainly used for non structural or secondary structural parts in construction projects, such as wall filling, roof insulation, prefabricated lightweight components, etc. It is a key material for achieving building energy efficiency and lightweighting.

2、 Composition of raw materials

LC5.0The raw materials for lightweight aggregate concrete need to balance lightweight, workability, and cost, mainly including the following categories:

1. lightweight aggregateAs a skeleton material, it is the core component that reduces the self weight of concrete. Common types includeceramsite(Shale ceramic particles, fly ash ceramic particles, apparent density)300-800kg/m³）The(apparent density)80-200kg/m³）Theslag(apparent density)400-600kg/m³）Wait. Among them, fly ash ceramic particles are prepared using industrial waste (fly ash), which meets the requirements of circular economy,.

2. cementitious materialUsing ordinary Portland cement（P·O 32.5or42.5Mainly composed of (grade), can be mixed infly ash(Replace)10%-30%Cement)slag powder(Replace)20%-40%Admixtures such as cement can reduce costs and improve the workability of concrete, such as fly ash“Ball effect”）At the same time, increase the intensity in the later stage.

3. fine aggregate: OptionalLight sand(such as sand, pottery sand) orOrdinary sand(River sand, machine-made sand), but it is necessary to control the grading of fine aggregates (such as fineness modulus)2.0-3.0）To avoid poor fluidity or layering of concrete caused by poor grading.

4. admixtureTo adjust the performance of concrete, it is necessary to addwater-reducing admixture(such as polycarboxylate superplasticizer, dosage)0.5%-1.0%）Improve liquidity,air-entraining agent(dosage)0.01%-0.03%）Improve frost resistance,water-retaining agent(such as cellulose ether, dosage)0.05%-0.1%）Prevent rapid loss of slump (as lightweight aggregates are prone to water absorption).

3、 Key points of preparation process

LC5.0The preparation of lightweight aggregate concrete needs to be addressedFloating of lightweight aggregate(Due to its much lower density than cement slurry) andIntensity uniformityThe key process is as follows:

1. Mix Proportion Design: AdoptingVolume methodBased on the target apparent density (such as1000kg/m³）Calculate the volume of each component: volume of lightweight aggregate=Concrete volume×Volume fraction of lightweight aggregate (generally)30%-50%）Volume of cement slurry=Concrete volume-Volume of lightweight aggregate-Volume of fine aggregate. Need to be adjusted through trial mixing to ensure slump（50-100mm）Meet the construction requirements while ensuring that the strength meets the standard.

2. Pre wetting of lightweight aggregateSoak the lightweight aggregate before mixing2-4Hours (or pre wetting with water spray) should be used to saturate the surface but not absorb water internally, in order to avoid absorbing moisture from the cement slurry during mixing and causing a sharp decrease in slump.

3. Mixing process: AdoptingStep-by-step mixing methodFirst, mix the lightweight aggregate with some water1-2Minute (to disperse light aggregate), then add cement, admixtures, and fine aggregate and stir2-3Minutes, finally add the admixture and stir with the remaining water1-2minute. Avoid excessive mixing (to prevent crushing of lightweight aggregates) and ensure uniformity of the mixture.

4. Forming and maintenance: AdoptingVibration molding(Vibration time)10-20To avoid the floating and layering of lightweight aggregates in seconds; Cover with plastic film after molding,Moisturizing maintenance7-14skyDue to the good water retention of lightweight aggregates, but sufficient moisture is required for early cement hydration, insulation measures such as covering with cotton quilts should be taken in winter.

4、 Core performance advantages

LC5.0The performance advantages of lightweight aggregate concrete directly correspond to its application value:

1. Lightweight properties: apparent density800-1200kg/m³, can reduce the load on building structures20%-40%Reduce the cost of foundation treatment (especially suitable for weak foundations).

2. Thermal insulation propertiesThermal conductivity coefficient0.18-0.35W/Ordinary concrete is1.5-2.0W/）When used for walls, it can reduce the heat transfer coefficient30%-50%Meet the General Code for Building Energy Efficiency and Renewable Energy Utilization（GB 55015-2021）Energy saving requirements (such as heat transfer coefficient of walls in northern regions)≤0.60W/）.

3. Sound insulation performanceDue to the porous interior of lightweight aggregates, the air layer can effectively absorb sound,100mmthickLC5.0The air sound insulation of the wall can reach40-45dBOrdinary concrete walls are30-35dB）Meet the sound insulation requirements of residential buildings.

4. fire resistanceLightweight aggregate (such as ceramic particles) with high temperature resistance（1000℃The above does not deform. Concrete structures heat up slowly and deform less in a fire,100mmthickLC5.0The fire resistance limit of the wall can reach2-3Hour (for ordinary concrete)1-1.5Hour).

5. durabilityBy using reasonable mix proportions (such as air entraining agents and water reducing agents), it is possible to meet the requirements of impermeability (impermeability level)P6）Frost resistance (frost resistance level)F150）Requirement, suitable for humid or cold environments.

5、 Main application areas

LC5.0Lightweight aggregate concrete is widely used in the following scenarios due to its strong performance adaptability:

1. ** residentialbuilding**As:Fill wall materials(such as lightweight blocks and wall panels), reducing floor load while improving indoor insulation effect (such as partition walls in northern regions); asRoof insulation layer(Laying)100-150mmThick), replacing traditional insulation materials such as polystyrene board, to avoid fire hazards.

2. industrial building: Used forfirewall(Utilizing fire resistance)Workshop roof insulation layer(such as steel plants, chemical plants)Equipment foundation cushion layer(Reduce equipment vibration transmission).

3. prefabricated component: ProductionLightweight staircase、Lightweight balcony panel、lightweight partition panelWaiting for prefabricated components to reduce transportation and installation costs30%-50%Due to its light weight, it conforms to the trend of building industrialization.

4. Special Environmental Engineering: Used forCold storage wall(Good insulation to prevent cold bridge effect)High temperature workshop wall(Strong fire resistance, resistant to high temperature radiation)Bridge substructure(Reduce the load on bridge piers and extend the service life of bridges).

6、 Development prospects

withgreen building(such as“carbon peaking and carbon neutrality”Target) andconstruction industrializationThe advancement,LC5.0The development prospects of lightweight aggregate concrete are broad:

1. Raw material upgrade: DevelopmentHigh performance lightweight aggregate(such as high-strength ceramic particles, apparent density)500-700kg/m³, compressive strength≥5MPa）Improve the strength of concrete (such asLC7.5TheLC10）Expand its application to structural parts (such as infill walls in frame structures).

2. process optimization: AdoptingReady mixed concrete(Factory production), improve the accuracy of mix proportion and construction efficiency; promotion3Dprinting technologyBy utilizing the good fluidity and light weight of lightweight aggregate concrete, rapid prototyping of complex shaped components can be achieved.

3. policy support: Country《“the 14th Five-Year Plan”The Development Plan for Building Energy Efficiency and Green Buildings clearly proposes“Promote energy-saving materials such as lightweight aggregate concrete”Various regions have introduced subsidy policies, such as Beijing and Shanghai providing subsidies per square meter for projects using lightweight wall materials50-100Yuan subsidy) to promote its popularization.

In conclusion,LC5.0Lightweight aggregate concrete asLightweight, energy-saving, and environmentally friendlyThe building materials not only solve the problem of traditional concrete“Heavy, clumsy, and high energy consumption”The pain points are more in line with the future development trend of architecture and are expected to become a major force in the field of building materials“Mainstream choice”.