水泥穩(wěn)定碎石底基層和基層是道路工程中常用的半剛性基層結(jié)構(gòu)層，具有強度高、水穩(wěn)性好、承載能力強等優(yōu)點，廣泛應(yīng)用于高速公路、一級公路及城市道路建設(shè)中。以下從施工準(zhǔn)備、材料要求、配合比設(shè)計、施工工藝、質(zhì)量控制及注意事項等方面進行詳細闡述：

Cement stabilized macadam subbase and base are commonly used semi-rigid base structural layers in road engineering, which have the advantages of high strength, good water stability, strong bearing capacity, etc., and are widely used in highway, first-class highway and urban road construction. The following provides a detailed explanation from the aspects of construction preparation, material requirements, mix design, construction technology, quality control, and precautions:

一、定義與用途

1、 Definition and purpose

水泥穩(wěn)定碎石底基層：位于路基與基層之間，主要起承重和擴散荷載的作用，同時改善路基濕度狀況。

Cement stabilized crushed stone subbase: located between the roadbed and the base, it mainly plays a role in bearing and diffusing loads, while improving the humidity condition of the roadbed.

水泥穩(wěn)定碎石基層：直接位于面層下方，是道路結(jié)構(gòu)的主要承重層，承受車輛荷載的反復(fù)作用。

Cement stabilized crushed stone base: directly located below the surface layer, it is the main load-bearing layer of the road structure, bearing the repeated effects of vehicle loads.

二、施工流程

2、 Construction process

1. 施工準(zhǔn)備

1. Construction preparation

下承層驗收：對路基或底基層進行標(biāo)高、寬度、平整度、壓實度等檢測，確保符合設(shè)計要求。

Underpass acceptance: Conduct elevation, width, flatness, compaction, and other inspections on the roadbed or subgrade to ensure compliance with design requirements.

測量放樣：恢復(fù)中線，每10m設(shè)一樁，進行水平標(biāo)高測量，標(biāo)出基層邊緣設(shè)計高。

Measurement and layout: restore the centerline, set up a pile every 10 meters, measure the horizontal elevation, and mark the design height of the base edge.

試驗段鋪筑：通過試驗段確定松鋪系數(shù)、壓實機械組合、碾壓遍數(shù)及含水量控制范圍。

Experimental section paving: Determine the loose paving coefficient, compaction machinery combination, rolling times, and moisture content control range through the experimental section.

2. 材料準(zhǔn)備

2. Material preparation

水泥：選用普通硅酸鹽水泥、礦渣硅酸鹽水泥或火山灰質(zhì)硅酸鹽水泥，強度等級不低于32.5級，初凝時間3小時以上，終凝時間6小時以上。

Cement: Ordinary Portland cement, slag Portland cement or volcanic ash Portland cement shall be selected, with a strength grade of not less than 32.5, an initial setting time of more than 3 hours, and a final setting time of more than 6 hours.

碎石：級配應(yīng)符合規(guī)范要求，最大粒徑不超過31.5mm（基層）或37.5mm（底基層），針片狀含量≤15%，壓碎值≤30%。

Crushed stone: The grading should meet the requirements of the specifications, with a maximum particle size not exceeding 31.5mm (base layer) or 37.5mm (sub base layer), a needle like content of ≤ 15%, and a crushing value of ≤ 30%.

水：清潔、不含有害雜質(zhì)。

Water: clean and free of harmful impurities.

3. 混合料拌和

3. Mixing of mixtures

廠拌設(shè)備：采用穩(wěn)定土拌和站集中拌和，確保配料準(zhǔn)確、均勻。

Factory mixing equipment: Stable soil mixing station is used for centralized mixing to ensure accurate and uniform batching.

含水量控制：根據(jù)天氣、運距調(diào)整含水量，一般比最佳含水量高1%-2%。

Moisture content control: Adjust the moisture content according to weather and transportation distance, generally 1% -2% higher than the optimal moisture content.

水泥劑量控制：通過電子計量裝置精確控制，誤差不超過±0.5%。

Cement dosage control: precise control through electronic measuring devices, with an error not exceeding ± 0.5%.

4. 運輸與攤鋪

4. Transportation and paving

運輸車輛：覆蓋篷布防水分蒸發(fā)，減少混合料離析。

Transport vehicles: covered with tarpaulin to prevent evaporation and reduce segregation of the mixture.

攤鋪機：采用攤鋪機梯隊作業(yè)，保持連續(xù)、均勻攤鋪，速度控制在1.5-2.5m/min。

Paver: The paver operates in a staggered manner to maintain continuous and even paving, with a speed controlled between 1.5-2.5m/min.

松鋪系數(shù)：通過試驗段確定，一般為1.25-1.35。

Loose laying coefficient: determined through experimental sections, generally ranging from 1.25-1.35.

5. 碾壓

5. Rolling

壓路機組合：初壓（靜壓）→復(fù)壓（振動碾壓）→終壓（靜壓），總遍數(shù)不少于6-8遍。

Roller combination: initial compaction (static pressure) → re compaction (vibration compaction) → final compaction (static pressure), with a total of no less than 6-8 passes.

碾壓順序：從低到高，先輕后重，先慢后快，輪跡重疊1/2輪寬。

Rolling sequence: from low to high, light to heavy, slow to fast, overlapping wheel tracks by 1/2 wheel width.

壓實度要求：基層≥98%，底基層≥97%（重型擊實標(biāo)準(zhǔn)）。

Compaction requirements: Base layer ≥ 98%, sub base layer ≥ 97% (heavy compaction standard).

6. 養(yǎng)生與交通管制

6. Health Preservation and Traffic Control

養(yǎng)生方式：采用土工布覆蓋灑水養(yǎng)生，保持表面濕潤，養(yǎng)生期7-14天。

Health preservation method: Use geotextile to cover and sprinkle water for health preservation, keep the surface moist, and the health preservation period is 7-14 days.

交通管制：養(yǎng)生期間禁止車輛通行，達到設(shè)計強度后開放交通。

Traffic control: Vehicles are prohibited from passing during the health period, and traffic will be opened after reaching the design intensity.

三、質(zhì)量控制要點

3、 Key points of quality control

1. 材料質(zhì)量控制

1. Material quality control

水泥：進場檢驗強度、安定性、凝結(jié)時間。

Cement: Inspection of strength, stability, and setting time upon arrival.

碎石：檢測級配、壓碎值、針片狀含量。

Gravel: Testing grading, crushing value, and needle like content.

混合料：抽檢水泥劑量、含水量、級配。

Mixture: Sampling inspection of cement dosage, moisture content, and gradation.

2. 施工過程控制攤鋪：連續(xù)作業(yè)，減少縱向接縫，橫向接縫垂直相接。

2. Construction process control paving: continuous operation, reducing longitudinal joints, and connecting transverse joints vertically.

碾壓：在最佳含水量±2%范圍內(nèi)碾壓，避免過振或漏振。

Rolling: Rolling within the optimal moisture content range of ± 2% to avoid excessive or missed vibration.

平整度：通過3m直尺檢測，誤差≤12mm（基層）、≤15mm（底基層）。

Flatness: Tested with a 3m ruler, with an error of ≤ 12mm (base layer) and ≤ 15mm (sub base layer).

3. 強度檢測

3. Strength testing

無側(cè)限抗壓強度：基層≥3-5MPa（7天），底基層≥2-4MPa（7天），具體值按設(shè)計要求。

Unconfined compressive strength: base layer ≥ 3-5 MPa (7 days), sub base layer ≥ 2-4 MPa (7 days), specific values according to design requirements.

四、常見問題及預(yù)防措施

4、 Common problems and preventive measures

裂縫：控制水泥劑量（≤5%），加強養(yǎng)生，避免早期失水。

Cracks: Control the cement dosage (≤ 5%), strengthen health preservation, and avoid early dehydration.

離析：控制集料級配，減少運輸、攤鋪過程中的落差。

Segregation: Control the gradation of aggregates to reduce the drop during transportation and paving processes.

壓實度不足確保含水量適宜，增加碾壓遍數(shù)，避免漏壓。

Insufficient compaction ensures appropriate moisture content, increases the number of rolling passes, and avoids missed compaction.

五、安全與環(huán)保措施

5、 Safety and environmental protection measures

安全：設(shè)置警示標(biāo)志，施工人員穿戴防護用品，機械操作專人指揮。

Safety: Warning signs should be set up, construction personnel should wear protective equipment, and machinery operators should be directed by a dedicated person.

環(huán)保：控制揚塵，廢料集中處理，避免污染水源。

Environmental Protection: Control dust, centralize waste disposal, and avoid polluting water sources.

六、總結(jié)

6、 Summary

水泥穩(wěn)定碎石底基層和基層施工需嚴(yán)格把控材料質(zhì)量、配合比設(shè)計、施工工藝及養(yǎng)生等環(huán)節(jié)，通過精細化管理和科學(xué)檢測，確?；鶎訌姸?、平整度及耐久性，為道路工程提供穩(wěn)定、可靠的承重結(jié)構(gòu)。

The construction of cement stabilized crushed stone subbase and base requires strict control over material quality, mix design, construction technology, and curing. Through refined management and scientific testing, the strength, flatness, and durability of the base are ensured, providing a stable and reliable load-bearing structure for road engineering.

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