一、 工程概況

　　1、 Project Overview

　　本項目為某地區新建一級公路，設計車速80km/h。根據設計要求，路面基層采用厚度為36cm的水泥穩定級配碎石，分兩層施工。為確保基層具有足夠的強度、良好的板體性和耐久性，需進行科學的配合比設計。

　　This project is a new first-class highway in a certain area, with a design speed of 80km/h. According to the design requirements, the pavement base layer is constructed in two layers using cement stabilized graded crushed stone with a thickness of 36cm. To ensure that the grassroots has sufficient strength, good board performance, and durability, scientific mix design is necessary.

　　工程名稱：XX一級公路路面基層工程

　　Project name: XX first-class highway pavement base course project

　　結構層：下基層（18cm）+ 上基層（18cm）

　　Structural layer: Lower base layer (18cm)+Upper base layer (18cm)

　　設計標準：7天無側限抗壓強度 ≥ 4.0 MPa

　　Design standard: 7-day unconfined compressive strength ≥ 4.0 MPa

　　設計依據：

　　Design basis

　　1. 《公路路面基層施工技術細則》（JTG/T F20-2015）

　　1. Technical Guidelines for Construction of Highway Pavement Base (JTG/T F20-2015)

　　2. 《公路工程集料試驗規程》（JTG E42-2005）

　　2. Test Code for Aggregates in Highway Engineering (JTG E42-2005)

　　3. 《公路工程無機結合料穩定材料試驗規程》（JTG E51-2009）

　　3. Test Code for Inorganic Bonding Material Stabilized Materials in Highway Engineering (JTG E51-2009)

　　二、 原材料選擇與檢驗

　　2、 Raw material selection and inspection

　　配合比設計的基石是合格的原材料。我們對工程擬采用的原材料進行了全面檢測。

　　The cornerstone of mix design is qualified raw materials. We have conducted a comprehensive inspection of the raw materials to be used in the project.

　　1. 水泥

　　1. Cement

　　品種與標號：采用P.O 42.5級普通硅酸鹽水泥。

　　Variety and grade: P.O 42.5 grade ordinary Portland cement is used.

　　技術要求：初凝時間應大于3小時，終凝時間應大于6小時且小于10小時，穩定性合格。

　　Technical requirements: The initial setting time should be greater than 3 hours, the final setting time should be greater than 6 hours and less than 10 hours, and the stability should be qualified.

　　檢測結果：經檢測，所選用水泥各項指標均滿足規范要求。

　　Test results: After testing, all indicators of the selected cement meet the specification requirements.

　　2. 碎石

　　2. Gravel

　　料源：本地某石料場生產的石灰巖。

　　Material source: Limestone produced by a local quarry.

　　規格：采用4種規格集料進行摻配：

　　Specifications: Four types of aggregate are used for blending:

　　1#料（19-31.5mm）

　　1 # material (19-31.5mm)

　　2#料（9.5-19mm）

　　Material # 2 (9.5-19mm)

　　3#料（4.75-9.5mm）

　　Material # 3 (4.75-9.5mm)

　　4#料（0-4.75mm）石屑

　　4 # material (0-4.75mm) stone chips

　　技術要求：壓碎值≤28%，針片狀含量≤18%，軟石含量≤5%。

　　Technical requirements: crushing value ≤ 28%, needle like content ≤ 18%, soft stone content ≤ 5%.

　　檢測結果：對各類集料進行檢測，壓碎值為22%，針片狀含量為12%，均滿足規范要求。

　　Test results: Various types of aggregates were tested, with a crushing value of 22% and a needle like content of 12%, all of which meet the specification requirements.

　　3. 水

　　3. Water

　　采用潔凈的飲用水，符合工程用水標準。

　　Using clean drinking water that meets engineering water standards.

　　三、 目標配合比設計

　　3、 Target mix design

　　步驟一：級配設計

　　Step 1: Grading Design

　　根據《JTG/T F20-2015》規范中對水泥穩定碎石基層的級配范圍要求，結合本地材料特性，確定目標級配。

　　According to the grading range requirements for cement stabilized crushed stone base in the JTG/T F20-2015 standard, combined with local material characteristics, the target grading is determined.

　　規范中級配范圍（基層）：

　　Standardize the scope of intermediate configuration (grassroots):

　　合成級配計算：

　　Composite gradation calculation:

　　通過試驗和計算，確定各規格集料的摻配比例。

　　Determine the mixing ratio of each specification of aggregate through experiments and calculations.

　　建議比例：1#料 : 2#料 : 3#料 : 4#料 = 25% : 30% : 20% : 25%

　　Suggested ratio: 1 # material: 2 # material: 3 # material: 4 # material=25%: 30%: 20%: 25%

　　合成后級配：

　　Grading after synthesis:

　　結論：合成級配完全落在規范要求的范圍內，且曲線圓滑，屬于優良級配。

　　Conclusion: The composite grading completely falls within the range required by the specifications, and the curve is smooth, belonging to excellent grading.

　　步驟二：確定最佳含水量和最大干密度

　　Step 2: Determine the optimal moisture content and maximum dry density

　　采用重型擊實試驗法。我們選擇了4個不同的水泥劑量（3.0%, 3.5%, 4.0%, 4.5%）進行試驗。

　　Adopting the heavy compaction test method. We selected four different cement dosages (3.0%, 3.5%, 4.0%, 4.5%) for the experiment.

　　試驗方法：對每種水泥劑量的混合料，配制5-6個不同含水量的試樣進行擊實試驗，繪制含水量-干密度曲線。

　　Test method: For each cement dosage mixture, prepare 5-6 samples with different moisture contents for compaction test, and draw the moisture content dry density curve.

　　試驗結果匯總：

　　Summary of experimental results:

　　規律：隨著水泥劑量的增加，最大干密度略有增大，最佳含水量也相應提高。

　　Rule: With the increase of cement dosage, the maximum dry density slightly increases, and the optimal moisture content also increases accordingly.

　　步驟三：無側限抗壓強度試驗

　　Step 3: Unconfined compressive strength test

　　這是驗證配合比是否滿足設計要求的核心環節。

　　This is the core step in verifying whether the mix proportion meets the design requirements.

　　試件制備：按上述確定的級配、最佳含水量和最大干密度，采用靜壓法成型Φ150mm × 150mm的圓柱體試件，每個水泥劑量制備13個試件（9個用于強度測定，4個備用）。

　　Preparation of test specimens: According to the determined grading, optimal moisture content, and maximum dry density, cylindrical specimens with a diameter of 150mm × 150mm were formed using static pressure method. Thirteen specimens were prepared for each cement dosage (nine for strength determination and four for backup).

　　養護與試驗：試件在標準條件下（20±2°C，濕度≥95%）養護6天，浸水1天后，進行無側限抗壓強度試驗。

　　Maintenance and Testing: The specimen is cured for 6 days under standard conditions (20 ± 2 ° C, humidity ≥ 95%), and then immersed in water for 1 day before undergoing unconfined compressive strength testing.

　　強度結果：

　　Strength results:

　　說明：Rd為設計強度4.0MPa，Zα取1.645（保證率95%），Cv為偏差系數（S/Rc）。

　　Explanation: Rd is the design strength of 4.0MPa, Z α is taken as 1.645 (guarantee rate of 95%), and Cv is the deviation coefficient (S/Rc).

　　步驟四：目標配合比確定

　　Step 4: Determine the target mix ratio

　　經濟與技術性比選：

　　Economic and technological comparison:

　　水泥劑量4.0%時，強度為5.1MPa，滿足設計要求（≥4.0MPa），且有一定富余。

　　When the cement dosage is 4.0%, the strength is 5.1 MPa, which meets the design requirements (≥ 4.0 MPa) and has a certain margin.

　　水泥劑量4.5%時，強度更高，但水泥用量增加，不經濟，且水泥劑量過高易導致干縮裂縫增多。

　　When the cement dosage is 4.5%, the strength is higher, but increasing the cement dosage is uneconomical, and excessive cement dosage can easily lead to an increase in shrinkage cracks.

　　最終確定目標配合比：

　　Final determination of target mix ratio:

　　集料比例： 1#料 : 2#料 : 3#料 : 4#料 = 25 : 30 : 20 : 25

　　Aggregate ratio: 1 # material: 2 # material: 3 # material: 4 # material=25:30:20:25

　　水泥劑量： 4.0% （外摻法，即水泥質量占干集料總質量的百分比）

　　Cement dosage: 4.0% (external mixing method, i.e. the percentage of cement mass to total dry aggregate mass)

　　最大干密度： 2.34 g/cm?

　　Maximum dry density: 2.34 g/cm?

　　最佳含水量： 5.6%

　　Best moisture content: 5.6%

　　四、 生產配合比驗證與施工控制

　　4、 Production mix ratio verification and construction control

　　1. 生產配合比驗證：在目標配合比確定后，應在拌和站進行試拌。對熱料倉的集料進行篩分，調整冷料倉的進料比例，確保生產出的混合料級配與目標級配基本一致。

　　1. Production mix proportion verification: After the target mix proportion is determined, trial mixing should be carried out at the mixing station. Screen the aggregate from the hot material bin, adjust the feeding ratio of the cold material bin, and ensure that the produced mixture has a gradation that is basically consistent with the target gradation.

　　2. 施工控制要點：

　　2. Key points of construction control:

　　含水量控制：施工時混合料的含水量應略高于最佳含水量0.5%~1.0%，以補償運輸和攤鋪過程中的水分損失，通常控制在6.0%~6.5%。

　　Moisture content control: During construction, the moisture content of the mixture should be slightly higher than the optimal moisture content by 0.5% to 1.0% to compensate for moisture loss during transportation and paving, usually controlled at 6.0% to 6.5%.

　　拌和均勻性：確保水泥分布均勻，無灰條、花白料。

　　Uniformity of mixing: Ensure that the cement is evenly distributed without any gray strips or white materials.

　　壓實：及時碾壓，采用合理的壓實工藝（如靜壓+弱振+強振+膠輪收面），確保壓實度達到98%以上。

　　Compaction: Timely compaction, using reasonable compaction techniques (such as static pressure+weak vibration+strong vibration+rubber wheel finishing) to ensure a compaction degree of over 98%.

　　養護：碾壓完成后立即覆蓋土工布或灑水養護，保持表面濕潤，養護期不少于7天。

　　Maintenance: Immediately cover with geotextile or sprinkle water for maintenance after compaction, keep the surface moist, and the maintenance period is not less than 7 days.

　　五、 結論

　　5、 Conclusion

　　通過本實例，我們系統性地完成了水泥穩定級配碎石的配合比設計。最終確定的配合比為：集料比例25:30:20:25，水泥劑量4.0%，最佳含水量5.6%，最大干密度2.34 g/cm?。該配合比不僅滿足了設計強度要求，也兼顧了材料的抗裂性和經濟性，為后續的大規模施工提供了可靠的技術依據。在實際施工中，必須根據原材料波動和天氣情況，對含水量等參數進行動態微調，以確保工程質量萬無一失。

　　Through this example, we systematically completed the mix design of cement stabilized graded crushed stone. The final determined mix ratio is: aggregate ratio of 25:30:20:25, cement dosage of 4.0%, optimal moisture content of 5.6%, and maximum dry density of 2.34 g/cm ??. This mix ratio not only meets the design strength requirements, but also takes into account the material's crack resistance and economy, providing a reliable technical basis for subsequent large-scale construction. In actual construction, it is necessary to dynamically adjust parameters such as moisture content based on fluctuations in raw materials and weather conditions to ensure the quality of the project is foolproof.

　　本文由  濟南水泥穩定碎石 友情奉獻.更多有關的知識請點擊  http://www.dfhun.cn/   真誠的態度.為您提供為全面的服務.更多有關的知識我們將會陸續向大家奉獻.敬請期待.

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