Length change data underlying the publication: Creep in carbonatable binders: Investigating non-hydraulic lime mortars

<strong>CONTEXT:</strong>This dataset provides the experimentally measured <strong>length change strains of air lime-containing mortars</strong>. The objective was to study the role of carbonation and curing conditions in volume stability and to generate reproducible long-term length change data that can be used to support the calculation of total creep in non-hydraulic binders, such as air lime.<br><strong>GROUPS &amp; MATERIALS:</strong>Mortars were prepared with four binder compositions—<strong>C100L0, C50L50, C33L67, and C0L100</strong>—representing varying proportions of Portland cement (CEM II/A-L 32.5R) and air lime (CL90-S). The number after <strong>'C'</strong> indicates the cement content (binder volume %), while the number after <strong>'L'</strong> indicates the air lime content. For example, C33L67 means that 33 % of the binder is Portland cement and 67 % is air lime. Standard siliceous sand (0–2 mm, EN 196-1:2016) and tap water were used. Specimens were cured under three different regimes <strong>(Curing regimes A, B, and C)</strong> and monitored for length change for up to 240 days.<br><strong>PRODUCTION OF SPECIMENS:</strong>To ensure comparability across all mixtures, the flow diameter was fixed at (164 ± 7) mm, as specified in <strong>EN 459-2:2021</strong>. A consistent mixing procedure was adopted: in total, four minutes of mixing, followed by casting in two layers. Each layer was compacted by mechanical vibration for 30 seconds, in accordance with <strong>EN 459-2:2021</strong> and <strong>EN 196-1:2016</strong>.<br><strong>CURING CONDITIONS:</strong>After initial curing for 7 days in a humid chamber at (95 ± 5) % RH and (21 ± 2) °C (<strong>EN 1015-11:2019</strong>), specimens were subjected to three curing regimes:<strong>Curing regime A</strong>: at natural atmospheric conditions (~0.04 % CO₂), until reaching 28 days.<strong>Curing regime B</strong>: at natural atmospheric conditions (~0.04 % CO₂), until reaching 91 days.<strong>Curing regime C</strong>: in an accelerated carbonation chamber (1 % CO₂), until reaching 28 days.Throughout curing and testing, all groups were maintained at (21 ± 2) °C and (55 ± 5) %. Except for C100L0 (Curing regime A), which was kept at (95 ± 5) % RH, (21 ± 2) °C, and (~0.04 % CO₂) until reaching 28 days, in accordance with <strong>EN 1015-11:2019</strong>.<br><strong>TESTING PROTOCOL:</strong>Length change was measured in accordance with EN 12390-16:2019:<strong>Monitoring duration</strong>: 56 days (Curing regime A) and 240 days (Treatments B and C).<strong>Specimens</strong>: two prisms (10 × 10 × 40 cm) per group per curing regime, providing four measurement points per group in each curing regime.<strong>Measurement</strong>: manual readings with dial gauges (± 0.001 mm) at the intervals recommended by <strong>EN 12390-16:2019</strong>.<strong>Adjustment</strong>: Apart from the identification of outliers, no post-processing, normalization, or fitting has been applied.<strong>Strain calculation</strong>: based on a 20 cm gauge length.<br><strong>VALUE OF THE DATA:</strong>This dataset provides long-term length change strain measurements (up to 240 days) for air lime-containing mortars under three well-defined curing regimes (A, B, and C). It enables analysis of how binder composition and curing environment influence expansion, shrinkage, and overall volume stability. The dataset is valuable for:Assessing the suitability of <strong>EN 12390-16</strong> for non-hydraulic binders.Comparing accelerated and natural carbonation in relation to length change.Supporting model development and calibration for shrinkage/expansion prediction in lime-rich mortars.Complementing the total strain dataset by providing the free length change component under identical curing conditions.Contributing reproducible evidence to both conservation practice and sustainable construction research.

**背景：** 本数据集提供了含气硬性石灰（air lime）的砂浆经实验测得的长度变化应变数据。本研究旨在探究碳化作用与养护条件对体积稳定性的影响，并生成可复现的长期长度变化数据，用于辅助计算气硬性胶凝材料（如气硬性石灰）的总蠕变。
**组分配方与材料：** 本次实验制备了四种胶凝材料配比的砂浆——C100L0、C50L50、C33L67及C0L100，其分别代表波特兰水泥（Portland cement，CEM II/A-L 32.5R）与气硬性石灰（CL90-S）的不同掺量比例。其中，字母‘C’后的数字代表水泥占胶凝材料的体积百分比，字母‘L’后的数字代表气硬性石灰的占比。例如，C33L67表示胶凝材料中33%为波特兰水泥，67%为气硬性石灰。实验采用标准硅质砂（0~2 mm，符合EN 196-1:2016标准）与自来水作为原料。所有试样分别在三种养护制度（养护制度A、B、C）下进行养护，并对其长度变化进行最长达240天的监测。
**试样制备：** 为保证各组砂浆的可比性，根据EN 459-2:2021标准要求，将砂浆的流动直径固定为(164±7) mm。实验采用统一的搅拌流程：总搅拌时长为4分钟，随后分两层浇筑。每层均通过机械振动压实30秒，操作符合EN 459-2:2021与EN 196-1:2016标准的要求。
**养护条件：** 试样先在(95±5)% 相对湿度（RH）、(21±2)℃的潮湿养护箱中进行7天初始养护（符合EN 1015-11:2019标准），随后分别采用三种养护制度处理：
- **养护制度A**：在自然大气环境（约0.04% CO₂）中养护至28天龄期。
- **养护制度B**：在自然大气环境（约0.04% CO₂）中养护至91天龄期。
- **养护制度C**：在加速碳化养护箱（1% CO₂）中养护至28天龄期。
整个养护与测试过程中，所有试样均保持在(21±2)℃、(55±5)% 相对湿度的环境中。唯有C100L0组（养护制度A）除外，该组需按照EN 1015-11:2019标准要求，在(95±5)% 相对湿度（RH）、(21±2)℃及约0.04% CO₂的环境中养护至28天龄期。
**测试规程：** 长度变化的测量依据EN 12390-16:2019标准执行：
- **监测时长**：养护制度A对应的试样监测时长为56天，养护制度B与C对应的试样监测时长为240天。
- **试样规格**：每组养护制度下设置两个棱柱形试样（10×10×40 cm），即每组养护制度下可获得四个测量点数据。
- **测量方式**：采用分度值为±0.001 mm的千分表进行手动读数，读数间隔遵循EN 12390-16:2019标准的推荐要求。
- **数据校正**：除异常值识别外，未对数据进行任何后处理、归一化或拟合操作。
- **应变计算**：基于20 cm的标距长度进行应变计算。
**数据集价值：** 本数据集提供了三种明确养护制度（A、B、C）下，含气硬性石灰的砂浆的长期长度变化应变测量数据（最长达240天）。该数据集可用于分析胶凝材料配比与养护环境对膨胀、收缩及整体体积稳定性的影响。本数据集的应用场景包括：
1. 评估EN 12390-16标准对非水硬性胶凝材料的适用性；
2. 对比自然碳化与加速碳化对长度变化的影响；
3. 辅助富石灰砂浆收缩/膨胀预测模型的开发与校准；
4. 补充总应变数据集，提供相同养护条件下的自由长度变化分量；
5. 为文物保护实践与可持续建筑研究提供可复现的实证数据。