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

CONTEXT:This dataset provides the experimentally measured length change strains of air lime-containing mortars. 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.
GROUPS & MATERIALS:Mortars were prepared with four binder compositions—C100L0, C50L50, C33L67, and C0L100—representing varying proportions of Portland cement (CEM II/A-L 32.5R) and air lime (CL90-S). The number after 'C' indicates the cement content (binder volume %), while the number after 'L' 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 (Curing regimes A, B, and C) and monitored for length change for up to 240 days.
PRODUCTION OF SPECIMENS:To ensure comparability across all mixtures, the flow diameter was fixed at (164 ± 7) mm, as specified in EN 459-2:2021. 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 EN 459-2:2021 and EN 196-1:2016.
CURING CONDITIONS:After initial curing for 7 days in a humid chamber at (95 ± 5) % RH and (21 ± 2) °C (EN 1015-11:2019), specimens were subjected to three curing regimes:Curing regime A: at natural atmospheric conditions (~0.04 % CO₂), until reaching 28 days.Curing regime B: at natural atmospheric conditions (~0.04 % CO₂), until reaching 91 days.Curing regime C: 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 EN 1015-11:2019.
TESTING PROTOCOL:Length change was measured in accordance with EN 12390-16:2019:Monitoring duration: 56 days (Curing regime A) and 240 days (Treatments B and C).Specimens: two prisms (10 × 10 × 40 cm) per group per curing regime, providing four measurement points per group in each curing regime.Measurement: manual readings with dial gauges (± 0.001 mm) at the intervals recommended by EN 12390-16:2019.Adjustment: Apart from the identification of outliers, no post-processing, normalization, or fitting has been applied.Strain calculation: based on a 20 cm gauge length.
VALUE OF THE DATA: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 EN 12390-16 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.