Effects of pre-steaming treatment on high-temperature and low-humidity drying characteristics of super-heavy timber with boxed-heart of Korean red pine and Douglas-fir

• Published in: Drying technology Vol. 41; no. 5; pp. 794 - 803
• Main Authors: Lee, Nam-Ho, Lee, Changjin
• Format: Journal Article
• Language: English
• Published: Philadelphia Taylor & Francis 10-04-2023; Taylor & Francis Ltd
• Subjects: Building materials; Construction materials; Cross-sections; Drying; Final moisture content; High temperature; Humidity; internal checks; Moisture content; Moisture effects; moisture gradient; Pine; Pine trees; Prevention; Steaming; surface checks
• ISSN: 0737-3937; 1532-2300
• DOI: 10.1080/07373937.2022.2119246

This study aimed to investigate how pre-steaming affects the drying times, final moisture contents (final MCs), and prevention of checking during the high-temperature and low-humidity drying process of boxed-heartwood Korean red pine (Pinus densiflora S. et Z.) and Douglas-fir (Pseudotsuga menziesii) with 20 × 20 cm and with 30 × 30 cm cross sections. Although average final MCs of the larger cross sections were slightly higher than those of smaller cross sections, all were over-dried between 3.3% and 8.1% MC, compared to the in-use moisture content for outdoor building materials. All the pre-steamed samples were only slightly defected by surface checks of 5 mm or less in width. The sample timbers with the 20 × 20 cm cross-sectional size were slightly defected by internal checking, whereas those with the 30 × 30 cm cross-sectional size were severely defected. However, there was no clear impact of pre-steaming time on the prevention of internal checking.