# Evaluation of Early-Age Compressive Strength in Winter Prefabrication: A Comparative Study
## 1 Introduction  
The continual evolution of the construction industry has been significantly characterized by the introduction of novel methodologies that prioritize efficiency, sustainability, and the reduction of construction timelines [1; 2; 3]. The precast concrete technique has established itself as an innovative approach, revolutionizing the traditional paradigms of structural development and execution. Based on the off-site manufacture of structural elements, this method represents an innovative alternative to conventional methods of pouring concrete on-site, underlining a shift in building methodologies [4]. At the heart of concrete prefabrication lies an innovative engineering process that facilitates the production of architectural and structural components within a controlled factory environment substantially distant from the actual site of construction. This prefabricated methodology has several advantages, ranging from unparalleled dimensional accuracy to the substantial acceleration of construction schedules. Concrete, known for its durability, is pivotal in this methodology, serving as the backbone that supports structural integrity and facilitates a wide range of architectural expressions [5; 6; 7]. The underlying efficiency of the prefabrication process is further enhanced by the standardization of components, which not only enables mass production but also makes construction requirements more cost-effective. Such a methodological transformation has not only changed the construction landscape but has also become a cornerstone in meeting the growing demand for sustainable and resilient construction practices [8]. This exposition lays the groundwork for an in-depth examination of the complexities inherent in concrete prefabrication, defining its qualities, the challenges it faces, and its transformative influence on contemporary construction methodologies [9]. Concrete prefabrication signifies a fundamental shift, redefining the traditional methodologies of constructing edifices. It encompasses the off-site manufacture of building components, marking a new era in construction characterized by superior precision, efficiency, and economic viability. Within this innovative framework, concrete is of essential importance, subjected to complex processes to ensure not just optimal strength but also lasting durability [10]. A critical aspect of prefabrication is the early demolding of concrete elements, a procedure that demands acute attention to the factors that influence compressive strength [11; 12]. The industry norm suggests casting concrete on day 'd' and proceeding with demolding on day 'd + 1', or in some instances, as soon as 20 h after casting. However, this expedited process encounters notable challenges, especially under wintry conditions, where the concrete's hydration process, crucial for strength development, is impeded by low temperatures. This poses a significant risk to attaining the minimum compressive strength of 10 MPa required for the safe handling of prefabricated panels [13; 14; 15; 16; 17]. In addressing these challenges, a diverse array of strategies is employed, from the use of warm mixing water to the application of heating hoods, highlighting the dynamic approaches to optimizing prefabrication processes against winter-related challenges. This research focuses on the detailed examination of early-age compressive strength across concrete compositions, each designed to mirror the distinctive conditions prevalent in prefabrication factories. This study looks at the complexities of winter-induced challenges with the aim of elucidating strategies to improve the prefabrication process. It provides new perspectives by systematically examining two industrial systems for mitigating winter-induced challenges, advancing current understanding, and offering practical solutions for improving the structural integrity of precast concrete elements. The ultimate aim is to preserve the structural integrity of precast concrete elements in adverse weather conditions.