Roghani Hossein, Nanni Antonio, Bolander John E
Department of Civil and Architectural Engineering, University of Miami, Coral Gables, FL 33146, USA.
Department of Civil and Environmental Engineering, University of California, Davis, CA 95616, USA.
Materials (Basel). 2023 Aug 6;16(15):5489. doi: 10.3390/ma16155489.
This paper reports on a combined experimental and numerical modeling investigation of cracking of concrete slabs with GFRP reinforcement. At this stage of the project, attention is given to early-age cracking driven by plastic shrinkage, preceding longer term considerations of cracking resistance over the service life of field applications. Of interest is the effectiveness of GFRP reinforcement in restricting plastic shrinkage cracking. Nine small-scale slab specimens were subjected to controlled evaporation rates. Images of crack development were acquired periodically, from which crack width estimations were made. Comparisons were made between slabs reinforced with conventional steel and those reinforced with GFRP, along with control specimens lacking reinforcement. During the period of plastic shrinkage, the time of crack initiation and subsequent crack openings do not appear to be influenced by the presence of the reinforcing bars. To understand this behavior, six early-age bond tests were conducted for both types of the bars after 1, 2, and 3 h exposure to the controlled evaporation rate. In addition, concrete strength development and time of settings were measured using penetration resistance tests on a representative mortar. The numerical modeling component of this research is based on a Voronoi cell lattice model; in this approach, the relative humidity, temperature, and displacement fields are discretized in three-dimensions, allowing for a comprehensive investigation of material behavior within the controlled environment. Based on the measured bond properties, our simulations confirm that the reinforcing bars restrict crack development, though they do not prevent it entirely.
本文报道了一项关于玻璃纤维增强塑料（GFRP）增强混凝土板开裂的实验与数值模拟相结合的研究。在项目的这个阶段，重点关注由塑性收缩驱动的早期开裂，而不是对现场应用使用寿命期间抗裂性的长期考虑。感兴趣的是GFRP增强在限制塑性收缩开裂方面的有效性。九个小型板试件经受了可控的蒸发速率。定期获取裂缝发展图像，并据此估算裂缝宽度。对用传统钢筋增强的板、用GFRP增强的板以及未增强的对照试件进行了比较。在塑性收缩期间，裂缝起始时间和随后的裂缝开口似乎不受钢筋存在的影响。为了解这种行为，在将两种类型的钢筋暴露于可控蒸发速率1、2和3小时后，进行了六个早期粘结试验。此外，使用对代表性砂浆的贯入阻力试验测量了混凝土强度发展和凝结时间。本研究的数值模拟部分基于Voronoi元胞晶格模型；在这种方法中，相对湿度、温度和位移场在三维空间中离散化，从而能够在可控环境中全面研究材料行为。基于测量的粘结性能，我们的模拟证实钢筋限制了裂缝发展，尽管它们不能完全阻止裂缝发展。
