It has been reported that owing to a densification of the internal structure of concrete, adding mineral admixtures leads to a more brittle behaviour. Therefore, with the intention of modifying (increasing the strength of) foamed concrete to make it suitable for structural purposes by means of admixtures and lightweight aggregate addition, the effect of these additions on the failure mechanism under compressive and tensile loading using different techniques is evaluated and discussed in this paper. Eight different mixes, made using a pre-formed foam, were investigated with varying density (different foam volumes), nominally 1300, 1600 and 1900 kg/m3, without/with admixtures (silica fume, fly ash and superplasticizer) and lightweight aggregate. The Digital Image Correlation (DIC) technique was adopted to measure the deformations and strains on the surface of a specimen under uniaxial compressive load. Meanwhile, a Video Gauge technique was used to measure the horizontal deformation of discs during a splitting tensile test. From elasticity, fracture and fractal points of view, it was found that, for the same density, brittleness increases with many of the additives while it reduces with inclusion of lightweight aggregate. However, for all mixes, the lower the density (higher added foam volume), the higher the ductility.
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机译:据报道,由于混凝土内部结构的致密化,添加矿物掺合料会导致较脆的性能。因此,为了通过掺合料和轻质骨料添加来改性(提高)泡沫混凝土使其适合于结构目的,评估了这些添加对使用不同技术的压缩和拉伸载荷下破坏机理的影响。并在本文中进行了讨论。研究了使用预制泡沫制成的八种不同混合物,其密度(不同的泡沫体积)不同,标称重量分别为1300、1600和1900 kg / m3,无/有掺合料(硅粉,粉煤灰和高效减水剂)和轻质骨料。采用数字图像相关技术(DIC)测量单轴压缩载荷下试样表面的形变和应变。同时,在断裂拉伸试验期间,使用视频量表技术来测量光盘的水平变形。从弹性,断裂和分形的观点来看,发现对于相同的密度,许多添加剂使脆性增加,而包含轻质骨料则降低了脆性。但是,对于所有混合物,密度越低(泡沫添加量越高),延展性越高。
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