Deep-Learning-Based Segmentation of Fresh or Young Concrete Sections from Images of Construction Sites

The objective of this study is to evaluate the feasibility of deep-learning-based segmentation of the area covered by fresh and young concrete in the images of construction sites. The RGB images of construction sites under various actual situations were used as an input into several types of convolutional neural network (CNN)–based segmentation models, which were trained using training image sets. Various ranges of threshold values were applied for the classification, and their accuracy and recall capacity were quantified. The trained models could segment the concrete area overall although they were not able to judge the difference between concrete of different ages as professionals can. By increasing the threshold values for the softmax classifier, the cases of incorrect prediction as concrete became almost zero, while some areas of concrete became segmented as not concrete.

Curing Assessment of Concrete with Hyperspectral Imaging

The curing of concrete significantly influences the hydration process and its strength development. Inadequate curing leads to a loss of quality and has a negative effect on the durability of the concrete. Usually, the effects are not noticed until years later, when the first damage to the structure occurs because of the poor concrete quality. This paper presents a non-destructive measurement method for the determination of the curing quality of young concrete. Hyperspectral imaging in the near infrared is a contactless method that provides information about material properties in an electromagnetic wavelength range that cannot be seen with the human eye. Laboratory tests were carried out with samples with three different curing types at the age of 1, 7, and 27 days. The results showed that differences in the near infrared spectral signatures can be determined depending on the age of the concrete and the type of curing. The data was classified and analyzed by evaluating the results using k-means clustering. This method showed a high level of reliability for the differentiation between the different curing types and concrete ages. A recommendation for hyperspectral measurement and the evaluation of the curing quality of concrete could be made.

Dynamic Measurements for Determining Poisson’s Ratio of Young Concrete

Knowledge of the elastic properties of concrete at early age is often a pre-requisite for numerical calculations. This paper discusses the use of a laboratory technique for determining Poisson’s ratio at early concrete age. A non-destructive test set-up using the impact resonance method has been tested and evaluated. With the method, it has been possible to obtain results already at 7 hours of concrete age. Poisson’s ratio is found to decrease sharply during the first 24 hours to reach a value of 0.08 and then increase to approximately 0.15 after seven days.

Flexible procedure for concreting in hot and dry climate based on Phase Change Material

The article presents the possibilities of using a flexible approach in designing production processes in construction on an example of concreting in a hot and dry climate. The basic drawback of typical quality management system procedures is their rigidity. It is based on the assumption that building processes are carried out in favorable conditions. Meanwhile, these conditions often change to a large extent during the process, and the accuracy of weather forecasts is limited. The aim of the article is to demonstrate the advantages of flexibility procedures for concreting on the example of concrete modification with phase-change materials. The conducted research has shown a reduction in the risk of structure damage during maturing of young concrete due to the use of hybrid phase-change materials in the conditions of central Syria climate. Phase-change materials provide lowering of the thermal peak in the initial maturation period and unification of the temperature in the cross-section of the element (limitation of the thermal gradient). At the same time, PCM’s slightly reduce the compressive / tensile strength of the concrete. As a result, this reduces the risk of cracking of the concrete element, which is the basis for ensuring greater durability of the element and a longer life cycle of the building.

Prototypowy manipulator ja-wa do automatycznego betonowania ścian

In the context of automatic construction of buildings analyzed prototype, ja-wa system, which integrates aspects of computer controlling the manipulator of the testing of allowable construction progress (according to the results of the analysis rise the endurance of the young concrete, laid in layers made earlier). Imposing of concrete mix (controlled intervals) with finish a surface septum is performed by a computer-controlled manipulator-machine, which moves the track system ferry. Indicated rationality and low capital intensity of solutions.

Methods Considering the Concrete Creep due to Shrinkage

Creep of concrete is a phenomenon that is not only significant in the long term, but also at young concrete. The paper deals with methods considering the tensile creep of concrete due to shrinkage. It was proved, that the tensile creep can be taken into account by simplified methods called Age-adjusted Effective Modulus Method with the ageing coefficient χvalue falling between 0.4 and 0.45. Calculated values were experimentally verified by means of Ring-test.