Experimental Research On Rapid-solidification Inorganic Adhesive

At present,more and more old building structures at home and abroad have different degrees of safety hazards,and it is necessary to adopt timely and effective reinforcement measures.In recent years,with the wide application of new materials and new technologies in the field of reinforcement,the reinforcement and reconstruction in China has developed rapidly,and methods and means for reinforcement have also become increasingly diversified,and the technique of planting bar has attracted great attention due to its unique engineering superiority.Bonding anchorage materials in planting bar technology are generally divided into organic and inorganic types.But currently,the organic type of planting adhesives commonly used in engineering have been found large engineering limitations,such as long setting time,poor heat resistance,poor durability,and environmental pollution,etc.Recently,domestic scholars have begun research on inorganic adhesives.Most of the research objects are cement-based inorganic adhesives.The durability and heat resistance of such inorganic adhesives have been obviously improved,but the issues of large shrinkage and long setting time still remain.Therefore in this paper,a theoretical analysis of the anchoring mechanism of the technique of planting bar were firstly made.Combined with the experimental research results of relevant scholars at home and abroad,the failure modes of the planted bar specimen under static load and the ultimate bearing capacity of corresponding failure modes were summarized,and the main factors affecting the anchoring performance and the bond-slip constitutive model were analyzed.Then,based on the increasingly complex construction conditions in the current planting bar projects and the increasing strength requirements for the anchorage adhesive,the industrial waste silicate minerals and an alkali stimulating agent are used as raw materials by proportion test to obtain a new kind of inorganic anchorage material for planting bar.Then,through several pullout tests on the concrete substrate,a set of applicable construction process for technique of planting bar was concluded according to the characteristics of this inorganic adhesive.In the test of concrete blocks,the failure mode and failure mechanism of the planted bar specimens under monotonic static loading were analyzed through its load-displacement curves,and the factors of qualitative influence of anchoring performance such as bar diameter,anchoring depth and concrete strength were discussed in detail.In the test of concrete frame,the anchoring angle was considered as the influencing factor for the first time.Through statistical analysis of the test results,the quantitative effect of anchoring depth and anchoring angle on the bearing capacity of anchorage was studied.In the durability test of this inorganic adhesive,the short-term and long-term anchorage strength and stiffness of the planted bar specimens were analyzed through comparison with the organic planted bar specimens,and its good durability performance was verified.Finally,from the perspective of structural safety and engineering economy,this paper derives the approximate calculation formula of anchoring depth through theoretical derivation,and proposes a simple and practical design method of inorganic planting bar based on anchoring depth,which can be applied to various different conditions.Then,according to the statistical data of the experimental results of the concrete frame test from chapter four,the calculation formula of the bearing capacity of the inorganic planting bar was linearly fitted,and the design method of it based on the bearing capacity was proposed.Then the results of theoretical calculations and test results are compared by using an example.The results were in good agreement with each other,which proved the feasibility of the method for the design of planting bar as a reference.Finally,the inorganic adhesive was applied to an actual reinforcement project.The on-site barbed-spot sampling test results met the requirements and further its good engineering applicability was confirmed.