Bond Properties And Flexural Behavior Of High-Strength Lightweight Aggregate Concrete Beams Reinforced With High-Strength Steel Bars

The benefits of high-strength rebar include its great strength,superior seismic performance,significant safety reserves,and material savings,among others.High-Strength Lightweight Aggregate Concrete(HSLWAC)has various benefits,including low weight and high strength,exceptional durability,strong seismic performance,and thermal insulation.It is a building material that supports sustainable development,and it is frequently utilized in construction projects with favorable effects on the economy,society,and the environment.On this basis,the mechanical properties of HSLWAC,the bonding and anchoring characteristics of high-strength reinforcement to HSLWAC,and the flexural characteristics of beams are studied experimentally and theoretically in this article.The principal areas are:(1)The mechanical property tests of HSLWAC with nine groups were completed,and it was determined what effects the volumetric sand rate,aggregate particle size,and volume fraction of steel fibers had on the material’s working properties,fundamental mechanical properties,and key characteristic points on its full stress-strain curve.A database was created,information on steel fiber lightweight aggregate concrete from both domestic and foreign sources was gathered,and a stress-strain principal structural model that could be used for each type of steel fiber HSLWAC was proposed.The findings demonstrate that the volumetric sand rate and aggregate particle size have a minimal overall impact on the basic mechanical properties of HSLWAC,and that as these parameters increase,the effect on the material’s splitting tensile and flexural strengths is within 11%;The incorporation of steel fibers with different volume rates significantly changed the damage morphology and the mechanical properties of HSLWAC.At last,the proposed model’s predicted results are also in good agreement with the test curves.(2)In order to investigate the effects of concrete strength,volume fraction of steel fibers,and other variables on the damage form and bond performance,four groups of full-beam bonded anchorage experiments with high-strength rebar and HSLWAC were conducted.The formulations for the ultimate bond strength and bond-slip primary structural model between high-strength rebar and HSLWAC was proposed.The test findings demonstrate that the damage types of the specimens are splitting damage and splitting pull-out damage.High-strength rebar and HSLWAC have good bonding performance,and the ultimate bond strength rises as concrete strength and steel fiber admixture levels are increased.(3)The effects of variables like reinforcement rate and concrete strength grade on the damage form,moment-span deflection curve,deformation capacity,characteristic load,concrete strain,and steel strain of the specimens were revealed after three tests on the flexural performance of high-strength steel reinforced high-strength lightweight aggregate concrete beams were completed.The findings demonstrate that the current national and international codes are applicable in a good way to the ultimate bearing capacity of high-strength steel reinforced high-strength lightweight aggregate concrete beams as well as to the maximum crack width and deflection of the members during normal service phase.However,the assessment of the average crack spacing for the members is relatively conservative.In this paper,a stress-strain principal structure model applicable to various types of steel fiber HSLWAC is established,and the ultimate bond strength expression and bond-slip principal structure model between high-strength rebar and HSLWAC are proposed,the applicability of domestic and international codes to the flexural performance of high-strength steel reinforced high-trength lightweight aggregate concrete beams in service phase is verified and provides pertinent support and a basis for the promotion of high-strength rebars and HSLWAC in future engineering fields.