Study on Energy Absorption Characteristics and Frost Resistance of Foam Concrete and EPS Concrete

Author:Guo Lei

Supervisor:yang xue chun

Database:Doctor

Degree Year:2019

Download:49

Pages:128

Size:15733K

Keyword:

Foam concrete and EPS concrete have been widely used in recent years due to their thermal insulation,both have the characteristics of energy absorption buffering and large deformation.At present,foam concrete and EPS concrete are mainly used in the field of building wall insulation,and people have little research on the mechanics and energy absorption cushioning properties of the two materials.Multiple sets of foam concrete and EPS concrete specimens were prepared by adding different admixtures,different admixtures,antifreeze agents and different mixing ratios.After this,the mechanical properties under static and dynamic conditions were tested and the microstructure was microscopically analyzed,comprehensive evaluation of the energy absorption properties of two materials and the frost resistance in cold regions.Through a large number of tests,the compressive strength,energy absorption efficiency,frost resistance and microstructure of the two materials were analyzed.As the result,we propose foam concrete with excellent indicators.Applying this foam concrete to the emergency lane in traffic protection facilities.Establishment of finite element coupling model of foam concrete and motor vehicle by using finite element simulation software of adaptive method,through the vehicle at different initial speeds,under different vehicle loads,simulated the block distance of the safe-rising lanes paved by foam concrete facing the vehicle.The main research results are as follows:1.Formulated foam concrete with limestone powder,fiber,water reducing agent and waterproofing agent;formulated EPS concrete with limestone powder and waterproofing agent.According to the requirements of the specification,foam concrete and EPS concrete specimens were prepared through different mixing ratios.2.When the apparent density is the same,the study of fiber blending improves the compressive strength of foam concrete and the toughness,deformation and crack resistance of concrete and increase the mechanism of energy absorption efficiency.3.The stress-strain curves of the static test of fresh foam concrete and EPS concrete specimens were analyzed.The continuous plastic fracture of foam concrete and EPS concrete materials under stress was analyzed,and the main factors affecting energy absorption were analyzed.4.The fresh foam concrete and EPS concrete were made into cylindrical test pieces ofΦ70mm×35mm,and the Hopkinson SHPB pressure bar test was carried out to analyze the relationship between strain,stress and strain rate and energy absorption efficiency of the two materials;it is concluded that the energy absorption efficiency of foam concrete is better than EPS concrete.5.Research was conducted for the frost resistance of foam concrete.The surface of the test piece was coated with silane waterproofing agent and os type waterproofing agent,and then subjected to freeze-thaw cycle test.The incorporation of fibers has little effect on the frost resistance;after the silane-based waterproof layer is applied alone,the hydrophobic silicone is formed on the surface of the slurry to reduce the permeability of the foamed concrete;after the composite coating of the silane and os-type waterproofing agent,frost resistance is further improved;under the same mixing ratio,the surface area of the test piece coated with water repellent and non-water repellent after freeze-thaw cycle was studied,and the surface area of the uncoated waterproofing agent was increased,and the contact area with water increased,frost resistance is reduced.6.To systematically study the frost resistance of EPS concrete,replace the cement with inert mixed materials or increase the particle size of EPS particles,and analyze the intrinsic relationship between the blending amount of concrete and the compressive strength of concrete;the effect of brushing single layer and double layer waterproofing agent on the frost resistance of EPS concrete;it is concluded that with the increase of waterproof coating,the freeze resistance of EPS concrete is gradually improved.7.Establishment of finite element analysis for coupling induction between vehicle wheel and foam concrete energency lane,study vehicles at different loads,under different initial speed conditions,the blocking performance of foam concrete to vehicles.The research model proposed in this paper can also be used to predict the performance of the safe-rising lane blocking system under different initial speeds and different wheel loads,and provide relevant basis for the application of foam concrete retarding materials to other traffic protection systems.