Durability of CFRP sheet was studied in simulative way under marine environment(such as single factor effect and multi-factor combined effects of salt solution immersion,wet and dry cycles in salt solution,freeze and thaw cycles).

An experimental study on the performance of concrete inside fly ash in sulfate environment was carried out by dry-wet cycle in water or sodium sulfate solution and measurement of dynamic lnodulus of elasticity.

They experienced dry-wet cycle in sodium sulfate solution.

The profiles of chloride ion in concrete were obtained from the results of experiments that were under typical conditions such as dry-wet cycle and immersion condition.

To improve the ability of concrete against seawater corrosion,a kind of anticorrosion admixture for the concrete is investigated by experimental method of chlorine ion permeability,sulfate corrosion,drying and wetting cycles in the corrosion envionment,and the mechanism of the admixture is analytically studied.

Unconfined compression tests are conducted on expansive soil under different drying and wetting cycles.

Numerical simulation of deformation process of expansive soil slopes due to dry-wet cycling;

Test results indicated that the dry-wet cycling was the main factor of the problem.

The long-term immersion, dry-wet cycling and alternating-current resistance are selected as the testing methods in this thesis.

Research on mechanical properties of expansive soil under wetting-drying cycle;

With the research object of expansive soil in Naming, Guangxi , combining on the observation date of expansive soil slope of field engineering ,the change law of the strength and deformation and damage to cumulative fatigue of manipulated expansive soil under wetting-drying cycle are disclosured by wetting-drying cycle test in laboratory.

Through analyzing the experimental data,the change law of expansive soil with the strength of wetting-drying cycle is found out.

A CT study on the crack evolution of expansive soil during drying and wetting cycles;

By using drying and wetting cycles in water and sulfate solution,the effects of several factors on the resistance to sulfate attack of lightweight aggregate concrete were studied,the factors include:water binder ratio,air-entrained agent,content of fly ash and lightweight aggregate.

By using drying and wetting cycles in water and sulfate salt solution, the effect of several factors on the resistance to sulfate salt crystallization of cementfly ash composite binder materials was studied, the factors include: waterbinder ratio, fineness and content of fly ash, fly ash blended with less silica fume and sulfate salt solution concentration.