Different Forms Of Alkali On Concrete Alkali - Aggregate Reaction

Utilizing 80℃steam conservation, we have researched the alkali of different formation, containing extra alkali,dissolved alkali included in clinker,alkali combined by dicalcium silicate and tricalcium aluminate of clinker mineral and alkali included in mixed materials,which have influence on alkali-silicate reaction of concrete。Meanwhile, we have observed that the alkali of various different formation corrodes condition of glass aggregate。Results show:extra alkali have the greatest influence on alkali-silica reaction of concrete,dissolved alkali included in clinker seriously attends alkali-silica reaction of concrete; Second is the alkali contained by dicalcium silicate and dicalcium aluminate of clinker mineral。In the clinker mineral, alkali contained by dicalcium silicate and forming KC23S12 attend alkali-silica reaction less than contained by dicalcium aluminate and forming NC8A3,alkali included in mixed materials have least influence on alkali-silica reaction。In order to analyze the reason of producing above-mentioned phenomenon,we have used liquid state means to synthesize the most main hydrating products of cement existed in cement stone, that it is calcium silicate hydrate gel and Ettingite,have compared the ability of combining alkali of two hydrating products of cement and have tested and compared the ability of combining alkali of calcium silicate hydrate gel of different C/Si ratio,calcium silicate hydrate gel of contained sulphate root ion and calcium silicate hydrate gel of aluminum ion。Results show :the ability of combining alkali of Ettingite is lower than calcium silicate hydrate gel,Meanwhile,the ability of combining alkali of calcium silicate hydrate gel reduces,while C/Si ratio increases,but calcium silicate hydrate gel of contained sulphate root ion and aluminum ion can increase the ability of combining alkali of calcium silicate hydrate gel,nevertheless,sulphate root ion possibly dissolves from calcium silicate hydrate gel and the ability of combining alkali of calcium silicate hydrate gel also lowers with prolong of conserving time。But when calcium silicate hydrate gel combines some aluminum ion,the ability of combining alkali of calcium silicate hydrate gel enhances and keeps very steady。With long-term effect,hydrating products of cement of zeolite type can form,which has advantage of preventing alkali-silica reaction。In term of analysis of alkali equilibrium of typical pre-decomposed kiln in our country,we put forward to technological ways of preventing alkali-aggregate reaction:â'ˆChoosing and adjusting materials proportion in order to lower alkali content of clinker。â'‰In the case of permitting technology,decreasing sulphur trioxide content of clinker,properly enhance dicalcium silicate content of clinker and decreasing dicalcium acuminate content of clinker。â'ŠChoicely joining mixed materials containing some aluminum oxide,adjusting and making parameter excellent,in order to realize that cement includes but alkali in cement does not attend alkali-silica reaction。...