Experimental Study On The Construction Waste Clay Brick Powder As Active Admixture

At present,China's annual production of construction waste about 1 billion tons,and its utilization rate is less than 5%?Without disposal,a large number of construction waste are simple landfilling,occupying cultivated land,destructing soil and polluting the atmosphere and water,bringing serious environmental load.At the same time,the construction waste has the resource utilization attribution,and the landfill submerged the potential value of the material.Therefore,the recycling of waste clay brick(WCB),which accounts for about 50% of the proportion of construction waste,can not only effectively support the construction waste disposal,but also has very importantly environmental significance and sustainable development significance.This article is based on the WCB of physical activation,slag powder,lime,gypsum and alcoholamine to activate,then confirm the preparation of the active admixture of concrete,testing the concrete working performance and mechanical performance changing,and by the means XRD,TGA and MIP explore microscopic mechanism of enhanced highly active admixture.The results show that with the increase of the replacement rate of waste brick powder(CBP),the strength of mortar decreases.And the substitution rate is more than30%,the strength decreases significantly.With the increase of the proportion of slag in the composite powder,When the composite ratio is 4 to 6,the excitation effect is the best.The substitution rate of the lime is increased,the strength of the mortar reduced,when the dosage is 1.5%,the excitation effect is the best.The gypsum excitation effect is not obvious;The strength of the mortar is higher than that of the cement powder of 4to 6,the strength of the mortar with 1.5% lime is obviously improved and the strength of 28 days is not changed.The strength of the cement powder is increased and the coagulation time is prolonged,The ratio of 4: 6,the ratio of 4: 6 compound with alcoholamine,CBP mixed with 1.5% lime,CBP mixed with 1.5% lime with the content of 0.15 ‰ CA1 excitation for the better excitation program,can be more significant to improve the activity of brick,made of high activity admixture.The change of the substitution ratio of the active admixture has little effect on the working performance of the concrete.With the increase of the CBP replacement rate,the concrete strength is reduced,30% cement can be replaced in C30 concrete,15%cement can be replaced in C40 concrete;4 to 6 increase in admixture ratio,concrete strength increased firstly and then decreased,C30 concrete can replace 30% cement,C40 concrete can replace 25% cement;composite ratio 4 to 6 with alcoholamine admixture The replacement rate increases,the concrete strength increases first and then decreases,30% cement can be replaced in C30 concrete,30% cement can be replaced in C40 concrete;with the CBP mixed with 1.5% lime admixture increase in the ratio of concrete strength increased firstly and then decreased,in C30 can replace 25% of the cement,in C40 can replace 20% cement;with the CBP mixed with 1.5% lime with alcoholamine admixture increase in the rate of concrete increased increased firstly and then decreased,In C30 can replace 25% of the cement,in C40 can replace 20% cement.After the incorporation of CBP,the AFt peak was observed,the CH peak decreased after compound excitation,the peak of CH peak and SiO2 decreased with the composite ratio 4 to 6 and the peak of C3 S,the AFt peak was increased.The concentration of Ca(OH)2 in the DTG curve increased with the loss of water quality and the mass loss of Ca(OH)2.And the hydration products of cement clinker are promoted after the excitation.The hydration products of the cement powder are formed.The distribution of the pores is mainly concentrated in the range of 10~100nm,forming more dense and high hydration products.