Experimental Study On The Preparation Of Early Strengthened Recycled Brick With Typical Inorganic Waste Residue

Producing recycled solid brick is one of the important ways of reducing waste environmental pollution and reusing of construction waste and household waste incineration furnace slag. The production of early strong recycled brick by means of improving the early strength of recycled brick could be helpful to reach the goal of in-site waste processing. As a result, curing time and occupied area could be effectively reduced. Production efficiency could be improved and the transportation cost could be reduced. In this thesis, effects of materials characteristics of recycled aggregate, water reducing agent and early strength agent on early strength of recycled brick were studied by using XRD, SEM and material mechanical performance measuring techniques et al. With the compound addition of moderate amount of water reducing agent and early strength agent, construction waste recycled brick with 8h early compressive strength of 12.73 MPa and slag recycled brick with 8h early compressive strength of 10.82 MPa were prepared, respectively. The recycled brick prepared by us satisfied the strength demand of MU10. These results can provide experimental basis for the construction of mobile waste processing system and are of important engineering application value.Experimental results showed that high 8h early strength of recycled brick could be obtained under conditions of continuous gradation, using suitable recycled aggregate containing small size aggregate, less amount of coarse aggregate, high initial moisture content, low sediment content, proper water cement ratio and proper aggregate cement ratio. The longer the curing time and the compression time, the higher the early compressive strength of recycled brick was obtained. High 8h early strength could be obtained by optimizing the mix proportion and processing parameters as follows: the maximum size of recycled aggregate was 6mm, coarse aggregate content was 50%, initial water content was 11.9%, water cement ratios was 0.6, cement aggregate ratio was 1:9, pressure holding time was 8s.When using a single additive, addition of both naphthalene water reducing agent and polymer water reducing agent could increase the early compressive strength of recycled brick made from either construction waste or slag. The optimum content of naphthalene series water reducing agent and polymer series water reducing agent were 0.75% and 0.3%, respectively. Addition of early strength agent, such as sodium chloride, sodium silicate and sodium carbonate could increase the early compressive strength of construction waste recycled brick and slag recycled brick. The optimum content of sodium chloride, sodium silicate and sodium carbonate were 2%~3%, 1%~2% and 3%, respectively. The addition of triethanolamine reduced the early strength of recycled brick.When using complex additive, effects of naphthalene water reducing agent, sodium chloride, sodium silicate and sodium carbonate on early strength of construction waste recycled brick were decreasing in the following order: Sodium carbonate > Na Cl > water glass > naphthalene series water reducing agent. Construction waste recycled brick could obtain the highest 8h early strength by complex addition of 0.75% Naphthalene series water reducing agent, 1% sodium chloride, 3% sodium silicate and 3% sodium carbonate, respectively. In the case of slag recycled brick, effects of naphthalene water reducing agent, sodium chloride, sodium silicate and sodium carbonate on early strength were decreasing in the following order: sodium carbonate > sodium chloride > naphthalene series water reducing agent > sodium silicate. Slag recycled brick could obtain the highest 8h early strength by complex adding 0.75% of Naphthalene series water reducing agent, 1.5% of sodium chloride, 5% of sodium silicate and 4% of sodium carbonate, respectively.