Key Engineering Materials Vol. 599

Abstract: In this paper, a novel composite cementitious material was prepared by using steel slag and rice husk ash. The appreciate treatment processes of composite cementitious material prepared were investigated. At same time its basic performance of cement mortar, such as water demand ratio, setting time, soundness and strength were also investigated and discussed. Experimental results show that the cementitious materials prepared has good basic properties with appreciate treatment processes. It concluded that the properly treated steel slag and rice husk ash can be used to prepare cementitious material.

Abstract: The technological conditions for preparation of red mud-coal gangue lightweight pottery sand were studied. The formulation of the lightweight pottery sand was determined by comparing the sintering images. The results indicated that as to the mixture of red mud and coal gangue, the expansion temperature of mixture decreased with increasing the content of red mud. The composition of 30% red mud and 70% coal gangue was determined to have the best expanding performance in this study and selected. The optimal technological conditions of lightweight pottery sand was systematically studied through orthogonal experiment method and accordingly the lightweight pottery sand with bulk density of 617.89kg/m³, water absorption of 0.14%, the single particle compressive strength of 2.95MPa, the softening coefficient of 0.98 was successfully prepared with the selected composition after preheated at 550°C for 20 min and then sintered at 1300°C for 20min.

Abstract: With the global warming, phase change materials are being expected to be applied in asphalt pavement to help lower its surface temperature. In this study, a kind of composite phase change material was prepared and its technique parameters were optimized through theoretical analysis and experimental study. A solid-liquid phase change material, with melt point of 43°C and phase transition heat of 161.6J/g, was used as core. The organophilic montmorillonite (OMMT) was used as a carrier and can prevent leakage of the melted phase change materials. The results showed that the ratio of OMMT to lauric acid was 2.6:1, and the melting temperature and time were 74°Cand 1.5hours, respectively. The composite phase change material prepared in this study had the phase transition latent heat of 36.168J/g and the transition temperature of 40.094°C. And the experimental results are in good agreement with theoretical analysis.

Abstract: The central concept of semi-flexible pavement (SFP) is to combine the best qualities of concrete and asphalt pavement by means of filling the voids of the large gap asphalt mixture (LGAM) with good fluidity grout. The major purpose of this study is to determine the feasibility of utilizing waste rubber powder in the grout so as to reduce the stiffness of the semi-flexible pavement. In this paper, seven kinds of grout were prepared by adding different volume dosage of the waste rubber powder and seven kinds of SFP were also prepared. By means of rutting, dynamic elastic modulus and low-temperature cracking performance tests, the performances of SFP were compared. The experimental results illustrated that the waste rubber powder was suitable to the semi-flexible pavement material. With the dosage of rubber powder increased, the anti-rutting, dynamic modulus of SFP decreased, but the low-temperature cracking of SFP was improved. Preferably, the volume dosage of the waste rubber powder should be not more than 20%.