A Study on Cement Made by Partially Replacing Cement Raw Materials with Municipal Solid Waste Ash
The use of Municipal Solid Waste incinerator bottom ash (MSWI) and Calcium Carbide Waste (CCW) as a part of cement raw material was investigated. The purpose was not only to dispose of the wastes, but also to alleviate some environmental problems, by reducing resources usage, CO 2 emissions and energy consumption in cement manufacturing. The replacement of MSWI and CCW in raw meal was 5 and 10 percent. Chemical composition and general characteristics, as well as setting times and compressive strength, of the MSWI cements and CCW cements were tested and compared with conventional cement. The chemical compositions of MSWI cements and CCW cements were similar to the control cement, except that the SiO 2 component in MSWI cements was higher than that in control cement but the CaO component was lower. Setting times of cement pastes were slightly different when MSWI and CCW were used as raw materials in cement. The longer setting times of these cement pastes than those of control cement is due to lower C 3 S and higher C 2 S levels than in CC. Compressive strength of CCW cement mortars was closed to that of the CC cement, whereas compressive strength of mortar produced from MSWI cements was rather smaller than the control cement mortar, especially at higher MSWI percentags.
Soil Modification and Stabilization Potential of Calcium Carbide Waste
Laterite was treated with calcium carbide waste and lime as the control, to ascertain its modification and stabilization potential, in incremental order of 2% up to 10 %. Atterbergs limits test, compaction test, California bearing ratio (CBR) and unconfined compressive strength (UCS) test was performed on laterite treated with both additives. The use of χ2 test to compare results of tests, showed that there is no significant difference between the modification potential of both additive as reflected in χ2 values of 1.293, 0.995 and 0.650 obtained from the comparison of liquid limit, plastic limit and plasticity index test results. However difference was observed with CBR and 7 day UCS test results as χ2 values of 13.75 and 11.64 respectively were higher than the standard value of 9.49 obtained from statistical Table at 4 degree of freedom and 5 % level of significance. Based on result of tests, calcium carbide waste is recommended for use in soil modification and stabilization, as usage will provide an effective way of disposing calcium carbide waste.
A New Vacuum Pressure Infiltration CFRP Method and Preparation Experimental Study of Composite
In order to prepare a carbon-fiber-reinforced polymer composite (CFRP) with ideal microstructure and properties, a new vacuum pressure infiltration CFRP method is proposed based on an analysis of existing CFRP preparation process methods. Research on composite material preparation systems was carried out by using this new method principle. The system mainly includes a fiber pre-forming module, a vacuum heating infiltration module, a hot-press curing molding module, and a data acquisition control module. Under the conditions of natural curing at 0 MPa + 6 h + 25 °C, vacuum heating curing at –0.05 MPa + 30 min + 80 °C, and hot-press curing at 0.7 MPa + 5 min + 50 °C, a two-dimensional (2D) CFRP with excellent microstructure and properties was successfully prepared. Observing the microstructure of the prepared composite material, it can be found that the inside of the composite material was sufficiently and uniformly infiltrated, and common preparation defects such as holes and delamination were effectively controlled. Through the performance test, the bending strength of the material reached 790 MPa.