During the manufacturing of foam concrete, conventional chemical and physical foaming methods are still inadequate for regulating and stabilizing the bubble properties. In this work, a onepot method, denoted as in -situ mechanical frothing, was proposed preparing foam concrete by vigorously stirring the mixture of water, cement, sandy soil, and foaming agent. Sandy soil (SS) was used in the content range of 25 -75 % as cement replacement to decrease the binder consumption and reduce costs. The influence of in -situ mechanical frothing technology and SS dosage on the properties of paste rheology, pore structure, compressive strength, and thermal properties was investigated. The results showed that the average pore size of foam concrete prepared by this method is between 45.73 and 74.58 mu m. The compressive strength of the formed foam concrete at dry density of 600 -1000 kg/cm 3 was 2.78 -16.37 MPa, which was 85% -231 % higher than that the standard values. The incorporation of SS resulted in smaller and homogeneous pore structure in foam concrete. Moreover, foam concrete with 25 -75 % SS dosage showed 7 -40 % decrease in thermal conductivity. The overall analysis showed that the 25 -50 % S S - incorporated foam concrete enabled achieving higher standard properties through in -situ mechanical frothing.

The dumping of titanium slag (TS) and fly ash (FA) could lead to the occupancy of abundant land resources and the pollution of air, soil and underground water. The meso-regulatory function of the lightweight and thermally stable porous TS makes it a feasible material as the fire-resistive cementitious composites (FRCCs). This paper proposed a novel low-carbon FRCC with favorable high-temperature resistance by using TS and FA. Then, the mechanical properties and mechanism improving the heat resistance were systematically studied. The results revealed that the addition of TS with proper quantity decreases the mass loss by 19.6% and degradation degree of mechanical strength by 31.8% after 800 degrees C heating. The thermally stable perovskite and akermanite phases in TS are conducive to improving the stability of mineral phases during high-temperature heating. Meanwhile, the porous structure of TS enhances the thermal insulation of FRCC, which postponed the mineral phase decomposition. In addition, the secondary hydration effect of FA consumes a large amount of Ca(OH)2, which effectively weakens the deterioration caused by the decomposition of Ca(OH)2 after 600 degrees C heating. Based on the CT results, the variations of internal pore structure including pore distribution, porosity, and fractal dimensions, were systematically analyzed. It is found that the TS particles can effectively optimize the internal pore distribution and limit the generation and deterioration of macro-pores. Moreover, the thermal damage model of the prepared FRCC was established by combining the pore structure deterioration degree and residual mechanical strength. Finally, compared with traditional fire-resistive fillers, the low carbon emission of the prepared FRCC was verified.