This paper presents the development of a portable vane rheometer to estimate concrete plastic viscosity and yield stress. The apparatus can be used not only in laboratory but also on construction site. In this study, new blade geometry was proposed to minimize the effect of segregation of concrete during testing, and also to expand the wide range of concrete work­ability with a slump of approximately from 7 cm to fluid concrete, and concrete with high plastic viscosity such as concrete with mineral additions. The used blade (U shaped and reversed) allows reducing the vibration of the apparatus, and ob­taining more stable measurements. The obtained results permit validating the rheometer test procedure and confirmed that the results are reliable, with a low coefficient of variation of 9% for repetitive test and of 5.8% for reproductive tests.

The objective of this paper is to investigate the influence of type and dosage of recycled sand (RS) and gravel on the fresh and mechanical properties of concrete. Experimental program was conducted on concretes made with different ratio of substitutions (15, 30, 70, and 100%) of natural sand and gravel with RS and gravel. At the fresh state, slump, air content, and density were measured at the exit of the mixer, and then at 30, 60, and 90 min after mixing. Tests were also performed for compressive strength at the age of 1, 7, and 28 days, whereas elastic modulus measurements were done at 28 days. The results indicated that maintaining the workability of recycled aggregate concrete depends on sand or gravel substitution and their rates. Up to 30 min, slump values were decreased, but after that, no substantial change in slump values was observed. Air content increased and density decreased, with increasing recycled aggregate content (sand or gravel). Mechanical properties, such as compressive strength and modulus of elasticity, were lower than those of reference concrete.

This paper investigates the properties and durability of cementitious composites incorporating solid-solid phase change materials (SS-PCM), an innovative heat storage material. Mortars with varying SS-PCM contents (0%, 5%, 10%, 15%) were formulated and characterized for rheological, structural, mechanical, and thermal properties. Durability assessment focused on volume stability (shrinkage), chemical stability (carbonation), and mechanical stability (over thermal cycles). Mortars with SS-PCM exhibited significant porosity and decreased mechanical strength with higher SS-PCM content. However, thermal insulation capacity increased proportionally. Notably, the material’s shrinkage resistance rose with SS-PCM content, mitigating cracking issues. Despite faster carbonation kinetics in SS-PCM mortars, attributed to high porosity, carbonation appeared to enhance long-term mechanical performance by increasing compressive strength. Additionally, SS-PCM composites demonstrated superior stability over thermal cycles compared to reference mortars.