Abstract Stabilized soil with cement has been a widely used solution in geotechnical projects and requires the molding of numerous specimens to investigate their properties in destructive tests, restraining the reuse for other analysis. Also, distinct sample dimension has been utilized in the research without taking this effect into account. Recognizing these needs, the height and diameter (H/D) ratio effect on cement-stabilized soil mechanical behavior was assessed in the present work. Using sandy soil, Unconfined Compression Strength (UCS), Indirect Tensile Strength (ITS) and Ultrasonic Pulse Velocity tests were performed varying the curing period (7 and 28 days), cement type (I and III) and content (6, 7, 8, 9 and 10%), based on conventional (127 x 100 mm) and reduced dimension (105 x 50 mm) specimens. All variables, individually and combined, affected the compression and tensile strengths of the mixtures, resulting in greater gains for the ones molded with type III cement in reduced dimension, at 28 days of curing. The dimension as an influential variable was statistically established using the variance analysis (ANOVA) at a significance level (α) of 0.05, in which reduced dimension showed an average superior resistance of 21.3%. Mixtures molded with H/D ≥ 2 demonstrated strong correlation (R2 = 0.93), pointing to the possibility of ITS prevision through the P-wave velocity nondestructive tests.

Abstract The presence of unsaturated flow in tropical lateritic soils of unknown hydromechanical behavior may lead to severe geotechnical problems. It is known that soil-water characteristic curves (SWCC) are a valuable tool to define this behavior and facilitate the suction estimation, acting on tests performed with no control of such parameter. This article aimed to determine and model the SWCC for 3 unprecedented tropical soils, in the undisturbed and the compacted conditions, from the Paraná state, located in the south of Brazil. The soils studied are one clay and two sands, all lateritic. The pressure plate and the filter paper methods were used to determine the SWCC. The samples were carved and submitted to the drying paths. Furthermore, Mercury Intrusion Porosimetry (MIP) tests were performed in samples of the studied soils in order to obtain the pore size distribution (PSD), contributing to the bimodal definition of curves and the prediction of SWCC main parameters. Both techniques (pressure plate and filter paper) were combined and the SWCC was adjusted by Gitirana & Fredlund model, which efficiently represents the shape of the traditional curves for tropical soils. Furthermore, the SWCCs were predicted by PSD and obtained satisfactory numerical fits. All SWCC presented air entry values in the macropores that are characteristic of soils as the lateritic, given that its structure was considered a key factor in the shape of the curves.