Dataset regarding calcium bentonite and sodium bentonite as stabilizers for roads unbound

The collected dataset derives from the laboratory testing of bentonite clay investigated as a stabilization technology for the unbound layers of road pavements. The effect of two kinds of bentonite (calcium based and sodium based) are assessed on two aggregate types commonly used as road construction materials. The investigation program, performed by means of repeated load triaxial tests, encompasses the different combinations of bentonite and aggregate types; two replicate specimens are tested dried for each condition. Considering the global need for ensuring well-performing road infrastructures while employing environmentally sound construction technologies, this dataset documenting the potential of bentonite clays used as road stabilizers can be of interest for several road stakeholders.


a b s t r a c t
The collected dataset derives from the laboratory testing of bentonite clay investigated as a stabilization technology for the unbound layers of road pavements. The effect of two kinds of bentonite (calcium based and sodium based) are assessed on two aggregate types commonly used as road construction materials. The investigation program, performed by means of repeated load triaxial tests, encompasses the different combinations of bentonite and aggregate types; two replicate specimens are tested dried for each condition. Considering the global need for ensuring well-performing road infrastructures while employing environmentally sound construction technologies, this dataset documenting the potential of bentonite clays used as road stabilizers can be of interest for several road stakeholders.
© 2022 The Author(s

Value of the Data
• In light of the significant global need for efficient and sustainable construction and maintenance of road pavement infrastructures, the dataset is useful to appraise the stabilization potential of two types of bentonite clay (calcium based and sodium based). • As road pavements are an important infrastructural asset for each nation's economy, the employment of green efficient technologies for road stabilization is relevant for several stakeholders such as researchers, engineers, professionals, entrepreneurs and agencies. • The dataset can be used to quantify the stabilization potential attained by bentonite clay in roads unbound. The experimental data can be analysed according to several models to appraise resilient modulus and deformation properties. • The rock aggregates tested in the investigation campaign have been selected as they are largely used in the central part of Norway as road construction materials. The main mechanical properties that are directly relevant to road pavement engineering and can be assessed by means of RLTTs are elastic stiffness (resilient modulus, M R ) and the resistance against permanent. As an example, considering crushed rock aggregates stabilized with calcium based bentonite, Figs. 1 and 2 depict the experimental values of M R and axial plastic deformation, respectively, as a function of the number of load cycles N . Furthermore the trend of the experimental data can be determined considering the several regression models available in literature [11][12][13][14][15][16] .

Experimental Design, Materials and Methods
Both the crushed rock and natural gravel aggregates were derived from local quarries in Trøndelag region, Norway. They have been selected as they are largely used as construction materials in both unbound and bound layers of road pavements realized in the central part of the country [17] . The two types of calcium based and sodium based bentonite clays were supplied by industrial producers. The overarching goal of the research was to investigate environmentally friendly technologies that can be used for the construction or stabilization of road unbound layers [18 , 19] ; in this regard, the application of bentonite is still relatively unexplored [20][21][22] .
The research activities were accomplished performing RLTTs according to Multi-Stage Low Stress Level (MS LSL) indicated in the CEN standard "13286-7 Cyclic load triaxial test for unbound mixtures" [23] . A RLTT comprised thirty loading steps, where each of them referred to a precise combination of deviatoric stress σ d and triaxial stress σ t as illustrated in Fig. 3 : the former one was applied according to a sinusoidal pattern using a hydraulic jack, while the latter one was applied by pressurized water. Given a constant value of σ t and a dynamic deviatoric stress σ d,dyn , the resilient modulus M R is defined as with ε a,el the average axial resilient strain evaluated by the three axial LVDTs.