D-optimal design of experiments applied to 3D high-performance concrete printing mix design

Automating mix design for 3D concrete printing using optimization methods

“…These parameters are the water-to-binder ratio, the sand-to-binder ratio, the dosage of the superplasticizer, the dosage of the biopolymer polysaccharide viscosity modifying agent, and the dosage of crystalline calcium silicate hydrate. The ranges of the values for those quantitative factors are close to the boundaries of the values set in the D-optimal design 51 . Specifically, the water-to-binder ratio can take values between 0.25-0.4%w, the sand-to-binder ratio between 1.7-2.4%w, a superplasticizer dosage of 0.13-0.28%w, the biopolymer polysaccharide viscosity modifying agent dosage range is 0-0.018%w and the crystalline calcium silicate hydrate dosage is between 0-0.4%w.…”

“…Each sand has different characteristics: the first sand is finer, the second is coarser and the third sand is recycled sand that was collected from the residues of the sedimentation basin of truck concrete mixer washing facilities. More details about the selected materials are available in 51 .…”

“…The designer can choose the number of mixes that he or she wishes to form. Eighteen mixes were selected with a D-efficiency equal to 100% 51 . The mixes are presented in Table 2.…”

“…The proposed testing methods are the ASTM C1437 flow test, the ASTM D3080 direct shear test and the ASTM C109 compressive strength. Starting from the mix design, a D-optimal design was used to generate the initial set of 18 mixes 51 . This is a nontraditional experimental design that can significantly minimize the number of experiments while producing statistically grounded designs with high-quality results.…”

“…To identify which admixtures would be included in the D-optimal mix design, a preliminary study was performed using probability plots 52 . Three types of cement, three types of sand, and five admixtures, including superplasticizers, are chosen in total 51 . Among the eight investigated factors, the qualitative factors are the cement types, the types of sand with different particle size distributions, and the types of superplasticizers.…”