This study comparably assessed the pozzolanic effect of silica fume (SF) and ground rice husk ash (RHA) as supplementary cementing materials on the properties of blended cement pastes and concretes. A commonly commercial silica fume (SF) and locally-produced rice husk ash (RHA) samples with two finenesses (one with larger size than cement and the other with smaller size than cement) were used i...

A fluorinated silyl functionalized zirconia was synthesized by the sol-gel method to fabricate an extremely durable superhydrophobic coating on cotton fabrics by simple immersion technique. The fabric surfaces firmly attached with the coating material through covalent bonding, possessed superhydrophobicity with high water contact angle ≈163 ± 1°, low hysteresis ≈3.5° and superoleophilicity. The...

Sulphates usually affect calcium aluminates in cements. Sulphate ions might have negative effects on cement hydration and it would be a reason of decrease in cement strength. In this study, the effects of Na2SO4 solution on the concretes made from OPC with oil shale ash (OSA) addition (0, 15 and 30%) were investigated. Concretes with 15% OSA gave the lowest value of Length Change Factor (LCF). ...

Roads are currently essential links of communication and economic development. However, these roads progressively requiring higher quality materials, implying a greater impact on the environment, in order to withstand high levels heavy vehicle traffic. Therefore, this research proposes use industrial by-products create bituminous mixtures which more resistant durable than traditional ones. The ...

A coupled elastoplastic-damage constitutive model taking into account chemo-induced elastoplastic-damage effects for the modeling of coupled chemothermo-hygro-mechanical behavior of concretes at high temperature is proposed in this article. A three-step operator split algorithm for the integration of the rate coupled constitutive equations is developed. Consistent tangent modulus matrices for c...

as regards if curing stops for some time and then resumes again, then strength gain will also stop and reactive, in this study with choose suitable curing conditions after improper first curing (recurring) for normal and silica-fume concrete, effect of this curing conditions on strength and permeability was investigated. the results from tests such as compressive strength, capillary water absor...

Introduction: The present study aimed to evaluate the impact of PbO nano and micro-sized fillers on ordinary and heavy concretes for different photon energies. Material and Methods: The MCNPX Monte Carlo code (version 2.6.0) was used for all simulations in the present study. A model of narrow-beam geometry was validated and utilized to calcul...

In this study, 10–50% of porcelain tile polishing residue (PPR) was used as an additive or partial replacement cement in concrete. The consumption kept constant by correcting the amount sand for each mixture. Concrete workability (slump) reduced up to 88.72% when PPR replaced 30%, while it only 4.10% added concrete at same levels. Compressive strength 28 days increased 92.22% with 50% additive,...

One research field in Leipzig deals with the design of high strength lightweight-aggregate concretes (HSLWAC). Due to the huge waveband of this concretes with all possible combinations of lightweight-aggregates and mortar matrix the formulation of general rules is difficult. Therefore both components lightweight-aggregates and mortar matrix will be investigated in detail in order to achieve a d...