Efficiency of the crystallizing waterproofing admixture in lower-quality concrete

Abstract The article deals with the topic of a crystallizing waterproof admixture using in concrete. This type of admixture is designated for making a hardened concrete more durable by minimizing its permeability. Considering that concretes of higher strength classes meet the requirements for durability parameters in most cases, in this experiment 3 low-durability (in terms of high w/c ratio) concrete (Dmax8) batches were mixed. From each of mixture, 2 sets of samples (with and without the admixture) were prepared for depth of penetration of water under pressure test, strength test and water absorption test after 28 days of curing. Likewise, samples for microscopic visual assessment of crack-filling process were produced. Cracks onto these samples were intentionally introduced after their curing in time of 7 days and subsequently were further cured under water and regularly observed. According to the results, tested admixture acted more counter-productive than helpfully.