Durability of Structural Lightweight Concrete Containing Different Types of Natural or Artificial Lightweight Aggregates

Abstract

Different structural lightweight concrete mixtures of specific density and strength classes were produced by using various lightweight aggregates (LWAs) such as pumice, perlite, and rice husk ash. Their properties were evaluated in fresh and hardened states with regards to compressive strength and durability parameters such as water absorption (open porosity and capillary absorption), chloride’s penetration resistance, and carbonation depth. According to the results, most LWA concrete mixtures performed satisfactorily in terms of the designed strength and density and they could be used as structural LWA concrete mixtures. As far as the durability of LWA concrete was concerned, open porosity and resistance to the carbonation of LWA concrete were burdened with the porous nature of LWAs, while sorptivity in some mixtures and especially chlorides’ penetration resistance in all mixtures were reported to be significantly improved. The overall strength and durability performance of the designed LWA concrete mixtures could mitigate the concerns stemming from its vulnerability to extreme exposure conditions.

Perlite and Rice Husk Ash Re-Use As Fine Aggregates in Lightweight Aggregate Structural Concrete—Durability Assessment

“…The values obtained for the open porosity coefficient, after the 28th day, range from 20% to 34%, significantly higher compared to REF (13%). These results are in agreement with findings in the literature [20,29,50], indicating that the replacement of natural aggregates by LWA increases the water absorption of the LWC.…”

“…It should be mentioned that there are differences in the crushing indices of the produced LWC mixtures. Similar mixtures were produced in a preliminary study [20], albeit under different mixing conditions, and developed similar compressive strengths and highly comparable results, indicating that the effect of the different crushing indices is negligible.…”

“…Particularly, the compressive strength of PuCa and PePu increased by 20% and 28%, respectively; and by increasing the volume of Pu and Pe in the aggregate blend, the strength increased further after curing. It is known from the literature that pumice significantly improves the compressive strength in the long term, due to its pozzolanic reactivity [20,43]. Moreover, the reactive silica content of pumice provides better Si-O-Si bonding between the paste and the aggregates, as fresh cement paste penetrates into the open large pores of the LWA [44].…”

“…It can, therefore, provide supplementary CSH and other pozzolanic products for the concrete matrix [17,18]; together with the massive quantities of R found globally, this makes it a promising and highly environmentally friendly material to be used as an aggregate in the production of concrete. However, there is a limited number of studies in the literature [19,20] that explore the potential use of coarser R as a fine aggregate in LWC and so additional research is required.…”

“…Additionally, waste-expanded perlite has been studied as a replacement for quartz sand in the production of autoclaved aerated concrete [24] and as a partial or complete substitution for feldspar in the production of ceramic tiles [25]. Preliminary studies on using finer-than-4 mm perlite as a fine aggregate in LWC have shown positive results in terms of durability and strength [20]; however, further research is necessary.…”